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An exploration of the lumbar loads and affective responses to lumbar pain on lower limb amputees who use a prosthesis

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Title:
An exploration of the lumbar loads and affective responses to lumbar pain on lower limb amputees who use a prosthesis
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Book
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English
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Perrotti, Tracy Ann
Publisher:
University of South Florida
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Tampa, Fla.
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Subjects

Subjects / Keywords:
Biomechanics
Accelerometer
Spine
Survey
Back pain
Dissertations, Academic -- Biomedical Engineering -- Masters -- USF   ( lcsh )
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government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )

Notes

Summary:
ABSTRACT: 80% of the American population experiences back pain and it is the most common cause of limited activity in people of age 45 and under. Determining the reasons for back pain and developing new ways to treat it have been extensively researched over the past decade. However, very little research has been done on low back pain of amputees. There are four million existing amputees living in America and 250,000 people become new amputees each year. 70% of this group is lower limb amputees and a large number use a prosthesis of some kind to aid in the functions of daily living (Amputation and Limb Deficiency). Not all amputees use a prosthesis because of pain involved, aesthetics, and cost. In order to increase the use of prosthetics among amputees, the reasons why they do not use them must be fully understood. With this knowledge better prosthetic designs can be created.The purpose of this study is to first determine the prevalence of back pain among lower limb amputees who use a prosthesis and then to quantify the accelerations in the spine of this group and compare it to subjects who are not amputees. The findings of this study will be used to determine if back pain is a common complaint, if it interferes with daily activities, and if the use of a prosthesis causes abnormal loads in the spine of amputees. A cross-sectional descriptive survey was created and distributed to lower limb amputees who use a prosthesis and to a control group. In addition to the survey, several subjects were recruited to wear an accelerometer located over the L5-S1 vertebrae and walk at several speeds down a pathway. A maximum acceleration was determined for each step as well as the difference in acceleration between opposing legs. Also measured was the effect of a leg length discrepancy (LLD) on accelerations and back pain.As a result of this research it was found that a high percentage of amputees experience back pain and the prevalence is higher than that of controls. It has shown that there is a difference between the acceleration patterns of amputees and non-amputees, but further research is needed to show that this difference is what causes the higher prevalence of back pain. The trend of side dominance and its increase with increased walking speed for amputees has been shown as well as a general population trend of increased acceleration of the spine with increased speed. In relation to walking speed, the study has also shown that the perception of speed among amputees is slower than that of controls. This study has also supported the notion that a difference in leg length could cause low back pain.
Thesis:
Thesis (M.S.B.E.)--University of South Florida, 2005.
Bibliography:
Includes bibliographical references.
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Mode of access: World Wide Web.
Statement of Responsibility:
by Tracy Ann Perrotti.
General Note:
Title from PDF of title page.
General Note:
Document formatted into pages; contains 155 pages.

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aleph - 001709548
oclc - 69121984
usfldc doi - E14-SFE0001327
usfldc handle - e14.1327
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SFS0025648:00001


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ABSTRACT: 80% of the American population experiences back pain and it is the most common cause of limited activity in people of age 45 and under. Determining the reasons for back pain and developing new ways to treat it have been extensively researched over the past decade. However, very little research has been done on low back pain of amputees. There are four million existing amputees living in America and 250,000 people become new amputees each year. 70% of this group is lower limb amputees and a large number use a prosthesis of some kind to aid in the functions of daily living (Amputation and Limb Deficiency). Not all amputees use a prosthesis because of pain involved, aesthetics, and cost. In order to increase the use of prosthetics among amputees, the reasons why they do not use them must be fully understood. With this knowledge better prosthetic designs can be created.The purpose of this study is to first determine the prevalence of back pain among lower limb amputees who use a prosthesis and then to quantify the accelerations in the spine of this group and compare it to subjects who are not amputees. The findings of this study will be used to determine if back pain is a common complaint, if it interferes with daily activities, and if the use of a prosthesis causes abnormal loads in the spine of amputees. A cross-sectional descriptive survey was created and distributed to lower limb amputees who use a prosthesis and to a control group. In addition to the survey, several subjects were recruited to wear an accelerometer located over the L5-S1 vertebrae and walk at several speeds down a pathway. A maximum acceleration was determined for each step as well as the difference in acceleration between opposing legs. Also measured was the effect of a leg length discrepancy (LLD) on accelerations and back pain.As a result of this research it was found that a high percentage of amputees experience back pain and the prevalence is higher than that of controls. It has shown that there is a difference between the acceleration patterns of amputees and non-amputees, but further research is needed to show that this difference is what causes the higher prevalence of back pain. The trend of side dominance and its increase with increased walking speed for amputees has been shown as well as a general population trend of increased acceleration of the spine with increased speed. In relation to walking speed, the study has also shown that the perception of speed among amputees is slower than that of controls. This study has also supported the notion that a difference in leg length could cause low back pain.
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An Exploration of the Lumbar Loads and A ffective Responses to Lumbar Pain on Lower Limb Amputees Who Use a Prosthesis by Tracy Ann Perrotti A thesis submitted in partial fulfillment of the requirement s for the degree of Master of Science in Biomedical Engineering Department of Chemical Engineering College of Engineering University of South Florida Major Professor: William E. Lee, Ph.D. Georgios Stylianides, Ph.D. Eric Coris, M.D. Edward Quigley, Ph.D. Date of Approval: August 31, 2005 Keywords: biomechanics, accelerometer, spine, survey, back pain Copyright 2005, Tracy Ann Perrotti

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Dedication To my family for always supporting me in whatever I chose to do. To my friends who always believed in me and were always there for me.

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Acknowledgments I would like to acknowledge and ex press my gratitude to Dr. William E. Lee whose insight and scholarly advice has helped me tremendously throughout all the ups and downs of this project. I would like to thank Dr. Georgios Stylianides who helped me get the project off the ground and was always available to offer help and advice. Thank you to Dr. Ed Quigley for his support every step of the way and also the use of his equipment. I want to acknowledge Dr. Eric Co ris for being part of my committee and offering advice and support. Thanks so much to Suzanne Al ameda for all the hard work and assistance she has given me, without which I would still be working on this project. I would also like to acknowledge the assistance of Chris Monteparo. I want to express my gratitude to Courtney Li nger for the help she has given me acquiring subjects for this project. Special thanks to Fred Rakiski, Lisa Downing, Neil Gomes, Rick Hofmann, Barry Trutor, Microstrain Inc., A ndre Cournand, Richard Troung and Jaime Fargen.

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i Table of Contents List of T ables ........................................................................................................iv List of Fi gures....................................................................................................... vi ABSTRACT ..........................................................................................................ix 1.0 Introdu ction .....................................................................................................1 1.1 Structure of the Spinal Co lumn............................................................1 1.2 Amput ees.............................................................................................5 1.3 The Gait Cycle.....................................................................................6 1.4 Low Ba ck Pain .....................................................................................8 1.5 Importance of St udy.............................................................................9 1.6 Hypot hesis ...........................................................................................9 1.7 Limita tions............................................................................................9 2.0 Literature Review..........................................................................................10 2.1 Prevalence of Back Pa in....................................................................10 2.1.1 General Po pulation.............................................................10 2.1.2 Amputee P opulation ...........................................................10 2.2 Biomechanics of Low Back Pa in........................................................11 2.3 Loads on the Spine............................................................................17 2.4 Accelerometer Use in Biomech anics.................................................19 3.0 Research Design and Experimental Methods..............................................20 3.1 Survey................................................................................................20 3.1.1 Partic ipants .........................................................................20 3.1.2 Survey In strument ..............................................................20 3.1.3 Proc edure...........................................................................21 3.1.4 Data A nalysis .....................................................................21 3.2 Accelerome ter Study .........................................................................23 3.2.1 Study Participants ..............................................................23 3.2.1.1 Power Analysis...................................................24 3.2.2 Instrum entation ...................................................................24 3.2.2.1 Calibr ations........................................................26 3.2.3 Study Pr otocol ....................................................................30 3.2.4 Data A nalysis .....................................................................34

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ii 4.0 Result s.........................................................................................................37 4.1 Survey Re sults...................................................................................37 4.1.1 Amput ees...........................................................................38 4.1.2 Cont rols..............................................................................43 4.1.3 Comparison of Am putees and Cont rols.............................46 4.2 Acceleromete r Result s......................................................................46 4.2.1 Amput ees..........................................................................47 4.2.2 Cont rols..............................................................................49 4.2.3 Accelera tions.....................................................................49 4.2.3.1 Walki ng Trials ....................................................50 4.2.3.2 Simulated Leg Length Di fference (LLD) Trials..61 5.0 Discuss ion....................................................................................................66 5.1 Survey................................................................................................66 5.2 Accelerome ter Study ........................................................................67 6.0 Conclusions and Recommendati ons...........................................................72 Referenc es.........................................................................................................74 Bibliogra phy........................................................................................................80 Appendices .........................................................................................................82 Appendix 1 Survey of Lower Limb Amputees ..........................................83 Appendix 2 Contro l Group Survey...........................................................89 Appendix 3 G-Link Accelerome ter Specificati ons ...................................92 Appendix 4 Information Cover Sheet....................................................... 93 Appendix 5 Excel Spreadsheet of Su rvey Results for Amputees.............95 Appendix 6 Excel Spreadsheet of Su rvey Results fo r Controls.............110 Appendix 7 Excel Spre adsheet of Survey Result s for Amputee S ubjects .............................................121 Appendix 8 Excel Spre adsheet of Survey Results for Control Subjects................................................123 Appendix 9 Excel Spreadsheet of Maximum Acceleration Changes.....124

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iii Appendix 10 Excel Spreadsheet of Means and Standard Deviations....129 Appendix 11 Excel Spreads heet of Delta Values ...................................138

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iv List of Tables Table 2.1 Reasons for Low Back Pain and the Structures Responsible for the Pain................................................................................... 12 Table 2.2 Degenerative Changes of the Intervertebral Disc that Occur with Age..............................................................................14 Table 3.1 Survey Questi ons and Rati onale...................................................22 Table 3.2 Calibration Readings from the Agile-Lin k Software.......................28 Table 3.3 Sample Delta Value Calcul ations..................................................36 Table 4.1 Summary of Su rvey Demogr aphics...............................................37 Table 4.2 Medical Condition fo r Back Pain (A mputees)................................39 Table 4.3 Medical Condition fo r Back Pain (C ontrols) ...................................43 Table 4.4 Comparison of Survey Results on Back Pain for Amputees versus C ontrols ............................................................................46 Table 4.5 Summary of Subject Demogr aphics..............................................47 Table 4.6 Summary of the Informati on from the Subject Information Sheet (Am putees) .........................................................................48 Table 4.7 Summary of the Informati on from the Subject Information Sheet (Con trols)............................................................................49 Table 4.8 Baseline Acceleration s..................................................................50 Table 4.9 Average Peak Acceleration for Populations as a Whole...............54 Table 4.10 Average Differences between Opposi ng Legs..............................58 Table 4.11 Differences between Average Peak Acceleration of Opposing Legs Across Many St eps for Each Subject...................59

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v Table 4.12 Delta Va lue Analysis.....................................................................60 Table 4.13 Average Peak Acceleration for Populations as a Whole (LLD Tr ials)........................................................................ 63 Table 4.14 Average Differences in Average Peak Acceleration for LLD Tr ials..................................................................................... 64 Table 4.15 Delta Value Calculat ions for the LLD Trials ...................................65 Table 5.1 Average Walking Speed per Tr ial..................................................70

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vi LIST OF FIGURES Figure 1.1 Five Regions of the Vertebral Column............................................2 Figure 1.2 Anterior and Posterior Sections of t he Verteb rae............................3 Figure 1.3 Interver tebral Disc...........................................................................4 Figure 1.4 Gait Cycle Ev ents............................................................................7 Figure 2.1 Prolapsed Nucleus Pul posus........................................................ 15 Figure 3.1 G-Link Acceleromete r...................................................................24 Figure 3.2 Example of the Raw Data from the Agile-L ink Program................25 Figure 3.3 Schematic of F oot Switch Set-Up..................................................26 Figure 3.4 Accelero meter Ax es......................................................................27 Figure 3.5 Baseline Reading of Acce lerometer after Calibrati on....................28 Figure 3.6 Pendulum Results for Accelerome ter #12.....................................29 Figure 3.7 Accelerometer Attached to L5/S1 Level of Spine..........................31 Figure 3.8 Simulated Leg Lengt h Difference Set-Up......................................32 Figure 3.9 Accelerometers y axis Aligned with the Gr avity Vector and Enclosed in a Pl astic Bag..............................................................33 Figure 3.10 Determination of Maximum Di fference from Agile-Link Output.....34 Figure 3.11 Motion Analysis and Accelerometer Results.................................37 Figure 4.1 Reasons for Non-Prosthesis Use among Amputees.....................38 Figure 4.2 Nature of Amputee Back Pain....................................................... 40

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vii Figure 4.3 Intensity of Amputee Back Pain....................................................40 Figure 4.4 Frequency of Amputee Back Pain in the Last Four Weeks...........41 Figure 4.5 Level of Phantom Pain among Amputees .....................................42 Figure 4.6 Level of Phantom Sensation among Amputees............................42 Figure 4.7 Nature of Ba ck Pain C ontrols .....................................................44 Figure 4.8 Intensity of Ba ck Pain C ontrols..................................................44 Figure 4.9 Frequency of Back Pain in the Last Four Weeks Controls.........45 Figure 4.10 Peak Acceleration for the Normal Walking Speed Trials of Amputees: Amputated vs N on-amputated. Mean and Standard Deviation Error Bars are S hown....................................51 Figure 4.11 Peak Acceleration for t he Normal Walking Speed Trials of Controls: Left vs Right. Mean and Standard Deviation Error Bars ar e Shown ....................................................................51 Figure 4.12 Peak Acceleration for the Fast Walking Speed Trials of Amputees: Amputated vs N on-amputated. Mean and Standard Deviation Error Bars are Sh own....................................52 Figure 4.13 Peak Acceleration for the Fast Walking Speed Trials of Controls: Left vs Right. Mean and Standard Deviation Error Bars ar e Shown ....................................................................52 Figure 4.14 Peak Acceleration for t he Slow Walking Speed Trials of Amputees: Amputated vs N on-amputated. Mean and Standard Deviation Error Bars are Sh own....................................53 Figure 4.15 Peak Acceleration for the Slow Walking Trials of Controls: Left vs Right. Mean and Standar d Deviation Error Bars are Shown.....................................................................................53 Figure 4.16 Average Peak Accelera tion for the Normal Walking Speed Trials: Amputees vs Controls. Mean and Standard Deviation Error Bars are Show n....................................................55 Figure 4.17 Average Peak Acceleration for the Fast Walking Speed Trials: Amputees vs Controls. M ean and Standard Deviation Error Bars ar e Shown ....................................................................55

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viii Figure 4.18 Average Peak Accelerati on for the Slow Walking Speed Trials: Amputees vs Controls Mean and Standard Deviation Error Bars ar e Shown ....................................................................56 Figure 4.19 Total Acceleration fo r Different Walk ing Spe eds...........................56 Figure 4.20 Differences between Opposing Legs for Different Walking Sp eeds............................................................................59 Figure 4.21 Average Peak Accelera tion for the in. Long Trials: Amputees vs Controls. Mean and Standard Deviation Error Bars ar e Shown ....................................................................61 Figure 4.22 Average Peak Accelera tion for the 1 in. Long Trials: Amputees vs Controls. M ean and Standard Deviation Error Bars ar e Shown ....................................................................62 Figure 4.23 Average Peak Accelera tion for the in. Short Trials: Amputees vs Controls. Mean and Standard Deviation Error Bars ar e Shown ....................................................................62 Figure 4.24 Average Peak Accelera tion for the 1 in. Short Trials: Amputees vs Controls. Mean and Standard Deviation Error Bars ar e Shown ....................................................................63

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ix An Exploration of the Lumbar Loa ds and Affective Responses to Lumbar Pain on Lower Limb Amputees Who Use a Prosthesis Tracy Ann Perrotti ABSTRACT 80% of the American population experiences back pain and it is the most common cause of limited activity in people of age 45 and under. Determining the reasons for back pain and developing new ways to treat it have been extensively researched over the past decade. However, very little research has been done on low back pain of amputees. There are four million existing am putees living in America and 250,000 people become new amputees each year. 70% of this group is lower limb amputees and a large number use a prost hesis of some kind to aid in the functions of daily living (Amputation and Limb Deficiency). Not all amputees use a prosthesis because of pain in volved, aesthetics, and cost. In order to increase the use of pr osthetics among amputees, the reasons why they do not use them must be fully understood. With this knowledge better prosthetic designs can be cr eated. The purpose of this st udy is to first determine the prevalence of back pain among lowe r limb amputees who use a prosthesis and then to quantify the accelerations in t he spine of this group and compare it to subjects who are not amputees. The findings of this study will be used to

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x determine if back pain is a common complaint, if it interferes with daily activities and if the use of a prosthesis causes abnormal loads in the spine of amputees. A cross-sectional de scriptive survey was created and distributed to lower limb amputees who use a prosthesis and to a cont rol group. In addition to the survey, several subjects were recruited to wear an accelerometer located over the L5-S1 vertebrae and walk at several speeds down a pathway. A maximum acceleration was determined for each step as well as the difference in acceleration between opposing legs. Also measured was the effect of a leg length discrepancy (LLD) on accelerations and back pain. As a result of this research it was found that a high percentage of amputees experience back pain and the pr evalence is higher than that of controls. It has shown that there is a difference between the acceleration patterns of amputees and non-amputees, but further research is needed to show that this difference is what causes the higher prevalence of back pain. The trend of side dominance and its increase with increased walking speed for amputees has been shown as well as a general population trend of increased acceleration of the spine with increased speed. In relation to walking speed, the study has also shown that the perception of speed among amputees is slower than that of controls. This study has also supported t he notion that a difference in leg length could cause low back pain.

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1 1.0 Introduction 1.1 Structure of the Spinal Column The spinal column combines an intr icate architectural arrangement of bone, muscle, and soft tissue to form a stru cture of mechanical and physiological significance. Not only does the spinal column serve to protect the spinal cord, but it also transmits, attenuates and distri butes the static and dynamic forces associated with daily activities. [Keller, 2000] The spinal column is a series of vertebrae connected to one another by joints and ligaments. It has a considerable degree of flexibilit y and strength that allows it to support the head and neck, tr ansmit the weight of the body to the lower limbs, aid in locomotion, protect t he spinal cord, and aid in respiration. Therefore, it is continually s ubjected to a variety of forces. There are five main regions of the spinal column based on differences in curvature and important feat ures (Figure 1.1). The cerv ical vertebrae consist of the first seven vertebrae incl uding the atlas and the axis The next region is the thoracic region, which consists of twel ve vertebrae. The lumbar region is next with five vertebrae. It is here where most pain exists. The sacral region is next. It consists of the sacrum, which are five fused vertebrae. The last region is the coccy formed by the rudimentary vertebrae.

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Figure 1.1 Five Regions of the Vertebral Column. [www.courses.vcu.edu/DANC 291-003/] Each vertebra consists of two portions: the anterior and posterior (Figure1.2). The vertebral body is the bulkier, anterior portion of the vertebra. The structure of the vertebral body is such that it can bear mostly compressive loads. It is connected to other vertebral bodies by the intervertebral disc. This part of the vertebra plays a role in weight bearing, thus this is where the loads transmitted by the body will be greatest. The disc generally undergoes compressive, bending and torsional loads throughout daily activities. When unloaded, its intrinsic pressure is 10N per square centimeter [Nordin, 2001] but under compression the pressure becomes 1.5 times the externally applied load per unit area. 2

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Anterior Posterior Figure 1.2 Anterior and Posterior Sections of the Vertebrae. [Bridwell, 2005] The posterior portion of the vertebrae, which includes the vertebral arch, is where most of the movement of the spine originates. The vertebral arch plays a role in protecting the spinal cord and consists of pedicles, laminae and the vertebral foramen. Also included in the posterior portion are the intervertebral joints, the transverse and spinous processes and various ligaments. The intervertebral joints are formed by the facets, which also act as the site of attachment for the muscles and ligaments. The orientation of the facets is what determines the motion of the spinal segment. They also play an important role in resisting shear forces. There are many ligaments and muscles that support and aid the spinal column in its functions. The ligaments play an important role in the intrinsic stability of the spine while the muscles are active in producing its motion [Nordin, 2001]. The lumbar vertebrae consist of a larger body than other vertebrae with the fifth lumbar vertebrae being the largest and heaviest. This is consistent with 3

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its role in transmitting weight to the sacrum. Shearing stress at the intervertebral disc at this level is at its highest and the orientation of the facets helps minimize this stress. The facets are oriented at right angles to the transverse plane and at 45 angles to the frontal plane. This also allows for flexion, extension and lateral flexion but almost no rotation. The intervertebral disc plays an important load-bearing role and degeneration of the disc is the source of many low back problems. Its structure consisting of an inner and outer portion is well suited for its role (Figure 1.3). Figure 1.3 Intervertebral Disc. [Richeimer, 2005] The nucleus pulposus is the gel-like inner portion of the disc. It consists of 70-90% water and acts to dissipate and transfer loads between vertebrae. The tougher outer covering is the annulus fibrosus. It consists of fibrocartilage in a 4

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5 criss-cross arrangement that helps wit hstand high bending and torsional loads. Degenerative changes, excessive loadi ng and cyclic loading can cause weakening of the fibers and ex trusion of the inner nucleus. The extrusion of the nucleus impinges on surrounding nerves and can cause pain. 1.2 Amputees There are four million existing am putees living in America and 250,000 people become new amputees each year. Sev enty percent of this group is lower limb amputees and a large number use a prosthesis of some kind to aid in the functions of daily living [Amputation and Limb Defici ency, 2003]. Factors such as pain, aesthetics and cost limit the number of amputees who use a prosthesis. Much research has been done to improve the aesthetics of prostheses and funding is available to help offset t he cost. The pain aspect has been looked at from several angles includi ng phantom pain, phantom s ensation, residual limb pain and physical pain from the prosthes is itself. The prevalence of back pain and its effect on prosthesis use is not well understood. It is estimated that by the year 2020 there will be a 47% increase in the number of peopl e with amputations and using a prosthesis [Prosthetics-Orthot ics.net, 2004]. With this increased use, understanding pain associated with a prosthesis is of great importance. People become amputees for many reas ons including congenital defects, trauma, cancer, diabetes and vascular diseas e. In the United St ates, the majority (70%) of lower limb amputees are a result of disease followed by trauma (22%), congenital defects (4%) and tumors (4%) [Albert Einstein Healthcare Network]. The cause of the amputation and the level of amputation have an important effect

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6 on the use of a prosthesis. If the re maining limb is long and the joints are preserved it is easier to fit and use a pros thesis. The energy required to walk also decreases with longer residual limbs [Al bert Einstein Health care Network]. Lower limb amputees can be classified into five categories: foot, transtibial (below the knee), knee disarticulation (knee joint), transfemoral(above the knee) and hip disarticulation (hip joint). 1.3 The Gait Cycle The gait cycle begins when one foot touches the ground and ends when that same foot touches the ground again. It is divided into two phases: stance and swing. During stance phase the foot is in contact with ground. This occupies 60% of the gait cycle. During swing phase t he foot is not in contact with ground and this occupies the other 40% of the cycle. Stance phase can be further divided into double limb and single limb support. During double limb support both feet are in contact with the ground whereas during single limb support only one foot is in contact with the ground. One complete gait cycle consists of three periods of double support and two periods of single limb support. The gait cycle begins when either the left or right heel contacts the ground. For this discussion, the cycle will begin with right heel contact comprising the first phase of double limb support and the initiation of right stance phase. This is followed by left toe off wh ich begins the first peri od of single limb support particularly right single support. Next the left heel will contact the ground beginning the second phase of double limb support. Left single limb support is

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initiated when the right toe leaves the ground. This also begins right swing phase that lasts until right heel contact when right stance phase begins again. This is where the cycle ends. Figure 1.4 is a representation of the gait cycle. Figure 1.4 Gait Cycle Events. [www.me.dal.ca/~dp_03_8/rev2.html] There is an identifiable pattern that can be classified as normal gait which includes the actions above. In order to walk a person must be able to accomplish four things as outlined by Michael Whittle : 1. Each leg in turn must be able to support the body weight without collapsing. 2. Balance must be maintained, either statically or dynamically, during single leg stance. 7

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8 3. The swinging leg must be able to advance to a position where it can take over the supporting role. 4. Sufficient power must be provided to make the necessary limb movements and to advance the trunk. In normal gait there is no apparent difficult y in accomplishing this. There is also minimal energy consumption. When any one of these things cannot be accomplished then locomotion is impossible. In pathological gait, an abnormal patte rn is created so as to accomplish the four requirements above. This abnormal gait can be a result of a disorder in the brain, spinal cord, nerves, muscles, joints, or skeleton or as a result of pain. Any deviation from normal gait increases energy expenditure as well as the changes the loading on muscles, ligaments and joints. 1.4 Low Back Pain Low back pain is defined as sudden, sharp, persistent or dull pain felt below the waist [Fessler, 2002]. Over half of the American population suffers from either chronic or acute back pai n and reasons for the pain can include muscle strain, spinal stenosis, arthritis, spinal tumors, spinal infection, spondylolisthesis, and vertebral fracture s. More often than not the pain is classified as non-specific meaning the exact reasons for it are unknown. It is important to understand why back pain occurs in order to help treat people who suffer from it. Presently, treatment opt ions include rest, medication, physical therapy, and surgery.

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9 1.5 Importance of Study With the increase in sophistication and design of lower limb prosthetics more amputees are able to lead an active lifestyle. With the increase in activity, the prevalence of back pain could also in crease. It will be important to determine if back pain is a significant complaint am ong prosthesis users and to determine the reasons for the pain. Information about loading of the spine and abnormalities in gait with relation to back pain will ai d in designing a better prosthesis. 1.6 Hypothesis Based on previous research and underst anding, it is hypothesized that back pain will exist among amput ees and that it will be a si gnificant limiting factor in using a prosthesis. It is hypothesized t hat the prevalence of back pain will be higher among amputees than among the gener al population and that it will be more severe in intensity and occur more often. It is also hypothesized that the acce lerations in the lumbar spine of amputees who use a prosthesis will differ from that of able-bodied subjects. The amputees will have a higher average acce leration and will exhibit a larger difference between opposing legs. 1.7 Limitations This study was limited in that an insufficient number of subjects volunteered for human trials. Also t he accelerometer could not be attached directly to the spine but had to be taped to the subjects skin.

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10 2.0 Literature Review 2.1 Prevalence of Back Pain 2.1.1 General Population Eighty-eight percent of the Amer ican population experiences back pain and it is the most common cause of lim ited activity in people age 45 and under [Nachemson, 1971]. The majority of peopl e affected are between the ages of 20 to 55 with incidences starting in the 20s and reaching a maximum by age 40. Ninety percent of people report that the pai n subsides within two months but the other 10% deals with the pain longer. Due to back pain 10 million people take off work daily and an estimated $20-$50 mill ion is spent annually on back pain. Determining the reasons for back pain and developing new ways to treat it have been extensively researched over the past decade. However, very little research has been done on low back pain of amputees. 2.1.2 Amputee Population The prevalence of back pain among am putees has not been researched extensively. Several groups have reported that 50% of lower limb amputees experience persistent and bothersome back pain [Ehde, Lee, Smith]. A University of Sterling study from t he United Kingdom reported t hat 75% of the sample surveyed attributed prosthesis use to back or hip pain. Smith et al. reported back pain as more bothersome than phantom limb pain but less bothersome than

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11 residual limb pain. They reported that 71% of those surveyed experienced back pain and that persons with abov e the knee amputations we re significantly more likely to experience back pain and with greater intensity than below the knee amputees. Ehde et al. found that only 52% of those sampled experienced back pain. 43% of which rated the back pain intensity in the mild range and one quarter of the group said that the pain severely interfered with daily activities. In contrast to Smiths study, Ehde found no significant differences between above the knee and below the knee amputees. 2.2 Biomechanics of Low Back Pain Eighty percent of individuals with low back pain are said to suffer from non-specific low back pain [Nachemson, 1971]. This is due to the fact that the exact reasons for the pain are unknown. Some common causes of low back pain are muscle strain, injury to the back, over use, muscle disorders, pressure on the nerve root and poor posture. Some typica l events that occur relating to these causes are presence of lumbar sublux ations, improper lifting techniques, auto accidents, prolonged sitting, prolonged use of non-ergonomically designed equipment, excessive repetitive torsal moti ons, fallen foot arches and other foot abnormalities, and physical inactivity [Causes of Low Back Pain]. It has been repeatedly demonstrated that more than 50% of patients say that their pain originated in connection with a mechanical task and the pain is often attributed to lumbar disc herniation or a dysfunctional intervertebr al disc [Nachemson, 1971]. Other structures also identified as po ssible sources of lumbar pain include

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12 lumbar facet joints and joint capsules, lumbar and pelvic muscles and ligaments, lumbar and sacral nerves and sacroilia c joints. Instability of the spine and pathological features can produce abnorma l motion patterns and forces that can play a major role in low back pain. T able 2.1 summarizes the reasons for low back pain and structures that can be responsible for the pain. Table 2.1 Reasons for Low Back Pain and the Structures Responsible for the Pain. Reasons for Low Back Pain Muscle Strain Injury to the Back Overuse Muscle Disorders Pressure on the Nerve Root Poor Posture Structures Responsible for the Pain Intervertebral Disc Lumbar Facet Joints and Joint Capsules Lumbar and Pelvic Muscles and Ligaments Lumbar and Sacral Nerves Sacroiliac Joints In a discussion of low back pain the structures of utmost importance are the intervertebral disk, surrounding ligaments and apophyseal joints. These are considered the load bearing st ructures of the spine and the intervertebral disc is said to resist most of the compressive force. The intervertebral disc carries approximately 80% of the load across two lumbar vertebrae. The apophyseal joints and laminae carry the other 20%. The discs low capacity for remodeling and repair leave it vulnerable to the fati gue failure that has been associated with

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13 mechanical failure of the spine. As a re sult of mechanical failures, degenerative changes take place resulting in pain [Dolan]. The intervertebral discs of the lumbar spine are the largest and thickest of all the discs in the spinal column. Gilad and Nissan[1986] observed lumbar disc heights of 10.6mm +/1.4 mm anterior and 7.0 +/1.1mm posterior while Lin et. Al observed an average range of disc thickness between 7.1 mm and 12.5 mm. This is compared to the average cervical disc height of 5. 2 mm +/0.6 mm anterior and 3.2 mm +/0.7 mm posterior observed by Gilad and Nissan. The area of the discs also varies greatly. Yamada found the average cross sectional area of cervical discs to be 305 mm 2 compared to 1055 mm 2 for lumbar discs. This increased size allows the lumbar di sc to resist higher compressional loads. The intervertebral disc undergoes the most dramatic age-related changes in comparison to other musculoskeletal tissues [Buckwalter et al., 1993]. The degenerative changes that occur can lead to less mobility, reduced biomechanical properties and spinal st enosis. For example, a newborns disc contains 88% water while a 70 year olds disc contains only 64%water. This reduction in water causes the disc to harde n. It loses its ability to absorb loads and redistribute pressure. Table 2.2 includes some of the degenerative changes that occur during adulthood and in the elderly [Farfan, 1973; Burkart and Beresford, 1979; Koeller et al., 1986; Buckwalter, 1995]. As a result of these degenerative changes the disc loses its ability to keep vertebrae positioned correctly as well as maintain spacing and attachment. The

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14 degenerative and aged disc bulges more and thus increases the probability of disc herniation [Lin et al., 1978]. Table 2.2 Degenerative C hanges of the Intervertebr al Disc that Occur with Age. Age Degenerative Changes Adulthood Peripheral blood vessels disappear leading to less nutrition. Fissures and cracks appear in the disc. Nucleus becomes firmer. Water concentration decreases, decreasing disc height. Cartilage and end plates become thinner. Elderly Water content continues to decrease. Prominent fissures and clefts appear in the central region of the disc. Collagen fibers in the nucleus become less organized. General tissue degeneration, including increased collagen cross-linking. Disc herniation is 15 times more likely to occur in the lumbar spine than in the cervical spine and thus is one of the most common causes of low back pain [Freedman, 2002]. There are typically two mechanisms by which it can occur. When a very large, sudden compressive force is delivered over the lumbar spine like that which would occur during a fall or lifting a large load, injury can occur.

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This is most likely to happen when the spine is flexed and/or rotated. The second mechanism is a combination of repeated low compressive forces and flexed posture. Mechanical factors and repetitive lifting especially on a flexed or twisted spine can often disrupt the structure of the annulus fibrosus of the intervertebral disc. When the spine is flexed the annulus is stretched and thus thinner on the posterior side. Once the annulus is structurally compromised the risk of disc herniation increases as the nucleus pulposus is forced posterior. Under compression the disc acts like a hydrostatic cushion and can evenly distribute the pressure and loads. But the nucleus pulposus is only slightly compressible and bulges laterally under compression [Nordin, 2001]. The annular fibers withstand a tensile stress that has been estimated as four to five times the applied load. If the fibers have been compromised, the inner nucleus pulposus eventually begins to protrude through the weakest part of the outer ring. The prolapsed nucleus pulposus irritates surrounding nerve roots and causes pain (Figure 2.1). Figure 2.1 Prolapsed Nucleus Pulposus. [Regan, 2005] 15

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16 The apophysial joints are formed by the articulation between opposing facet surfaces. They are often referred to as facet joints. There are 24 of these synovial joints in the vertebral column and they play a role in limiting rotation about the intervertebral disc. It has been well documented that these joints cause pain and although the exact mechanism is unknown one of the best guesses is hyperextension of the joint [Thomas 2002 ]. This causes the capsule surrounding the joint to stretch. Extensive twisting or rotating of the spine can also injure these joints. If injuries are left undiagnos ed they can later lead to degenerative arthritis, which will impinge upon the nerve root and cause pain. One possible factor that researchers have looked into and that may be the cause of amputee back pain is a leg length discrepancy (LLD). A leg length discrepancy is any difference in the length of a persons legs. Several authors have implicated LLD as a possible source of back pain among the general population [White, 2004; Lee, 2003; Giles, 1981; Gofton, 1985]. They showed that back symptoms correlated signific antly with lateral trunk asymmetry and altered kinematics of the spine caused by LLD. The degree of LLD that causes back pain symptoms is still under debate. S oukka et al [1991] found that a LLD of 10 to 20 mm did not increase the inci dence of low back pain. Gross [1978] believes that a LLD of 30 mm or more w ould be necessary to produce clinically important effects. Fisk and Naigent on the other hand found a 6% incidence of patients with low back pain and a LLD of only 12.5 mm. The effect of LLD on amputees has not been studied extensively. Frieberg found that 34% of lower limb amputees had a LLD of greater than 20 mm and

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17 that in 79% of these case s the prosthesis was shorter than the sound limb. Both he and Burke were able to significantly correlate back symptoms in these individuals with lateral trunk asymmetry caused by the LLD. 2.3 Loads on the Spine Spinal loads are produced by body weight, muscle activity; pre-stress exerted by the ligaments and externally applied loads [Nordin, 2001]. There have been studies conducted on the loads of the lu mbar spine in an attempt to relate them to low back pain and there is evi dence that the severity and frequency of low back pain can be related to heavy loading of the spine [Cromwell, 1989]. Mechanical stress factors have also been re lated to the occurrence of low back syndromes [Anderson, 1977]. A majority of st udies related to loading of the spine have focused on loads while performing mechanical tasks especially lifting. Few studies have focused on loading just dur ing walking and even fewer have studied the loads for amputees during walking. The purpose of this study will be to quantify the loads for amputees and rela te it to the normal population. One of the main functions of the muscles of the trunk during walking is to stabilize the torso over the pelvis and lower extremities. This muscle activity is minimized when the segments of the spine are well aligned [Nordin, 2001]. The activation of muscles and thus subsequent a ccelerations in the spine, result in cyclic spinal loads [Callaghan, 1999]. This fluctuation in loading is a result of shifts in body weight with the greatest moment occurring about the pelvis laterolateral axis [Goh, 1998].

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18 Several methods have been used to det ermine the loads in the spine. Since the activation of the trunk muscles has been seen as the main source of the compressive force, measurements of the myoelectric activity of these muscles is one of the more popular te chniques used. Cromwell [1989] used myoelectric signals and biomechanical models to show that the peak muscle activity occurred in the erector spinae muscles just after left heel strike. The largest forces measured in these muscl es ranged from 45-65 N. These muscles are used to resist the forward motion of the body during walki ng and thus result in a spinal compression force of 1.2 times the body weight. Other groups have found similar results using other methods. Cappozzo[1984] used a mechanical model based on 3-D kinematic information from the upper torso and al so found that the trunk ex tensor muscles produced the largest moment and that it was about the latero-lateral axis. He found that the compression load was between 1.0 and 2.5 ti mes the body weight at the L3/L4 level. Khoo [1995] used a biomechanical model developed using body segment parameters from Vicon and intra abdominal pressures. He found that the peak loads occurred during heel strike and t oe-off and were measured as 1.45 and 2.07 times body weight at the L5/S1 leve l. Goh [1998] used a method similar to Khoo. Although looking at t he effects of backpack loads on the forces in the spine his control group was that of walki ng with no load. He found that the mean force also occurring at the L5/S1 level was 1.50 times body weight.

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19 2.4 Accelerometer Use in Biomechanics Accelerometers have been used ext ensively in biomechanics. The majority of applications include vibrat ion analysis. Accelerometers have been used to asses whole body vibrations while in cars, wheelchairs, sports activities and in work related situations. They are also used as measures of trunk accelerations, physical strain, activity levels and muscle power. Accelerometers have been proven reliabl e in gait analysis [Auvinet, 2001; Yack, 1993; Bouten; 1994; Moe-Nilssen, 1998]. Henriksen et al. [2003] used a triaxial accelerometer mounted on the lumbar spine to determine such gait events as mean acceleration, step length, stride length and cadence. The results were that all measurements showed high intraclass correlation coefficients. Smidt et al. [1971] used accelerometers to analyze several types of walking and concluded that a harmonic ratio could be used to determine the smoothness of gait. Robinson et al. conducted a simila r study on below the knee amputees. Mansfield and Lyons [2003] found that acce lerometers were valid sensors for the detection of heel contact ev ents during functional electrical stimulation assisted walking. They used a dual axis accelero meter placed over the lumbar spine to find a 150 ms delay between heel c ontact and negative-positive change in acceleration.

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20 3.0 Research Design and Experimental Methods 3.1 Survey 3.1.1 Participants Participants for the amputee survey were recruited from West Coast Brace and Limb (local prosthesis distributo r), John Knox Village (a retirement community), and Shands Rehabilitation Hosp ital in Gainesville, Florida. The survey was also available online at several amputee related websites. The inclusion criteria for the survey were t hat the participant be a lower limb amputee, at least 18 years of age, and able to read and write English. Participants for the control survey (non-amputees) were re cruited from the Tampa Bay area. Inclusion criteria included: at least 18 years of age and able to read and write English. The University of South Flor idas Division of Research Compliance approved the study. 3.1.2 Survey Instrument A cross-sectional descriptive survey [Appendix 1] was created to evaluate the prevalence of back pain among lowe r limb prosthesis users. The survey consisted of 40 open and close-ended questi ons that evaluated the subjects physical health, history and satisfacti on with their condition. Questions are grouped into three main categories: demographic and amputation history, prosthesis use and satisfaction, and frequency and intensity of pain. A table of the questions and rationale for why they were asked are included in Table 3.1.

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21 The control group survey (Appendix 2) consisted of 19 open and closed ended questions. This survey was a m odification of the cross-sectional descriptive survey used for the amputees. Differences included the omission of questions regarding the amputation, pr osthesis and amputee related pain. Several questions were modified to rema in relevant to non-amputee subjects. 3.1.3 Procedure Surveys were distributed via contacts at the various locations mentioned above to maintain anonymity. Each interested participant was given an information cover sheet [Appendix 3] to ex plain what the survey was for and who was conducting it. The amputee survey was also made available online at several amputee related websites. A link was posted on those websites and interested participants could complete and submit the survey online. 3.1.4 Data Analysis Data was collected and an Excel sp readsheet was created for both surveys. The data was imported into SAS and several procedures were run. From these procedures the frequency of each variable was determined as well as if there was a correlation with back pain and age, BMI, time since amputation, satisfaction with prosthesis, hip pain, gender and medications.

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22 Table 3.1 Survey Questions and Rationale. Survey Question Rationale Demographic and Amputation History Age, weight, height, gender Correlation to pain, grouping Present Occupation Pain effects work status, job is risk factor Taking medication Medication related to pain Type of prosthesis Effects on pain Side of the body prosthesis is located Effects on pain Use any other prosthesis Effects on pain Manufacturer of prosthesis Differences among types of prosthesis Weight of prosthesis Effects on pain Date of amputation Pain affected by time since amputation Date of fitting Pain affected by time using a prosthesis Prosthesis Use and Satisfaction % of time using prosthesis Effects on pain, does pain effect this time Longest time able to stand Effects from pain Reason for amputation Effect on pain Activity level before prosthesis Change due to pain Change in activity level Activity level now Effect on pain Participation in activities(# days a week) Effect on pain Satisfaction with prosthesis Effect use of prosthesis Satisfaction with life before prosthesis Different since becoming an amputee Satisfaction with life after prosthesis General Main reason for disuse of prosthesis Want to know if pain is a factor Any other assist device Effect pain Frequency and Intensity of Pain Experience back pain What survey is for Medical condition other than amputation that could cause pain May have pain but not due to prosthesis Level of back pain Similarities/differences among group Location of back pain Similarities/differences among group Nature of back pain Similarities/differences among group Frequency of pain in last 4 weeks Is pain recent Pain interfere with certain activities How bothersome the pain is Seeing a specialist Doing anything about pain and is it helpful

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23 Table 3.1 (continued) Experience hip pain Evaluate other types of pain experienced by amputees, any correlation between pains Level of hip pain Comparison to back pain Experience phantom pain Evaluate other types of pain experienced by amputees, any correlation between pains Level of phantom pain Comparison to back pain Experience phantom sensation Evaluate other types of pain experienced by amputees, any correlation between pains Level of phantom sensation Comparison to back pain Pain in non-amputated leg Evaluate other types of pain experienced by amputees, any correlation between pains 3.2 Accelerometer Study 3.2.1 Study Participants Participants for the accelerometer study were recruited from West Coast Brace and Limb and the University of S outh Florida. Inclusion criteria for amputees included lower limb amputee, no prior history of back problems, able to walk unassisted, fluent in English and at l east 18 years of age. Inclusion criteria for the control group included no prior hist ory of back problems, able to walk unassisted, fluent in English and at least 18 years of age. The University of South Floridas Division of Research Co mpliance approved the study and all participants gave written informed consent.

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3.2.1.1 Power Analysis A power analysis was performed to determine the appropriate number of subjects needed for this study. The following equation and inputs were used: n 228020%25%2(). Based on the above equation the sample size needed for the accelerometer study is 10. 3.2.2 Instrumentation The acceleration of the lumbar spine of participants in the accelerometer study was determined from the direct acceleration measurements using a 3-D accelerometer (Figure 3.1). Figure 3.1 G-Link Accelerometer [www.microstrain.com, 2005]. The G-Link Wireless Accelerometer System from MicroStrain was used. It consisted of a high speed, triaxial accelerometer with a +/10 G acceleration range and a base station transceiver that can trigger data collection from 30 meters away and transmit data continuously. The accelerometer weighs 24

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9.8715 grams. Appendix 4 contains the specifications for the G-Link wireless accelerometer system. Anti-aliasing filters are deployed by the manufacturer and consist of a two pole active filter with a -3 db frequency of 500 Hz and -40 db decade roll off. The Agile-Link program was used to record the output given by the accelerometers; graph acceleration versus sweeps and created an Excel spreadsheet file containing the raw data for a specified channel. A graph of acceleration versus time was then created. The x-axis time scale (sec) was determined by dividing the sweep value by the sweep rate (829 sweeps/sec). Figure 3.2 is an example of the raw data obtained from the Agile-Link software. -2.5-2-1.5-1-0.500.000.380.761.131.511.892.272.643.023.403.784.154.534.915.295.666.046.426.807.17Time (Sec)acceleration (g's) y axis Figure 3.2 Example of the Raw Data from the Agile-Link Program. 25

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In addition to acceleration data, heel strike data was also collected using National Instruments A/D converter (DAQCard-6062E), breakout box(SCB-68), a voltage divider, comparator circuit and force sensing resistors(FSR). The comparator circuit was built to read an input voltage from one FSR and trigger the LabVIEW program, created to record the voltage from the FSRs used as footswitches. A schematic of the set-up can be seen in Figure 3.3. Figure 3.3 Schematic of Foot Switch Set-Up. 3.2.2.1 Calibrations Two calibrations were performed. The first, as recommended by the manufacturer, calibrated the accelerometers in earths gravity field. The Agile-Link software is equipped with a plug-in that calibrates the three channels of the accelerometer. The procedure involved rotating the accelerometer about a 26

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sensitive axis and looking at the high and low values. From there a gain and offset were automatically calculated by the G-Link calibration plug-in. This plug-in allowed the output of the accelerometer to be given in units of gravitational acceleration (g). This procedure was conducted for each of the three axes shown in Figure 3.4. The results of the calibration are shown in Table 3.2. Figure 3.5 shows a baseline reading of the accelerometer after calibration and aligned so that the y-axis was parallel with the gravity vector. Figure 3.4 Accelerometer Axes. [www.microstrain.com, 2005] 27

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Table 3.2 Calibration Readings from the Agile-Link Software. Accelerometer Channel Gain Offset #12 1 208 1956 2 205 1993 3 208 1881 #15 1 196 2035 2 202 1909 3 203 2098 -0.200.20.40.60.8100.681.362.042.723.44.084.765.446.126.87.488.178.859.5310.210.911.6Time (sec)Acceleration (G's) Ch. 1 (X axis) Ch. 2 (Y Axis) Ch 3. (Z Axis) Figure 3.5 Baseline Reading of Accelerometer After Calibration. 28

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The second calibration procedure was done to prove consistency in the accelerometer readings. A simple pendulum system was designed in which the accelerometer was attached an arm. The arm was raised to an 80 angle and released. This was performed three times and the data from accelerometer was recorded by the Agile-Link software, graphed and compared. The results are included in Figures 3.6. 3.23.700.831.662.53.334.164.995.826.667.498.329.159.9810.811.612.513.3Time (sec)Acceleration (g's) Test 1 #12 Test 2 #12 Test 3 #12 Figure 3.6 Pendulum Results for Accelerometer #12. 29

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30 3.2.3 Study Protocol The study was conducted in the K opp Engineering Building at the University of South Florida. Participant s were asked to fill out the appropriate survey depending on if they were an amputee or a control subject. The investigating staff recorded height, wei ght and leg lengths. After palpating the anterior superior iliac spine (ASIS), a tape measure was used to measure the distance from the ASIS to the medial ma lleolus to determine leg length (Keeling 2004). The footswitches were then attac hed using Johnson & Johnson First Aid Waterproof tape to the heel of the shoes that the participants were wearing and the wires were secured to the leg. An accelerometer enclosed in a plastic bag was then taped with the same tape as above to the back of the subjects at the L5-S1 level of the spine (F igure 3.7). This level was determined by locating the midpoint of a horizontal lin e that connected the right and left iliac crests [Van Herp, 2000]. Subjects were then asked to walk at three different speeds down the straight, hallway for 24 feet while t he accelerometer was triggered to record the acceleration data and the footswitches recorded heel strikes. Also recorded were accelerations while the subject stood still for one minute. This allowed a baseline graph to be created which woul d show any abnormalities due to breathing and heart rate and to account for any deviations from the accelerometer not being aligned exactly wi th the axes of the room. The average of the baseline reading was used as the zero point fo r determining the maximum difference for all trials.

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Figure 3.7 Accelerometer Attached to L5/S1 Level of Spine. Eleven trials were conducted in all. Each of the selected paces for the walking trials was performed three times. For the first walking trial subjects walked at their own normal pace. For the second trial, subjects were informed to walk as fast as they could without running. This was considered the fast trial. The slow trial consisted of subjects walking as if they were browsing at a mall or window-shopping. After the three walking trials, subjects also walked with a simulated leg length difference. This was created by having the subject walk along a 16-foot by 1 foot piece of plywood with only one foot on the board (Figure 3.8). Using one or two inch plywood created simulated leg length differences of inch and 1 inch. For the amputee subjects, they performed four trials. Two consisted of simulating a prosthesis that was too short (prosthesis not on wood) and the other two a prosthesis that was too long (prosthesis on wood). Controls completed only two trials for this portion of the study, one inch trial and one 1-inch trial. All control trials were performed with the right foot on the board. 31

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Figure 3.8 Simulated Leg Length Difference Set-up. All subjects wore their usual walking shoes and were advised not to wear high heels or hard-soled shoes but tennis shoes before coming to the study. Subjects were asked not to talk and to swing their arms freely as they walked. Tape was used to mark the location of the beginning and ending point of the 24 foot distance. Also marked were a starting and ending point 2 feet before and after the 24 foot difference. Data was recorded only from the 24 foot length to exclude any beginning or ending differences in gait. Subjects were allowed several practice runs to get accustomed to wearing the accelerometer and footswitches and to walking at the indicated slow and fast paces. Accelerometer #12 was used throughout the study. The accelerometer was placed inside the plastic bag with the y-axis aligned with the gravity vector (Figure 3.9). The subject was asked to begin walking and when he crossed the 32

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beginning of the 24-foot distance the accelerometer was triggered to collect data. The triggering of the accelerometer software also triggered the LabVIEW program to begin recording data from the footswitches. Also recorded was the starting foot for each subject and the time it took to walk the 24 feet or the 16 feet for the simulated leg length difference trials. From the walking time a speed was calculated for each trial by dividing the distance by the time. The Agile Link software automatically created an Excel spreadsheet file that consisted of the recorded accelerations from each axis and the sweep number. The accelerometers were configured so as to perform 10000 sweeps at a sweep rate of 829 sweeps/sec. The minimum acceleration value for each step was obtained from the graph of acceleration versus time. It was then subtracted from the average baseline reading to determine the maximum change (Figure 3.10). The values were tabulated according to trial type (normal, fast or slow) and trial number (1, 2, or 3) and separated into amputated versus non-amputated for amputees and left versus right for controls. Figure 3.9 Accelerometers y axis Aligned with the Gravity Vector and Enclosed in a Plastic Bag. 33

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34 -2-1.8-1.6-1.4-1.2-1-0.8-0.6-0.4-0.20 0 0.250.510.761.011.261.511.772.022.272.522.773.033.283.533.784.034.294.544.795.045.35.555.86.056.36.566.817.067.317.56Time (Sec)acceleration (g's) y axis Baseline Minimum Value for each step minus the Baseline Value Figure 3.10 Determination of Maximum Difference from Agile-Link Output. 3.2.4 Data Analysis Using the raw data obtained from the Agile-Link software, the minimum value for each step (as determined by the foot switches) was labeled and subtracted from the baseline reading to determine the maximum change in acceleration. A spreadsheet of all the maximum changes was created for each subject and trial. The mean and standard deviation of the maximum changes in acceleration for each subject and trial were also calculated. Several other calculations were then made with these values. First, a delta value was created by subtracting the non-amputated value from the amputated value or the left from the right for the controls. The mean and standard deviations of the delta values were then calculated for each subject. The mean value

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35 should be zero, which shows a balanc e between both sides. The number of positive and negative values was then c ounted and a percent of negative values was calculated. The goal would be to hav e a percentage of 50% to show balance between the two sides. A percentage high er than 50% would show that when heel strike occurs for the amputated leg (o r the right leg for controls) there is higher acceleration involved and the oppos ite for a percentage lower than 50%. Two proportion difference testing was us ed to determine if the percent negative values were significantly different fr om 50%. Table 3.3 shows a sample Excel Spreadsheet column for the delta values. Secondly, a table of all the maximum changes was created and separated into non-amputated and amputated or left a nd right. For each trial type, the mean and standard deviation was calculated for each subject. After which the mean and standard deviation was calculated for amputees as a whole and controls as a whole. These averages were then plotte d in a bar graph in Excel. A t-test and two proportion difference test was perfo rmed to determine if a significant difference was present between amputees and controls. In addition to acceleration data obtai ned from the accelerometer itself, several subjects underwent gait analysis to validate the use of the accelerometer. A light-reflecting marker was placed over the accelerometer and an eight camera motion analysis system was used to record accelerations of the reflector, hence the spine at that location.

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36 Table 3.3 Sample Delta Value Calculations. 1A N 0.5951 -0.2195 -0.2049 -0.4342 -0.5707 -0.3561 -0.7024 -0.6537 -0.6 -0.5122 -0.3854 -0.6 -0.2927 -0.6292 -0.2682 -0.2927 -0.7122 Mean -0.40229 Std Dev 0.309437 Neg 16 Pos 1 %Neg 94.11765 The Motion Analysis system and EVART so ftware were used to produce a data file containing the accelerations in the x, y, and z directions. The camera system and accelerometer were synchronized to record data at the same time. The results obtained were comparable.

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37 4.0 Results 4.1 Survey Results Appendix 5 and 6 contain the results fr om the two surveys distributed. The following table summarizes the dem ographics of the two populations. Table 4.1 Summary of Survey Demographics. Controls Amputees Is Difference Significant (p<0.05) Male 21 32 Female 23 23 Total 44 55 Age (years) Mean 35.86 50.64 Yes Standard Deviation 14.13 16.44 Weight (lbs) Mean 169.61 182.70 No Standard Deviation 41.46 56.58 Height (in) Mean 67.94 66.97 No Standard Deviation 4.08 7.28 BMI Mean 25.49 27.06 No Standard Deviation 3.92 10.03

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4.1.1 Amputees 52.73% of the sample was below the knee amputees, 41.82% were above the knee amputees, 3.64% were both and one subject was neither (this subject was excluded). There were 21 left-sided amputees, 25 right-sided amputees and 7 bilateral amputees surveyed (Two subjects did not respond to this question). The average time since amputation was 12.32 years. The majority of the amputees reported that they use their prosthesis 76-100% of the time while they are awake and the reasons for not using the prosthesis are summarized in Figure 4.1. fatigue7%wounds/sores33%bad fit19%painful30%cumbersome4%other7% Figure 4.1 Reasons for Non-prosthesis use Among Amputees. 38

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39 62.96% (n=34) of the amputees reported that th ey experience back pain. 75.93% of those with back pain reported that they do not have a medical condition that causes the pain, while t he other 24.07% attribute the back pain to a certain medical cond ition. (Table 4.2) Table 4.2 Medical Condition for Back Pain (Amputees). Medical Condition Num ber of Subjects None 41 Fracture/Dislocation/ Deformation of Hip/Leg 4 Diabetes 1 Car Accident 3 Arthritis 1 Scoliosis/Spondylosis/Lordosis 2 Other 2 78.26% of those with back pain report that the pain is in their lower back and the majority (81.82%) is not seeing a specialist to alleviate the pain. Figures 4.2 4.4 are a breakdown of the nature, intensity and frequency of the pain experienced. For most amputees the pain only affected ac tivities such as walking, sleeping, normal work, recreation, and the enjoym ent of life a little bit (Appendix 5).

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Piercing12%Aching41%Throbbing12%Stabbing4%Stiffness12%Burning4%Constant15% Figure 4.2 Nature of Amputee Back Pain. 1(Little Pain)14%231%323%427%5(Severe Pain)5% Figure 4.3 Intensity of Amputee Back Pain. 40

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1-2 Times4%Few Times22%Fairly Often35%Very Often22%Every Day17% Figure 4.4 Frequency of Amputee Back Pain in the Last Four Weeks. Just under half of the sample (48.08%) reported that they experience hip pain. This is in contrast to the 75.93% and 77.78% that experience phantom pain and phantom sensation respectively. Half of the amputees who suffer from phantom pain or phantom sensation rate it as severe (4 or 5). Figures 4.5 and 4.6 represent the number of people suffering from phantom pain or sensation and how they rate the intensity level. 41

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02468101214Level 1Level 2Level 3Level 4Level 5Pain Level# of Subjects Reporting Pain Leve Figure 4.5 Level of Phantom Pain Among Amputees. 02468101214Level 1Level 2Level 3Level 4Level 5Pain Level# of Subjects Reporting Pain Leve Figure 4.6 Level of Phantom Sensation Among Amputees. 42

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43 4.1.2 Controls The sample was evenly split with 22 reporting back pain and 22 reporting they do not experience back pain. Of the 22 that reporte d back pain, 22.73% attributed it to a medical condition (Tabl e 4.3) while 77.27% reported that there was no specific condition that caused the pain. Table 4.3 Medical Condition for Back Pain (Controls). Medical Condition Num ber of Subjects None 34 Fracture/Dislocation/ Deformation of Hip/Leg 0 Diabetes 0 Car Accident 2 Arthritis 2 Scoliosis/Spondylosis/Lordosis 4 Other 2 92.31% of those with back pain report that th e pain is located in their lower back. Nearly all of those with pain (90.48%) are not seeing a specialist for it. Figures 4.74.9 show the percentages for the nat ure, intensity and frequency of pain. A rating of 1 (not at all) was the most frequent response to the pains effect on walking, sleeping, normal work, recreati on, and enjoyment of life (Appendix 6).

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Piercing30%Aching23%Throbbing31%Spasms8%Itching8% Figure 4.7 Nature of Back Pain Controls. 1(Little Pain)38%223%323%48%5(Severe Pain)8% Figure 4.8 Intensity of Back Pain Controls. 44

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1-2 Times46%Few Times23%Fairly Often23%Very Often8% Figure 4.9 Frequency of Back Pain in the Last Four Weeks Controls. 45

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46 4.1.3 Comparison of Amputees and Controls The following table is a comparison of t he back pain results for amputees versus controls. Table 4.4 Comparison of Survey Resu lts on Back Pain for Amputees versus Controls. Amputees Controls Is Difference Significant (p<0.05) Experience Back Pain 62.96% 50.00% No Pain Located in the Low Back 78.26% 92.31% Yes Nature of the Pain Aching (41.00%) Throbbing/Piercing (30.00%) Intensity of the Pain 2 (31%) 1 (38%) Frequency of the Pain Fairly Often (35%) 1-2 Times (46%) Hip Pain 48.08% 19.05% Yes 4.2 Accelerometer Results The results of the surveys given to t he subjects of the accelerometer study can be found in Appendix 7 and 8. Tabl e 4.5 summaries the demographics of those recruited.

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47 Table 4.5 Summary of Subject Demographics. Controls Amputees Is Difference Significant (p<0.05) Male 2 2 Female 1 1 Total 3 3 Age (years) Mean 29.00 42.67 No Standard Deviation 7.94 13.61 Weight (lbs) Mean 173.83 169.33 No Standard Deviation 13.81 40.46 Height (in) Mean 67.83 67.42 No Standard Deviation 2.25 2.67 BMI Mean 26.56 25.95 No Standard Deviation 1.72 4.00 4.2.1 Amputees Four amputees, three male and one fema le, were recruited to participate in the accelerometer study. One of the males was excluded fr om the results due to the inability to complete the trials. All three subjects were below the k nee amputees with two having the right side amputated and one the left side. All th ree reported being able to stand still for 46 minutes or more and that the only reason for disuse of the prosthesis was sleeping or showering. Two out of th ree reported having back pain. The pain

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48 intensity was rated as little pain occurring in the lower back once or twice in the last four weeks. One out of three amput ees reported having hip pain. One out three reported having phantom pain. Two out of three reported having phantom sensation and one out of th ree reported pain in the l eg that was not amputated. Subject 1A has been an amputee for 20 years and subject 3A has been an amputee for 56 years. Subject 2A has had the most recent amputation occurring only 1 year ago. All three subjects were able to walk independently and complete all trials. Table 4.6 summarizes the data collect ed in the subject information sheet. Table 4.6 Summary of In formation from the Subj ect Information Sheet (Amputees). Subject # Age Height (in) Weight (lbs) BMI Average Speed(ft/sec) for Normal Trials Average Speed(ft/sec) for Fast Trials Average Speed(ft/sec) for Slow Trials LLD (in) 1 38 66.0 144 23.24 3. 35 4.11 1.88 0.0 2 32 70.5 216 30.55 4. 27 5.72 3.48 0.5 3 58 65.8 148 24.07 4. 14 5.75 3.15 0.3

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49 4.2.2 Controls One out of three subjects reporte d that they experience back pain compared to the two amputee subjects that reported pain. The pain is attributed to an injury that occurred and is located in the lower back. It was reported that the pain has not occurred in t he last four weeks but that when it does occur it is severe and can moderately to extremely a ffect the activities of daily living. Table 4.7 summarizes the data obta ined from the subject information sheet for the walking trials. All three subjects were able to complete all trials. Table 4.7 Summary of In formation from the Subj ect Information Sheet (Controls). Subject # Age Height (in) Weight (lbs) BMI Average Speed(ft/sec) for Normal Trials Average Speed(ft/sec) for Fast Trials Average Speed(ft/sec) for Slow Trials LLD (in) 1C 20 65.5 170.5 27.94 3.66 5.93 2.54 0.0 2C 32 68.0 162 24.63 4.16 6.75 4.09 0.0 3C 35 70.0 189 27.11 4.56 7.39 2.93 0.5 4.2.3 Accelerations Table 4.8 is a summary of the baseline readings from the yaxis while standing still for each subject. There is no signific ant difference between these values (p< 0.05).

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50 Table 4.8 Baseline Accelerations. Subject # Baseline Acceleration (y component only)(gs) 1A -0.89 2A -0.83 3A -0.89 1C -0.87 2C -0.88 3C -0.89 The minimum value for each step was labeled and this was the value used to determine the maximum change in accele ration (peak acceleration) along with the baseline reading. Appendix 9 contains the Excel spreadsheet of the maximum changes for all subjects and tria ls. The mean and standard deviation of the maximum changes in acceleration for each subject and trial were calculated. The results are included in Appendix 10. Also calculated was the mean and standard deviation of the two different popul ations (amputees and controls). 4.2.3.1 Walking Trials The data obtained is from a small population of subjects (n=6) but there is evidence that a difference is present between the amputee and control groups. As determined using the foot switches the maximum change in acceleration occurred just before heel strike. The average maximum change in acceleration for the amputated leg was consistently higher than values for the non-amputated leg and both the left and right leg of the control subjects throughout all trials (Figures 4.104.15)

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1 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 1 peak acceleration (g's) 1A A 1A Non A 2A A 2A N 3A A 3A NA subject Figure 4.10 Peak Acceleration for the Normal Walking Speed Trials of Amputees: Amputated vs Non-amputated. Mean and Standard Deviation Error Bars are Shown. 1 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 1 peak acceleration (g's) 1C Lf 1C Rih 2C Lf 2C Rih 3C Lf 3C Rih subject Figure 4.11 Peak Acceleration for the Normal Walking Speed Trials of Controls: Left vs Right. Means and Standard Deviation Error Bars are Shown. 51

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0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 1 average peak acceleration (g's) 1A A 1A N 2A A 2A N 3A A 3A N sub j ect Figure 4.12 Peak Acceleration for the Fast Walking Speed Trials of Amputees: Amputated vs Non-amputated. Means and Standard Deviation Error Bars are Shown. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 1 average peak acceleration (g's) 1C Lf 1C Rih 2C Lf 2C Rih 3C Lf 3C Rih subject Figure 4.13 Peak Acceleration for the Fast Walking Speed Trials of Controls: Left vs Right. Means and Standard Deviation Error Bars are Shown. 52

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0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 1 average acceleration (g's) 1A A 1A N 2A A 2A N 3A A 3A N subject Figure 4.14 Peak Acceleration for the Slow Walking Speed Trials of Amputees: Amputated vs Non-amputated. Means and Standard Deviation Error Bars are Shown. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 1 average peak acceleration (g's) 1C Left 1C Right 2C Left 2C Right 3C Left 3C Right sub j ect Figure 4.15 Peak Acceleration for the Slow Walking Speed Trials of Controls: Left vs Right. Means and Standard Deviation Error Bars are Shown. 53

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54 The highest peak acceleration occurred during the fast trial of subject 1A and was 2.32 gs. This subject recor ded the highest average peak accelerations for the fast and normal trials while subj ect 2A recorded the highest average peak acceleration for the slow trials. Table 4.9 contains the average peak acceleration values for amputees as a whole and controls as a whole for all walking trials. The average peak acceleration values for am putees are higher than the controls across all trials (Figures 4.164.18 ). Figure 4.19 compares the average peak acceleration values for amputees versus controls for different walking speeds. Only the normal walking trials show a si gnificant difference (p<0.05) between the two populations. Table 4.9 Average Peak Accelerati on for Populations as a Whole. Slow Trials Normal Trials Fast Trials Amputees Mean (gs) 0.35 0.69 0.92 Standard Deviation 0.16 0.39 0.48 Controls Mean (gs) 0.34 0.41 0.89 Standard Deviation 0.10 0.09 0.38 p value for significance 0.883 0.065 0.891

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00.20.40.60.811.21.41.61.82Subjectsaverage peak acceleration(g's) AmputatedAmputees Nonamputated -Amputees Left Controls Right Contrls Figure 4.16 Average Peak Acceleration for the Normal Walking Speed Trials: Amputees vs Controls. Means and Standard Deviation Error Bars are Shown. 00.20.40.60.811.21.41.61.82Subjectsaverage peak acceleration (g's) Amputated Amputees Nonamputated -Amputees Left Controls Right Controls Figure 4.17 Average Peak Acceleration for the Fast Walking Speed Trials: Amputees vs Controls. Means and Standard Deviation Error Bars are Shown. 55

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00.20.40.60.811.21.41.61.82Subjectsaverage peak acceleration (g's) Amputated Amputees Nonamputated -Amputees Left Controls Right Controls Figure 4.18 Average Peak Acceleration for the Slow Walking Speed Trials: Amputees vs Controls. Means and Standard Deviation Error Bars are Shown. 00.10.20.30.40.50.60.70.80.91SlowNormalFastWalking SpeedAcceleration (g's) amputees Controls Figure 4.19 Total Acceleration for Different Walking Speeds. 56

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57 Also of importance is the difference between the maximum peak acceleration values for opposing legs (T able 4.10). All of the walking trials for amputees showed a significant difference between opposing legs. For controls only the normal walking trial showed a diffe rence between the left and right side. In the amputee population the average difference between amputated and nonamputated leg is as large as 0.42 gs, wh ich occurred during the fast trials. For the control population the average difference only reached a maximum of 0.06 gs, which occurred during the normal tr ials. Table 4.11 shows the differences between opposing legs for all subjects. Subject 2A had the largest difference between opposing legs and subject 1A had the smallest difference. The largest difference (0.39 gs) between amputee and control subjects was seen in the fast trials. The slow tria ls had the smallest difference (0.12 gs). Figure 4.20 compares the average difference between opposing legs for amputees versus controls for different walking speeds. The difference between amputees and controls is significant (p<0.05) across all walking speeds.

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58 Table 4.10 Average Differences between Opposing Legs. Trial Normal Fast Slow Amputated Average Peak Acceleration (gs) and Standard Deviation 0.80 +/0.49 1.11 +/0.53 0.43 +/0.21 Non-Amputated Average Peak Acceleration (gs) and Standard Deviation 0.56 +/0.29 0.68 +/0.28 0.28 +/0.02 Difference between Amputated and Non-Amputated Values 0.24 0.42 0.15 Is difference significant Yes Yes Yes Left Average Peak Acceleration (gs) and Standard Deviation 0.44 +/0.03 0.92 +/0.36 0.37 +/0.07 Right Average Peak Acceleration (gs) and Standard Deviation 0.38 +/0.03 0.95 +/0.39 0.33 +/0.02 Difference between Left and Right Values 0.06 0.03 0.04 Is difference significant? Yes No No

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Table 4.11 Differences (gs) between Average Peak Acceleration of Opposing Legs Across Many Steps for Each Subject. Subject Normal Fast Slow 1A 0.40 0.56 0.00 2A 0.36 0.68 0.39 3A 0.06 0.00 0.06 1C 0.01 0.03 0.00 2C 0.13 0.00 0.09 3C 0.05 0.07 0.03 00.050.10.150.20.250.30.350.40.45slownormalfastWalking Speedacceleration (g's) Difference between opposinglegs amputees Difference between opposinglegs controls Figure 4.20 Differences between Opposing Legs for Different Walking Speeds. 59

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60 The delta value results obtained by subtracting the amputated from the nonamputated values for amputees or the right from the left values for controls are included in Appendix 11. T able 4.12 contains the resu lts from the delta value calculations. A single proportion statistical analysis of each subjects percent negative values showed that with 95% confidence all amputees demonstrated a side preference in all walking trials. Table 4.12 Delta Value Analysis. Trial Subject Mean Standard Deviation # of Negative Values # of Positive Values % of Negative Values Is the % value different from 50% Normal 1A -0.40 0.31 16 1 94.1 Yes 2A -0.36 0.11 15 0 100.0 Yes 3A 0.07 0.11 5 12 29.4 Yes 1C 0.01 0.14 8 11 42.1 No 2C 0.13 0.14 3 11 21.4 Yes 3C 0.01 0.14 5 9 35.7 No Fast 1A -0.56 0.50 16 1 94.1 Yes 2A -0.71 0.41 13 0 100.0 Yes 3A 0.00 0.20 8 7 53.3 No 1C 0.01 0.20 10 6 62.5 No 2C 0.09 0.29 3 8 27.3 Yes 3C -0.37 0.78 7 6 53.8 No Slow 1A -0.01 0.14 12 11 52.2 No 2A -0.37 0.28 15 2 88.2 Yes 3A -0.06 0.11 13 5 72.2 Yes 1C 0.01 0.15 12 8 60.0 No 2C 0.10 0.18 2 12 14.3 Yes 3C 0.03 0.15 7 13 35.0 No

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4.2.3.2 Simulated Leg Length Difference (LLD) Trials The average peak acceleration for the amputees was again higher than that for the controls (Figures 4.21 4.24). But the amputated leg average was only higher than the non-amputated leg average during the trials in which the prosthesis was too long (Figures 4.21 4.22). For trials that created a prosthesis that was too short, the non-amputated averages were higher (Figures 4.23 4.24). 00.20.40.60.811.21.41.61.82Subjectsaverage peak acceleration (g's) Amputated Amputees Nonamputated -Amputees Left Controls Right Controls Figure 4.21 Average Peak Acceleration for the in. Long Trials: Amputees vs Controls. Means and Standard Deviation Error Bars are Shown. 61

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00.20.40.60.811.21.41.61.82Subjectsaverage peak acceleration (g's) Amputated Amputees Nonamputated -Amputees Left Controls Right Controls Figure 4.22 Average Peak Acceleration of the 1 in. Long Trials: Amputees vs Controls. Means and Standard Deviation Error Bars are Shown. 00.20.40.60.811.21.41.61.82Subjectsaverage peak acceleration (g's) Amputated Amputees Nonamputated -Amputees Left Controls Right Controls Figure 4.23 Average Peak Acceleration of the in. Short Trials: Amputees vs Controls. Means and Standard Deviation Error Bars are Shown. 62

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00.20.40.60.811.21.41.61.82Subjectsaverage peak acceleration (g's) Amputated Amputees Nonamputated -Amputees Left Controls Right Controls Figure 4.24 Average Peak Acceleration of the 1 in. Short Trials: Amputees vs Controls. Means and Standard Deviation Error Bars are Shown. The highest peak acceleration value (1.91 gs) occurred during the 1 inch long trial of subject 2A. Table 4.13 contains the average peak acceleration of the amputees as a group and the controls as a group for the LLD trials. Table 4.13 Average Peak Acceleration for Populations as a Whole (LLD Trials). in. Long 1 in. Long in. Short 1 in. Short Amputees Mean (gs) 0.61 0.72 0.58 0.68 Standard Deviation 0.42 0.48 0.34 0.38 Controls Mean (gs) 0.38 0.36 Standard Deviation 0.15 0.14 63

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64 During the LLD trials the differences between opposing legs were not as predictable. Table 4.14 contains the av erage differences for amputees versus controls. (Note: The controls only comple ted 2 trials for this part of the study. There is no difference between the short and long trials for controls. The results for subject 2As 1 inch short trial were not available). The largest difference is seen in the 1 inch long tria ls of the amputees, 0.39 gs. The delta values for the LLD trials are included in Appendix 11. The results obtained from these values are included in Table 4.15. Table 4.14 Average Differences in Average Peak Acceleration for LLD Trials. Trial Amputated Average Peak Acceleration (gs) NonAmputated Average Peak Acceleration (gs) Difference between Peak Averages (gs) Left Average Peak Acceleration (gs) Right Average Peak Acceleration (gs) Difference between Peak Averages (gs) in Short 0.50 0.69 0.19 0.35 0.40 0.05 1 in Short 0.64 0.68 0.04 0.31 0.43 0.12 in Long 0.68 0.54 0.14 0.35 0.40 0.05 1 in Long 0.94 0.56 0.39 0.31 0.43 0.12

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65 Table 4.15 Delta Value Calculations for the LLD Trials. Trial Subject Mean Standard Deviation # of Negative Values # of Positive Values % of Negative Values in Long 1A 0.08 0.55 2 2 50.0 2A -0.60 0.22 4 0 100.0 3A 0.00 0.12 2 3 40.0 1C -0.15 0.08 4 0 100.0 2C -0.28 0.17 4 0 100.0 3C 0.18 0.10 0 5 0.0 1 in Long 1A -0.12 0.19 2 1 66.7 2A -1.15 0.35 4 0 100.0 3A -0.05 0.24 2 3 40.0 1C -0.16 0.19 4 1 80.0 2C -0.09 0.25 2 1 66.7 3C 0.04 0.24 2 4 33.3 in Short 1A -0.07 0.73 1 3 25.0 2A 0.33 0.43 1 2 33.3 3A 0.03 0.09 2 2 50.0 1 in Short 1A 0.01 0.65 2 2 50.0 3A -0.04 0.33 1 3 25.0

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66 5.0 Discussion 5.1 Survey The findings of this study are c onsistent with those who found that back pain was a significant complaint among lowe r limb amputees. The 62.96% of this studys population that co mplained of back pain is comparable to previous studies [Ehde, et. al (50%); University of Sterling (75%); Smith et. al (50%)]. However, this study found the prevalenc e of back pain among amputees to be higher than that of the general population. Nachemson [1971] found that 88% of the general population experiences back pain. This is in contrast to the 50% found in this study. Reasons for this discrepancy could be due to the unknown make-up of the population used in Nachem sons study. The control group used in this study consisted only of nonamputees and amputees may have been included in his population. Nearly half of the amputee populat ion reported that t he back pain intensity was in the mild range and that it only slightly interfered wi th daily activities. This contrasts with Ehdes study that reported the pain significantly interfered with daily activities. In agreement with Ehde, this study found no significant differences between the percentage of below the knee (64.29%) and above the knee (69.57%) amputees that experience ba ck pain. The rating of the intensity of the pain was only slight ly higher for below the knee amputees compared to

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67 above the knee amputees. This is in cont rast to Smith et al. who found that above the knee amputees reported a greater intensity of back pain. The study has shown that most people who suffer from back pain experience the pain in the lower back and that there is no specific medical reason for the pain. It occurs more often among the amputee population th an that of the controls and with greater intensity. In contrast to the amputees the controls report that the pain does not interfere at all with daily activities. Based on Pearson correlation coeffi cients, there was onl y one correlation of significance (p<0.05) for the control population. It was found that body mass index correlated negatively with gender (p=0.0002). Men, on average, had a higher BMI than women. Am ong amputees the same re sult was found although without as strong a correlation (p =0.0057). For amputees the strongest correlation was between age and if the subject takes medication (p=0.0001) which would be expected. Several variables showed trends that with a higher sample size may prove to be significant correlations. Back pain negatively correlated with gender showing a trend that more men suffer from back pain. Results show a trend that when a subject experiences back pain he or she also experiences hip pain (p =0.0732). 5.2 Accelerometer Study With only a small number of subjects a major finding of this study is that the accelerometer can be a useful tool in studying the biomechanical aspects of amputee gait and imbalances that may be present. The differences shown between the amputees and controls are significant enough to warrant further

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68 investigation. Although it is unclear from this st udy whether or not these differences are a key factor in back pai n, they may be useful in determining proper fit and therapy for amputees. The maximum acceleration values correlated with which leg was amputated. The values for the amputated si de were consistently higher than that of the non-amputated side. The increased acceleration values show that the prosthesis causes some change in muscle and ligament function. This is evident in the fact that the cont rol population does not have as significant a difference between opposing legs. The difference could be attribut ed to the fact that the muscles and ligaments need to work more to stabilize the residual limb in the prosthesis and to stabilize the body over the prosthesis. With a better fit and therapy for the residual limb these differences may disappear. Several trends have emerged from t he results of this study. A comparison of the results from the delta va lue calculations show that there is a trend that more amputees demonstrate a side preference (% negative val ues are different from 50%) when compared to controls. All am putees demonstrated a side preference in all walking trials. This is compared to only one out of three controls (Table 4.12). Two out of three amputees have greater acceleration values when the amputated leg strikes the ground (%negative values > 50%). The third amputee had a higher acceleration when the non-am putated foot struck the ground. This amputee has had the longest time since amput ation, which may play a factor in the difference. The type of prosthesis did not play a role in limiting the

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69 acceleration. Subject 2A had the most sophisticated prosthesis but his acceleration values were not the lowest. Another trend observable from this data is that speed influences the difference between opposing legs for amput ees but not so much for controls (Figure 4.19). The difference between the non-amputated and amputated leg of amputees increases as the walking speed increases. There is no correlation for the control subjects. This shows that t he differences caused by the prosthesis are amplified when the speed increases. From Figure 4.20 one can see that as speed increases acceleration of the spine also increases. The only significant difference in the magnitudes of the average peak acceleration values is seen in the normal trials. This shows that on an everyday basis amputees experience higher acceleration than do nonamputees. As you deviate from norm al walking speeds, the non-amputees experience the same magnitude of acceleration. This trend may be attributable to the accommodation of gait patterns for s peeds outside of the normal. In general the amputees walked at a lower average speed for each trial when compared to controls (Table 5.1). With the experimental set-up allowi ng subjects to walk at speeds in which they deemed appropriate the trend is that amputees perceive speeds as slower than non-amputees. T he acceleration values for amputees would actually be higher than controls walking at the same speed.

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70 Table 5.1 Average Walking Speed per Trial. Slow (ft/s) Standard Deviation included Normal (ft/s) Standard Deviation Included Fast (ft/s) Standard Deviation Included Amputees 2.84 +/0.85 3.92 +/0.49 5.20 +/0.94 Controls 3.19 +/0.80 4. 12 +/0.45 6.69 +/0.73 Is difference significant? No (p=0.409) No (p=0.408) Yes (p=0.003) There appears to be no correlation between the differences in opposing legs and back pain. The amputee (3A) with the smallest difference reported back pain while the amputee (1A) with no back pain h ad significant differences between the amputated and non-amputated leg (Figures 4. 11, 4.13, 4.15). This could be due to not having enough subjects but, on the other hand, may be due to no correlation between accelerations and back pain. Other factors such as leg length discrepancies and time since amputat ion could be the cause of the back pain. Three out of six of the subjects had a leg length difference (Tables 4.6 4.7). Of the three that had a LLD all three complained of back pain. This is in agreement with White, Lee, Giles, and Gofton who have implicated LLD as a possible source of back pain. Although a cceleration patterns did not correlate with the LLD, the results obtained from creating an artificial LLD on all subjects were significant. A greater difference between opposing legs was seen for the controls when an LLD of 1 inch was creat ed but the amputees did not show such an increase. The difference remained relative ly the same as for the walking trials

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71 but the side with the maximum peak acceleration value changed. When the prosthesis was made too short (n on-amputated leg on the board), the nonamputated leg had higher peak acceleration values than the amputated. This is in contrast to the walking trials w here the amputated value was always higher. This increased acceleration for the side on the board could be du e to the fact the leg will strike the ground earlier than expect ed leaving the subject with less time to adjust and prepare for heel strike. Even though the difference increas ed for controls and the side of maximum peak acceleration changed for controls, the magnitude of the values did not change significantly. During the trials, subj ects stated that when walking on the 1inch boards they felt a difference. The inch board did not evoke such a response, leading one to believe that a LLD of inch or less might not be detectable to the subject but a differenc e of 1 inch or greater might cause concern.

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72 6.0 Conclusions and Recommendations This study has been an effective prelim inary study that has shown that the accelerometer can be a useful tool in the analysis of amputee gait. As a result of this research it was found that a high percentage of amputees experience back pain and the pr evalence is higher than that of controls. It has shown that there is a difference between the acceleration patterns of amputees and non-amputees, but further research is needed to show that this difference is what causes the higher prevalence of back pain. The trend of side dominance and its increase with increased walking speed for amputees has been shown as well as a general population trend of increased acceleration of the spine with increased speed. In relation to walking speed, the study has also shown that the perception of speed among amputees is slower than that of controls. This study has also supported t he notion that a difference in leg length could cause low back pain. As a result of being a prelim inary study several recommendations can be made as to follow-up suggestions. Recommendations include: 1. Recruiting more subjects to in crease the value of the differences. 2. Transforming the accelerations into forces on the spine. 3. Attempt to balance out the accele ration differences seen in amputees.

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73 a. This will relate to proper fi tting of prostheses, materials for prosthesis design, and proper rehabilitation and training for beginning prosthesis users. 4. Follow subjects for several months after the accelera tion patterns are balanced. a. This will give a time history of unbalancing (if it occurs) and show the importance of proper fitting. 5. Use a motion analysis camera system to determine the precise time of highest acceleration and differences in gait 6. Several effects that can be evaluated are: a. Rehabilitation Differences b. Relationship between lateral location of pain and side of amputation c. Number of prostheses owned d. Number of times a return tr ip was made to the prosthetist e. Length of residual limb 7. Differences when performing other activities such as climbing stairs.

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74 References Author unknown. Design Revision. www.me.dal.ca/~dp_03_8/rev2.html 5/05. Author unknown. G-Link Accelerometer. 2005 www.microstrain.com 5/05. Author unknown. Company Profile. Prosthetics-Orthotics Net. January 16, 2004.www.prostheitcs-orthotics.net 11/03. Author unknown. Amputation and Limb Deficiency. August 2003. http://biomed.brown.edu/ courses/BI108.html 12/03. Anderson GBJ, Ortengren R, Nachems on A. Intradiskal pressure, intraabdominal pressure and myoelectric back muscle activity related to posture and loading. Clinical Orthopaedics and Related Research 1977; 129:156-163. Auvinet B, Berrut G, Touzard C, Moutel L, Collet N, Chaleil D, Barrey E. Reference data for normal subjects obtained with an accelerometric device. Gait and Posture 2002; 16:124-134. Bouten CV, Westertoerp KR, Verduin m, Janssen JD. Assessment of energy expenditure for physical activity using a triaxial accelerometer. Medical Science and Sports Exercise 1994; 26:1516-1523. Bridwell, K. Vert ebral Column. www.spineuniverse.com/displayart icle.php/article 1286.html 5/05. Buckwalter, JA. Soft tissue agi ng and musculoskeletal function. Journal of Bone and Joint Surgery 1993; 75A(10): 1533-1548.

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75 Buckwalter, JA. Aging and degeneration of the human intervertebral disc. Spine 1995; 20(11): 1307-1314. Burkart, AL, Beresford, WA. T he aging intervertebral disc. Physical Therapy 1979; 59(8): 969-970. Burke MJ, Roam V, Wright V. Bone and joint changes in lower limb amputees. Annals of Rheumatoid Disorders 1978; 37: 252-254. Callaghan JP, Patla AE, McGill SM. Low back three-dimensional joint forces, kinematics, and kinetics during walking. Clinical Biomechanics 1999; 14:203-216. Cappozzo A. Compressive loads in t he lumbar vertebral column during normal level walking. Journal of Orthopaedic Research 1984; 1:292-301. Capozzo A. The forces and couples in the human trunk during level walking. Journal of Biomechanics 1983; 16:265-277. Cromwell R, Schultz AB, Beck R, Warw ick D. Loads on the lumbar trunk during level walking. Journal of Orthopaedic Research 1989; 7:371-377. DiGiovine CP, Cooper RA, Wolf E, Fitzgerald SG, Boninger ML. Analysis of whole body vibration during manual wheelchair propulsion: a comparison of seat cushions and back supports for individuals without a disability. Assistive Technology 2003; 15(2): 129-144. Dolan P, Adams MA. Recent advances in lumbar spinal mechanics and their significance for modeling. Clinical Biomechanics 2001; 16 Supplement:S8-S16.

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76 Ehde DM, Smith DG, Czerniecki JM, Campbell KM, Malchow DM, Robinson LR. Back pain as a secondary disability in persons with lower limb amputations. Archive of Physical Medicine and Rehabilitation 2001; 82:731-734. Farfan HF, et al. The effects of torsion on the lumbar intervertebral joints: the role of torsion in the production of disc degeneration. Journal of Bone Joint Surgery 1970; 52S: 468. Freedman KB. Herniated Nucleus Pulposus(Slipped Disc). Back Pain Health Center, 2002.< Friberg O. Clinical symptoms and biomechnics of lumbar spine and hip joint in leg length inequality. Spine 1983; 8:643-651. Friberg O. Biomechanical significance of correct length of lower limb prostheses: a clinical and radiological study. Prosthetics and Orthotics International 1984; 8:124-129. Gilad I, Nissan M. A study of vertebra and disc geometric relations of the human cervical and lumbar spine. Spine 1986; 11(2): 154-157. Giles LGF, Taylor JR. Low back pain associated with leg length inequality. Spine 1981; 6:510-521. Gofton JP. Persistant low back pain and leg length disparity. Journal of Rheumatology 1985; 12:747-750. Goh JH, Thambyah A, Bose K. Effects of varying backpack loads on peak forces in the lumbosacral spine during walking. Clinical Biomechanics 1998; 13 Supplement:S26-S31. Gross RH. Leg length inequality: how much is too much? Orthopedics 1978; 1:307-310.

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77 Henriksen M, Lund H, Moe-Nilssen R, Bliddal H, Danneskiod-Samsoe B. Test retest reliabi lity of trunk accelero metric gait analysis. Gait and Posture 2003; 30:1-11. Inman VT, Ralston HJ, Todd F. Human Walking. Baltimore: Williams and Wilkins, 1981. Keller TS, Colloca CJ, Fuhr AW. In Viv o transient vibration assessment of the normal human thor acolumbar spine. Journal of Manipulative and Physiological Therapeutics 2000; 23:521-530. Khoo BC, Goh JH, Bose K. A bi omechanical model to determine lumbosacral loads during single stance phase in normal gait. Medical Engineering Physiology 1995; 17:27-35. Koeller W, et al. Biomechanical properties of human intervertebral discs subjected to axial dynamic compression influence of age and degeneration. Journal of Biomechanics 1986; 19(10): 807-816. Lee RY, Turner-Smith A. The influenc e of the length of lower-limb prosthesis on spinal kinematics. Archive of Physical Medicine and Rehabilitation 2003; 84:1357-1362. Lin HS, Liu YK, Adams KH. Mechanical response of the lumbar intervertebral joint under physiological (complex) loading. Journal of Bone and Joint Surgery 1978; 60-A(1): 41-55. Mansfield A, Lyons GM. The use of acclerometery to detect heel contact events for use as a sensor in FES assisted walking. Medical Engineering and Physics 2003; 25:879-885. Moe-Nilssen R. A new method for eval uating motor control in real-life environmental conditions. Part 1: The instrument. Clinical Biomechanics 1998; 13:320-327.

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78 Nachemson AL. Low back pain: Its etiology and treatment. Clinical Medicine 1971; Jan:18-23. Nordin M, Frankel VH. Basic Biomechanics of the Musculoskeletal System. Maryland:Lippincott Williams and Wilkins, 2001. Regan J. Cervical Disc Herniation. www.spinesource.com/back-paindisorders/cervical-dis c-herniation.html 5/05. Richeimer S. New Tec hnologies for Treating Sciatica and Back Pain. www.spineuniverse.com/ar ticle 1485.html. 5/05. Robinson JL, Smidt GL, Arora JS. Accele rographic, temporal, and distance gait factors in below-knee amputees. Pysical Therapy 1977;57:898-904. Smidt GL, Arora JS, Johnst on RC. Accelerographic analysis of several types of walking. American Journal of Physical Medicine 1971;50:285-300. Smith DG, Ehde DM, Legro MW, Reiber GE, del Aguila M, Boone DA. Phantom limb, residual limb and ba ck pain after lower extremity amputations. Clinical Orthopaedics and Related Research 1999; 361:29-38. Soukka A, Alaranta H, Tallroth K, Heli ovaara M. Leg length inequality in people of working age: the association be tween mild inequality and low back pain is questionable. Spine 1991; 16:429-431. White SC, Gilchrist LA, Wilk BE. Asymmetr ic limb loading with true or simulated leg-length differences. Clinical Orthopaedics and Related Reseacrh 2004;421:287-292. Whittle MW. Gait Analysis: an Introduction. Oxford: Butterworth-Heinemann, 2002.

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79 Yack HJ, Berger RC. Dynamic stability in elderly: identifying a possible measure. Journal of Gerontology 1993; 48:M225-230. Yamada H. Strength of Biological Materials. New York: Robert E. Krieger, 1973.

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80 Bibliography Aday LA. Designing and Conduction of Heal th Surveys, A Comp. Guide. San Francisco: Jossey-Bass, 1996. Author unknown. Gross Anatomy: The Gait Cycle. June 2005. www.upstate.edu/cdb/grossanat/limbs6.shtml 2000. Author unknown. Conventions for nam ing parts of the gait cycle. June 2005. http://moon.ouhsc.edu/dthomps o/gait/terms.htm March 2002. Bates B. A visual guide to physical examination. Hanada E, Kirby RL, Mitchell M, Swuste JM. Measuring leg-length discrepancy by the Iliac crest palpation and book correction method: reliability and validity. Archives of Physical Medicine and Rehabilitation 2001; 82:938942. Inman VT, Ralston HJ, Todd F. Human Walking. Baltimore: Williams and Wilkins, 1981. Keeling P. Is asymmetry in foot posture observed with LLD? Mann M, Glasheen-Wray M, Nyberg R. Therapist agreement for palpation and observation of iliac crest heights. Physical Therapy 1984; 3:334-338. McDowell I, Newell C. Measuring Health: A Guide to Rating Scales and Questionnaires. New York: Oxford University Press, 1996.

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81 Moe-Nilssen R, Helbostad JL. Interstride trunk accelera tion variability but not step width variability can differentiate between fit and frail older adults. Gait Posture 2005; 2:164-170. Neumann DA. Kinesiology of the Musculoskeletal System: Foundations for Physical Rehabiliatation. St. Louis: Mosby, Inc., 2002. Rosse C, Gaddum-Rosse P. Hollinsheads Text book of Anatomy. Philadelphia: Lippi ncott-Raven, 1997. Whittle MW. Gait Analysis: an introduction. Great Britain: ButterworthHeinemann, 2002.

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82 Appendices

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83 Appendix 1 Survey of Lower Limb Amputees University of South Florida School of Physical Education, Wellness, and Sport Studies Department of Biomedical Engineering Survey of Lower Limb Amputees The purpose of this survey is to determine the frequency of diffe rent types of pain among lower limb amputees who use a prosthesis. This survey should take about 10-15 minutes to complete and answers are strictly confidential. Your input is greatly appreciated. Directions: Please circle the answer that best applies to you and fill in the blank space when needed. 1. Age: _______________ 2. Body weight in pounds ( with prosthesis on): ___________ 3. Height in inches: ____________ 4. Gender a) Male b) Female 5. What is your pres ent occupation? _______________ 6. Are you currently taking any medication? a) Yes; List the medicati on and what it is used for. _______________________ b) No 7. What type of prosthesis do you use? (Circle all that apply) a) Below the knee (BK Trans-Tibial) b) Above the knee (AK Trans-Femoral) c) None of the above 8. What side of the body is your lower limb prosthesis on? a) Left b) Right c) Both d) Not applicable

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84 Appendix 1 (Continued) 9. Do you use any other type of prosthesis? a) Yes; What type is it? _____________ b) No 10. What is the name of the manufacturer of the major parts of your prosthesis? Not the prac titioner or facility where you were fit. _________________________ 11. What is the weight of your prosth esis? _______________ 12. What was the date of your amputation? If born without the limb put birth date.(month/year)____________ 13. What was the date you were fitted for and started using your prosthesis? (month/year)____________ 14. While you are awake, what per centage of the time do you wear your prosthesis? a) 0-25% b) 26-50% c) 51-75% d) 76-100% 15. What is the longest time you are able to stand still using your prosthesis? a) Up to 5 minutes b) 6 -10 minutes c) 11-20 minutes d) 21-45 minutes e) 46 minutes or more 16. What is the reas on for your amputation? a) Medical condition other than cancer (Disease e.g., diabetes, vascular disease, etc.) b) Injury (Trauma) c) Congenital (B orn without limb) d) Cancer (Tumor) e) Other_________________

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85 Appendix 1 (Continued) 17. Circle the best response fo r your activity level before us ing a prosthesis (if applicable). a) Activity restricted to daily livi ng functions (eating, bathroom, etc.) b) Daily living functions and some community involvement c) Participation in community, voca tional (job), therape utic, and exercise activities d) Participation in high impact, stress or energy activities (i.e. running, cycling, team sports, etc.) e) No activity (used a caretaker) 18. Circle the best response for your ac tivity level since using a prosthesis. a) Increased since obtaining a prosthetic b) Decreased since obt aining a prosthetic c) Remained the same since obtaining a prosthetic 19. What is your activity level now? a) Walking but restricted to leve l surfaces in and around the house b) Walking with the ability to go up curbs, stairs, etc. around the community c) Participation in vocational (job) therapeutic (heali ng), or exercise activities d) Participation in activities that exhibit high impact, stress or energy levels e) No walking or activity ev en with the aid of a prosthesis 20. How many days a week (0-7) do you participate in the following activities? Swimming_____________ Weight Training________ Running_______________ Golf__________________ Other_________________ 21. How satisfied are you with your prosthesis? a) Very satisfied b) Satisfied c) Neither satisfied or dissatisfied d) Dissatisfied e) Very dissatisfied

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86 Appendix 1 (Continued) 22. How satisfied were you with lif e in general before becoming an amputee? a) Very satisfied b) Satisfied c) Neither satisfied or dissatisfied d) Dissatisfied e) Very dissatisfied 23. How satisfied are you with life in general after becoming an amputee? a) Very satisfied b) Satisfied c) Neither satisfied or dissatisfied d) Dissatisfied e) Very dissatisfied 24. What do you consider as t he main reason why you do not use your prosthesis? __________________ ____________________ 25. Do you use any other device to a ssist you in walking? (i.e. cane, walker, crutches) a) Yes; What is it? __________________ b) No 26. Do you experience back pain? a) Yes b) No 27. Do you have a medi cal condition or injury other than your amputation [scoliosis (curving of the spine to the si de), lordosis (forward curving of the spine), car accident] that causes you to have back pain? a) Yes; What is the conditi on?__________________ b) No 28. Rate the level of back pain you experience. 0 1 2 3 4 5 N/A Litt le pain Severe Pain 29. Where is the ba ck pain located? ______________________

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87 Appendix 1 (Continued) 30. Describe the natur e of the back pain your experience. (i.e. throbbing, piercing, etc.) ________________________ _____________ 31. In the last 4 weeks how often have you experienced back pain? a) Once or twice b) A few times c) Fairly often d) Very often e) Every day f) Not applicable 32. How much does the pain you experi ence interfere with the following things? Use the scale below: 1) Not at all 2) A little bit 3) Moderately 4) Quite a bit 5) Extremely 6) Not applicable a) Your ability to walk or move abou t __________ b) Your sleep __________ c) Your normal work __________ d) Your recreational activities __________ e) Your enjoyment of life __________ 33. Are you currently seeing a specia list specifically for the back pain other than your general practitioner? (i.e. ch iropractor, rehabilitation specialist, surgeon, etc.) a) Yes; What kind? _________________ b) No 34. Do you experience hip pain? a) Yes b) No 35. Rate the level of hip pain you experience. 0 1 2 3 4 5 N/A Litt le pain Severe Pain

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88 Appendix 1 (Continued) 36. Do you experience phantom pain(actual pain)? a) Yes b) No 37. Rate the level of phantom pain you experience. 0 1 2 3 4 5 N/A Litt le pain Severe Pain 38. Do you experience phantom sensati on(like pins and needles or like the limb is still there)? a) Yes b) No 39. Rate the level of phant om sensation you experience. 0 1 2 3 4 5 N/A Litt le pain Severe Pain 40. Do you experience any pain in the leg that has not been amputated? a) Yes b) No c) Not applicable Thank you for completing the survey. Your input is greatly appreciated. If you have any questions or concerns you can contact the following people: Tracy Perrotti (813) 787-1246 uftray12@aol.com

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89 Appendix 2 Control Group Survey University of South Florida College of Engineering Department of Chemical Engineering/Biomedical Engineering Survey of Back Pain The purpose of this survey is to dete rmine the prevalence of back pain among the general population. The survey should take about 10-15 minutes to complete and answers are strictly confidential. Your input is greatly appreciated. Directions: Please circle the answer that best applies to you and fill in the blank space when needed. 1. Age: __________________ 2. Body weight in pounds: _________________ 3. Height in inches: _____________________ 4. Gender a) Male b) Female 5. What is your present occupation? ___________________ 6. Are you currently taking any medication? a) Yes; List the medication and what it is used for.___________________ b) No 7. Circle the best response for your activity level. a) Activity restricted to daily livi ng functions (eating, bathroom, etc.) b) Daily living functions and some community involvement. c) Participation in community, vo cational (job), therapeutic, and/or exercise activities. d) Participation in high impact, st ress or energy activities ( i.e. running, cycling, team sports, etc.) e) No activity ( use a caretaker) 8. How many days a week (0-7) do you par ticipate in the following activities? Swimming_____________ Weight Training_________ Running_______________

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90 Appendix 2 (Continued) Golf___________________ Other__________________ 9. How satisfied are you with life in general? a) Very satisfied b) Satisfied c) Neither satisfied or dissatisfied d) Dissatisfied e) Very dissatisfied 10. Do you experience back pain? a) yes b) No 11. Do you have a medical condition or inju ry (scoliosis, lordosis, car accident etc.) that causes you to have back pain? a) Yes; What is the condition?__ _________________ b) No 12. Rate the level of back pain you experience. 0 1 2 3 4 5 N/A Little Pain Severe Pain 13. Where is the back pain located? ___________________ 14. Describe the nature of the back pain you experience. (i.e. throbbing, piercing, etc.) __________________ _______________ 15. In the last 4 weeks how o ften have you experienced back pain? a) Once or twice b) A few times c) Fairly often d) Very often e) Every day f) Not applicable

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91 Appendix 2 (Continued) 16. How much does the pain you expe rience interfere with the following things? Use the scale below: 1) Not at all 2) A little bit 3) Moderately 4) Quite a bit 5) Extremely 6) Not applicable a) Your ability to walk or move about __________ b) Your sleep __________ c) Your normal work __________ d) Your recreational activities __________ e) Your enjoyment of life __________ 17. Are you currently seeing a specialist specifically for the back pain other than your general practitioner? (i.e. ch iropractor, rehabilitation specialist, surgeon, etc.) a) Yes; What kind? __________________ b) No 18. Do you experience hip pain? a) Yes b) No 19. Rate the level of hip pain you experience. 0 1 2 3 4 5 N/A Little Pain Severe Pain Thank you for completing the survey. Your input is greatly appreciated. If you have any questions or concerns y ou can contact the following people: Tracy Perrotti (813) 787-1246 William E. Lee, Ph.D. (813) 974-2136

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92econds Appendix 3 G-Link Acceler ometer Specifications On-Board Accelerometers Triaxial MEMS accelerometers Analog Devices' ADXL2XXJE Acceleration Range +/2 G's or +/10 G's Shock Limits 500 G's Data Acquisition Modes Mode 1: autotrigger, user spec ified as a programmable output voltage from a specific channel Mode 2: on command from RS-232 or RF link Mode 3: transmit continually for pre-programmed time period DAS Software Windows 95/98/2000/XP, PC compatible Analog to Digital (A/D) Converter Successive approximation type, 12 bits resolution Data Storage Capacity 2 megabytes (approximately 1 million data points), 8 megabytes optional Datalogging Sample Rate Programmable, from 32 to 2048 sweeps/second (one sweep represents one sample from all active channels) Continuous Transmission Sample Rate 1000 sweeps of all three channels per second Data Sample Duration Programmable from 1 to 65,535 data sweeps; for 2048 sweeps per second, sample duration is 32 s G-Link Node Input Power 3.6 volt lithium ion AA size internal battery recommended, 2400 milliamp-hour capacity standard; or customer may supply external power from 3.1 to 9 volts G-Link Battery Lifespan 273 hours (estimated, using 80% @ 6 milliamps current draw and sensor RF receive link active, 20% @ 20 milliamps w/ sensor RF transmit link active) Radio Frequency (RF)Transceiver Carrier 916 MHz, narrowband, FCC compliant, license free use in USA Range for Base Station RF Trigger 100 feet (30 meters) typical, line of sight Range for Bi-Directional RF Link 100 feet typical, line of sight RF Programming and Downloading 19200 baud, wireless RF, pulse code modulated, ASK RS-232 Programming and Downloading 38400 baud direct serial RS-232 cable w/ miniature connector G-Link Sensor Transceiver PCB Size 25 mm by 25 mm by 5 mm Base Station Enclosure Size 110 mm by 75mm by 25 mm Operating Temperature -40 to +85 degrees Celsius

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Appendix 4 Information Cover Sheet Information for People Who Take Part in the Survey for an Investigation into the Prevalence of Back Pain in Lower Limb Amputees The following information is being presented to help you decide whether or not you want to take part in a minimal risk research study. Please read this carefully. If you do not understand anything, ask the person in charge of the study. Title of Study: Investigation into the Prevalence of Back Pain in Lower Limb Amputees Principal Investigator: Tracy A. Perrotti Study Location(s): University of South Florida You are being asked to participate because you are an amputee. General Information about the Research Study The purpose of this research study is to determine the prevalence of back pain among lower limb amputees who use a prosthesis. The information collected and the results obtained will be used to complete a masters thesis requirement and may be published. Plan of Study You will be required to complete a 40-question survey and return it in the enclosed self addressed stamped envelope. The survey should take between 10-15 minutes to complete. Payment for Participation No funds are available for this study. None of the people involved in the study, including the researchers, will be paid. Benefits of Being a Part of this Research Study By taking part in this research study, you may increase our overall knowledge of the prevalence of back pain among amputees. This information may help improve the design of new prostheses and the rehabilitation processes. There are no immediate benefits to you. Risks of Being a Part of this Research Study There are no risks involved in participating in this study. Confidentiality of Your Records Your privacy and research records will be kept confidential to the extent of the law. Authorized research personnel, employees of the Department of Health and 93

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94 Appendix 4 (Continued) Human Services, and the USF Instituti onal Review Board may inspect the records from this research project. The results of this study may be publis hed. However, the data obtained from you will be combined with data from others in the publication. The published results will not include your name or any other information that would personally identify you in any way. The results of this study will be used to m eet a masters thesis requirement. Only those involved with the thesis will have a ccess to the information obtained from you. Volunteering to Be Part of this Research Study Your decision to participate in this resear ch study is completely voluntary. You are free to participate in this research study or to withdraw at any time. There will be no penalty or loss of benefits you are entitled to receive, if you stop taking part in the study. Questions and Contacts If you have any questions about this research study, contact: Tracy Perrotti (813) 787-1246 If you have questions about your rights as a person who is taking part in a research study, you may contact the Division of Research Compliance of the University of South Florida at (813) 974-5638.

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95 Appendix 5 Excel Spreadsheet of Amputee Survey Results Subject # Age (years) Weight (lbs) Height(in) Gender Occupation Take Medication? Med 1 Med 2 1 52 272 77 m a a f 2 36 200 74 m g b 3 37 137 60 f f a a 4 27 105 56 f g b 5 66 165 67 m b a h l 6 41 156 65 f h b 7 81 123 70 m b a n l 8 63 106 63.5 f f a b i 9 44 190 78 m b 10 78 195 69 m b a m g 11 55 66 f e a l j 12 56 150 67 f ss a 13 88 160 69 m b a h f 14 70 62 f b a 15 83 217 62 f b a p q 16 55 120 61 f a i h 17 37 155 66.5 f c a b 18 51 155 67 m a a q g 19 29 115 62 f e b 20 56 203 73 m d b 21 58 171 71 m b a f f 22 46 175 72 m h b 23 36 289 f i b 24 44 290 70 m f a g 25 27 123 68 m i a c c 26 59 245 78 m a a o g 27 58 260 70 m h a h 28 35 140 62.5 f g a j 29 22 140 64 f d b j j 30 33 133 69 f c b 31 39 190 67 m i b 32 47 185 57 m b a d h 33 55 165 m e b 34 39 107 62 f f a i k Note: See Appendix 1 for surv ey questions and answers. Answer Key included at end of Appendix 5.

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96 Appendix 5 (Continued) Subject # Age (years) Weight (lbs) Height(in) Gender Occupation Take Medication? Med 1 Med 2 35 54 170 64 f h a n 36 52 275 75 m i a j j 37 81 110 58 f b a d q 38 49 285 m i a f 39 50 200 65 f i a q f 40 15 133 57 m d b f 41 35 140 68 f a a a 42 35 207 70 m i b 43 50 167 61 f a a p f 44 37 210 75 m i a j 45 40 125 36 m h b 46 60 165 70 m b b 47 44 145 65 f i b 48 56 200 75 m g a i h 49 45 139 67 f g a j 50 42 190 60 m h a m q 51 74 299 70 m b a n 52 56 320 74 m b a l n 53 66 225 76 m b a d q 54 83 185 75 m b a 55 58 256 76 m a a o j Note: See Appendix 1 for surv ey questions and answers. Answer Key included at end of Appendix 5.

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97 Appendix 5 (Continued) Subject # Med 3 Type of Prosthesis Side Prosthesis is on Use any other Prosthesis? Manufacturer Weight (lbs) prosthesis Date of Amputation Date Fitted 1 a b b a 8 Jan-99 Jun-99 2 b a b b 5 May-04 Jul-04 3 a b b Jan-80 Jan-80 4 b b b c 6 Feb-77 Apr-78 5 b a b c 10 Mar-97 Jun-98 6 a b b d 3.5 Mar-85 Jun-86 7 q b a b Mar-04 Mar-04 8 a b b 2.5 Jan-90 Mar-90 9 a b e 2 Jul-04 Apr-04 10 l b c b 11 g a b b e 3 Nov-98 Jan-98 12 b a b 7 Jan-91 Jan-92 13 f b b b 9 Oct-84 Apr-85 14 b a b Aug-04 15 q a b a 16 j b c b 60 Dec-77 Jul-81 17 b a b n 8 Apr-78 May-78 18 b c b c 10 Apr-03 Oct-03 19 b b b 8 Jan-77 Jan-77 20 a c a a 4.5 Feb-00 Jun-00 21 a a,b c b c 13 Mar-04 mar-01, may-01 22 b a a a 11 Aug-84 Nov-84 23 b b b c 15 Oct-02 Oct-02 24 a a b f 5 Oct-00 Jan-01 25 b b b g,c 8 Nov-96 Aug-98 26 b a b 8 Oct-03 Nov-03 27 b b g 15 Sep-94 Dec-94 28 a a b c 4 Jan-70 Nov-05 29 b b b g Jan-83 30 a a b i 5 Jan-76 July-76 31 b b j Jan-85 Jan-87 32 a b b 8 Mar-04 May-04 33 a b b 6 Feb-00 Jan-60 34 k a a b k 4 Sep-02 Jan-03 Note: See Appendix 1 for surv ey questions and answers. Answ er Key included at end of Appendix 5.

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98 Appendix 5 (Continued) Subject # Med 3 Type of Prosthesis Side Prosthesis is on Use any other Prosthesis? Manufacturer Weight (lbs) prosthesis Date of Amputation Date Fitted 35 a b b c 5 Feb-03 Apr-04 36 g a c b july-99, jun01 sept-01 37 i a a b 6 Feb-93 Aug-93 38 a b b Jul-04 Sep-04 39 a b b 14 Dec-92 Apr-93 40 a b b c 4 Jul-89 Mar-90 41 b b b Jun-69 May-05 42 a b b g 3 Oct-01 Dec-01 43 a b b 6 Oct-04 Jan-04 44 a,b c b c 17 Mar-98 Mar-99 45 c d b May-99 46 b a b c,m 6.5 Feb-96 Mar-96 47 a a b d 4 Jun-87 Oct-87 48 m a a b 12 Jul-73 Jan-74 49 b a b c 10 Mar-00 Jun-00 50 b a b c,g 9 Aug-90 Sep-90 51 a a b n 14 Nov-55 Feb-56 52 a a b May-02 Jul-02 53 f a b a Aug-02 Nov-02 54 a b b Apr-97 Nov-97 55 l a a b g 10 Jul-03 Jan-03 Note: See Appendix 1 for surv ey questions and answers. Answ er Key included at end of Appendix 5.

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99 Appendix 5 (Continued) Subject # % of time use prosthesis Longest time able to use Reason for Amputation Activity Level before Prosthesis Activity Level Since using Prosthesis Activity Level Now How many days swim How many days weight train 1 d c a c b b 0 1 2 d e b c b c 1 0 3 d e a d a d 3 3 4 d e c d a c 1 2 5 c e a c b b 2 0 6 d e b d a d 0 6 7 c e a c c b 0 0 8 d e d c a c 0 0 9 c e a a b b 0 0 10 a a a c b e 0 0 11 d a a c b a 0 0 12 d c a d a b 0 0 13 d a a c b e 0 0 14 a b a a c e 1 0 15 a b 16 a a b a a a 3 0 17 d d d e a c 0 3 18 d c b d b a 1 7 19 d e c d 1 1 20 c d b c b b 1 5 21 c e e c a c 1 4 22 c e b d b c 2 3 23 b c b a a a 3 3 24 d e b d b c 1 0 25 c b d d b b 0 0 26 c e b c b b 0 0 27 c d b b c b 0 0 28 d e e d 0 0 29 d e c c c d 0 2 30 d e b b c c 2 2 31 d c b b b b 0 0 32 d d a b a a 2 7 33 d e b d c d 0 2 34 d e a d b b 0 0 Note: See Appendix 1 for surv ey questions and answers. Answer Key in cluded at end of Appendix 5.

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100 Appendix 5 (Continued) Subject # % of time use prosthesis Longest time able to use Reason for Amputation Activity Level before Prosthesis Activity Level Since using Prosthesis Activity Level Now How many days swim How many days weight train 35 d c b b a b 0 0 36 d d a d b b 0 0 37 c e a b b b 0 0 38 c a b c a b 0 2 39 d c a a a b 0 0 40 c d c b a c 0 0 41 d b c b 0 2 42 d e b d c d 0 0 43 d c b b a b 0 3 44 a d b c b c 0 0 45 b d 0 2 46 c e a c b c 2 0 47 d c b d c d 0 3 48 d c b d b b 0 0 49 d e d c c c 0 0 50 c e b d b c 0 0 51 d e b c b 0 0 52 d d a b a b 0 0 53 a b e a c a 0 0 54 d e a c b a 0 0 55 a c a b b b 0 0 Note: See Appendix 1 for surv ey questions and answers. Answer Key included at end of Appendix 5.

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101 Appendix 5 (Continued) Subject # How many days run How many days golf How many days do other activity What is other Activity Satisfaction with Prosthesis Satisfaction with life before prosthesis Satisfaction with life after prosthesis Main reason do not use prosthesis 1 0 0 a b b d 2 0 0 5 e b a b a 3 0 0 0 d c a 4 0 0 2 b a a a b 5 0 0 7 b a b a 6 0 0 7 c b a a 7 0 0 0 a a b 8 0 0 7 a b a b 9 0 0 0 a a a 10 0 0 7 f a a b f 11 0 0 0 b a e 12 0 0 0 c b c 13 0 0 0 d a b c 14 0 0 0 c b c d 15 a b 16 0 0 0 d a d c 17 0 1 0 a e a 18 1 1 3 f b a c b 19 1 1 b a 20 1 1 7 a b a b 21 1 1 a b a f 22 1 1 5 a c a c d 23 1 1 b a b e 24 0 1 f a a b b 25 0 0 f d a b b 26 0 0 a a e 27 0 0 6 a d a b c,d 28 0 0 1,7 d,f a 29 1 0 b c a 30 0 0 b,f b a b 31 0 0 e c c e 32 0 0 f d b 33 0 0 d a b 34 0 0 c a d Note: See Appendix 1 for surv ey questions and answers. Answ er Key included at end of Appendix 5.

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102 Appendix 5 (Continued) Subject # How many days run How many days golf How many days do other activity What is other Activity Satisfaction with Prosthesis Satisfaction with life before prosthesis Satisfaction with life after prosthesis Main reason do not use prosthesis 35 0 0 b a b 36 0 0 b a e b,d 37 0 0 f c a d d 38 0 0 a a a 39 0 0 2 e c a d 40 0 0 c c c 41 0 0 b 42 0 0 2 c b b c 43 0 0 3 f d d b 44 0 0 b b e b 45 0 0 46 0 0 f e a b c 47 6 0 6 c,f a a b b 48 0 0 2 a b a b 49 0 0 b a a 50 0 1 c a a b,d 51 0 1 a a a 52 0 0 b a c 53 0 0 c a e c,d 54 0 0 e a 55 0 0 1 f d a d b,d Note: See Appendix 1 for surv ey questions and answers. Answ er Key included at end of Appendix 5.

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103 Appendix 5 (Continued) Subject # Use another assist device other assist device experience back pain Medical Condition that causes pain What is it Level of back pain Pain Location Nature of Pain 1 a a a b 4 f a 2 b b b 0 3 b a a 3 a,b b 4 b a a a 4 a b,c 5 a a a b 2 a c 6 b a a c 4 a c 7 a a b b 0 8 b a b 3 a b 9 b b b 0 10 a b b b 0 11 a a a b 4 a b,c 12 a a a b 4 c d 13 a a,b b b 0 14 a b a a d 3 c b,h 15 b 16 a a,b a b 3 a b 17 b b 0 18 a c a b 2 a b 19 b a b 3 a b 20 a c a b 2 a,d e 21 a a b b 1 22 b a b a e 23 a a a b 3 a b,f 24 b a b 2 a b,e 25 a c a b 1 a 26 a a b b 27 a a a b 2 a,d b 28 b a a e 3 a a,c 29 b a a e 1 a a 30 b b b 0 31 b a a c 5 a g 32 a a a b 4 f a,c 33 b a b 2 a h 34 a a b b 0 Note: See Appendix 1 for surv ey questions and answers. Answ er Key included at end of Appendix 5.

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104 Appendix 5 (Continued) Subject # Use another assist device other assist device experience back pain Medical Condition that causes pain What is it Level of back pain Pain Location Nature of Pain 35 b a b 1 a b 36 b a b 4 a b,h 37 a a a b 1 a a 38 a a a a a 4 a 39 b a b 5 a c 40 a d b b 1 41 b a b 4 a h 42 b b b 1 43 a b a a a,c 3 a c,f 44 b b b 0 45 b b b 46 a c b b 1 47 b b b 48 s c a b 2 a h 49 b a b 3 a 50 a c a b 2 a b 51 b b a f 4 h 52 a a a a 3 a a 53 b b a f 5 54 a a b 1 55 b b b 0 Note: See Appendix 1 for surv ey questions and answers. Answer Key included at end of Appendix 5.

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105 Appendix 5 (Continued) Subject # Pain in last 4 weeks Pain interfere with walking Pain interfere with sleep pain interfere with normal work Pain interfere with rec activities Pain interfere with enjoyment of life Seeing a specialist for back pain What kind of specialist 1 d 3 2 4 5 4 b 2 f 1 1 1 1 1 b 3 e 4 2 5 5 2 b 4 e 3 3 1 3 1 b 5 b 2 2 2 2 2 b 6 e 2 2 2 2 2 b 7 b 8 c 9 f 6 6 6 6 6 b 10 f 6 6 6 6 6 a a 11 d 5 1 5 6 5 b 12 c 4 1 3 1 1 b 13 f 6 6 6 6 6 b 14 c 0 3 0 3 0 b 15 f 3 16 d 3 4 4 4 4 b 17 f 6 6 6 6 6 b 18 a 1 3 2 1 3 a a 19 d 2 1 2 2 2 b 20 b 2 1 1 1 2 b b 21 1 1 1 1 1 b 22 c 2 2 2 3 3 b 23 c 4 2 5 4 3 b 24 d 2 1 2 2 2 b 25 b 2 1 2 2 2 a c 26 f 6 6 6 6 6 b 27 c 4 3 3 4 4 b 28 c 3 5 3 4 5 a a,b,d 29 b 2 1 1 2 1 b 30 f 1 1 1 1 1 b 31 e 4 2 2 5 5 a b 32 e 4 5 5 5 5 a b 33 e 2 1 2 2 2 b 34 f 6 6 6 6 6 b Note: See Appendix 1 for survey questions and answers. Answer Key included at end of Appendix 5.

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106 Appendix 5 (Continued) Subject # Pain in last 4 weeks Pain interfere with walking Pain interfere with sleep pain interfere with normal work Pain interfere with rec activities Pain interfere with enjoyment of life Seeing a specialist for back pain What kind of specialist 35 b 2 2 1 2 3 b 36 b 3 3 4 5 4 b 37 b 2 1 2 3 2 b 38 b 2 2 3 4 3 a a 39 e 5 5 5 5 5 b 40 2 1 2 2 2 b 41 c 4 3 4 4 4 b 42 a 1 2 1 1 2 b 43 e 3 5 3 2 2 a a,d 44 a 1 1 1 1 1 a 45 a 1 1 1 1 1 b 46 f 2 1 2 2 2 b 47 f 6 6 6 6 6 48 e 2 2 2 2 2 b 49 c 5 4 7 7 3 a a 50 c 1 2 2 2 2 b 51 a 4 2 4 4 4 b 52 d 2 2 6 2 2 b 53 f 1 1 1 1 1 b 54 f 6 6 6 6 6 b 55 f 1 1 1 1 1 b Note: See Appendix 1 for survey questions and answers. Answer Key included at end of Appendix 5.

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107 Appendix 5 (Continued) Subject # Experience hip pain Level of Hip Pain Experience phantom pain Level of Phantom Pain Experience Phantom Sensation Level of Phantom Sensation Pain in nonamputated Leg 1 b 0 a 4 a 4 a 2 b 0 a 1 a 4 b 3 a 3 a 4 b 0 a 4 a 4 b 0 b 0 a 5 b 0 a 3 a 3 b 6 a 4 b 0 b 0 c 7 a 3 a 3 a 2 b 8 9 a 2 a 2 b 2 b 10 b 0 a 1 a 1 c 11 b 0 a 4 a 4 b 12 b 0 a 5 b 0 a 13 b 0 a 4 a 4 b 14 a 1 a 5 a 5 b 15 a 4 a 5 b 16 b 0 b 0 b 0 b 17 b 0 a 1 a 3 b 18 a 1 b 0 a 2 c 19 b 0 b 0 b 0 b 20 b 1 a 3 a 3 c 21 b 0 b 0 a 3 c 22 a a a b 23 a 3 a 5 a 4 a 24 a 1 b 0 a 2 b 25 b 0 a 5 a 3 a 26 b b a 4 b 27 b a a 1 b 28 a 1 b 0 b 0 a 29 b 0 b 0 b 0 a 30 b 0 b 0 b 0 b 31 a 2 a 3 a 3 b 32 a 4 a 5 a 5 a 33 b 0 a 2 a 2 a 34 a 1 a 1 a 3 b Note: See Appendix 1 for surv ey questions and answers. Answ er Key included at end of Appendix 5.

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108 Appendix 5 (Continued) Subject # Experience hip pain Level of Hip Pain Experience phantom pain Level of Phantom Pain Experience Phantom Sensation Level of Phantom Sensation Pain in nonamputated Leg 35 b 1 a 4 a 4 b 36 b 0 a 1 a 2 c 37 a 1 a 2 a 3 b 38 a 3 a 6 a 5 a 39 a 5 a 4 a 4 a 40 a 3 a 2 a 2 a 41 a 5 b 0 b 0 a 42 b 0 a 1 a 4 b 43 a 4 a 5 a 5 b 44 b 0 a 3 a 1 c 45 b b a b 46 b 2 a 2 a 4 a 47 a a 5 b 48 a 2 a 2 a 2 a 49 a 3 a 3 a 3 b 50 b 0 a 2 a 2 a 51 a 4 a 4 b b 52 a 3 a 2 a 4 a 53 b 3 a 5 a 5 a 54 b 1 a 4 a 4 a 55 a 2 a 5 a 5 a Note: See Appendix 1 for surv ey questions and answers. Answer Key included at end of Appendix 5.

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109 Appendix 5 (Continued) Key for Survey Answers Occupations a) Disabled b) Retired c) Homemaker d) Student e) Teacher f) Nurse g) Administration/Managerial h) Professional i) Other Medications a) Anti-inflammatory b) Migraine c) Skin Care d) Circulation e) Cancer f) Pain g) Cholesterol h) Blood pressure i) Osteoporosis/arthritis j) Anxiety/depression k) Organ rejection l) Diabetes Reasons for Non-Prosthesis Use a) Fatigue b) Wounds/Sores/Skin Problems c) Doesnt Fit/ Bad fit d) Pain e) Cumbersome f) Other Other Assistive Devices a) Cane b) Walker c) Crutches d) Wheelchair e) Other Nature of Back Pain a) Piercing b) Ache c) Throb d) Stabbing e) Stiffness f) Burning g) Cramping Location of Back Pain a) Lower back b) Neck c) Sacroiliac d) Mid Back e) Between Shoulder Blades f) Above Hips Medical Condition that Causes Back Pain (other than amputation) a) Fracture/dislocation/deformation of hip or leg b) Diabetes c) Car accident d) Arthritis e) Scoliosis/spondylosis/lordosis Type of Specialist a) Chiropractor b) PT/rehab specialist c) Acupuncturist d) Surgeon Manufacturer a) Hanger b) CA Tech c) Otto Bock d) Flex Foot e) West Coast f) Ohio Willowood g) Ossur h) Mauch i) Seattle Light j) Brownsfield k) Elation l) Luxon m) Endolite Other Activities a) Walking b) Pilates/Yoga c) Cycling d) Team Sports e) Yard/House Work f) Other

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110 Appendix 6 Excel Spreadsheet of Survey Results for Controls Subject # Age Weight (pounds) Height (inches) Gender Occupation Take Medicines? Med 1 Med 2 1 50 165 63 f g b 2 46 210 70.5 m i b 3 38 160 71 m h b 4 24 120 60 f g a loestrin 5 57 170 69 m h a g 6 31 233 72 m d a q 7 48 234 73 m g b 8 22 160 68 m d b 9 26 119 63 f e a r 10 70 170 72 m b a h g 11 44 245 74 m e a j 12 24 140 63 f e b 13 31 108 62 f e a q 14 30 215 70 m e a h 15 31 124 64 f e a q 16 50 165 67 f d b 17 26 126 61 f e b 18 49 150 64 f e a q 19 39 186 72 m e b 20 54 180 65 f g b Note: See Appendix 2 for surv ey questions and answers. Answer Key included at end of Appendix 6.

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11130 Appendix 6 (Continued) Subject # Age Weight (pounds) Height (inches) Gender Occupation Take Medicines? Med 1 Med 2 21 24 120 67 f e a r 22 49 125 64 f e a q m 23 63 135 64 f e b 24 54 140 63 f e a q botox 25 19 235 70 m d b 26 18 145 72 m d a q q 27 18 136 66 f d b 28 46 168 69.5 f g a q 29 62 140 66 f g a h 30 51 175 68 f g a f q 31 31 190 69 m g b 32 46 275 75 m i a h 33 24 180 68.5 m d b 34 21 150 66 f d b 35 25 122 64 f d b 36 23 175 70 m d b 37 35 190 71 m d b 38 26 175 70 m d b 39 19 137 68 f g a q 40 19 125 64 f g b 41 225 72 m h a f 42 28 230 75 m h b 43 27 160 68 f g b 44 30 230 76 m h a h Note: See Appendix 2 for surv ey questions and answers. Answer Key included at end of Appendix 6.

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112 Appendix 6 (Continued) Subject # Med 3 Activity Level How many days a week do you swim? How many days a week do you weight train How many days a week do you run? How many days a week do you golf? How many days a week do you do another activity? What is the other activity? 1 c 0 0 0 0 5 2 c 0 0 0 0 2 home projects 3 c 0 2 2 0 0 4 c 0 0 0 0 0 5 b 0 0 0 0 0 6 b 1 0 0 0 4 walking 7 c 0 0 3 1 1 8 d 0 6 0 0 0 9 c 0 0 0 0 0 10 m c 0 7 0 0 7 walking 11 c 0 0 0 0 5 motorcycle 12 c 0 2 0 0 3 13 c 0 3 0 0 5 walking 14 c 0 0 0 0 3 15 c 0 0 0 0 3 dance 16 d 0 3 0 2 6 17 d 0 2 3 0 0 18 c 0 0 0 0 7 walk/bike 19 d 0 0 4 0 0 20 c 0 0 0 0 4 walking Note: See Appendix 2 for survey questions and answers. Answ er Key included at end of Appendix 6.

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113 Appendix 6 (Continued) Subject # Med 3 Activity Level How many days a week do you swim? How many days a week do you weight train How many days a week do you run? How many days a week do you golf? How many days a week do you do another activity? What is the other activity? 21 c 0 4 0 1 0 22 b 0 0 0 0 0 23 c 0 0 0 0 walking/gardening 24 b 0 0 0 0 7 25 d 0 0 1 0 1 football/fencing 26 a 0 0 0 0 1 27 a 0 1 0 0 2 28 c 0 0 0 0 2 tennis 29 c 0 0 0 0 4 walking 30 c 0 0 0 0 7 walking/cleaning 31 d 0.5 2 1 0 1 32 d 0 0 0 0 2 tennis,walk 33 a 0 0 0 0 0 34 c 0 2 4 0 0 35 c 0 0 0 0 0 36 d 0 4 7 0 7 37 d 0 3 3 0 tennis 38 d 3 2 39 b 0 0 0 0 0 40 c 0 0 3 0 0 41 c 0 0 0 0 0 42 a 0 0 0 0 0 43 c 0 0 0 0 0 44 d 0 0 3 0 0 Note: See Appendix 2 for surv ey questions and answers. Answer Key included at end of Appendix 6.

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114 Appendix 6 (Continued) Subject # Satisfaction with life Experience back pain? Do you have a medical condition that causes the pain? What is the medical Condition Level of back pain pain location nature of pain 1 b b b 0 2 c a b 1 a b 3 b b b 0 4 c a b 3 a a,b 5 a b b 1 6 a a b 2 a a 7 b a a d 2 a a 8 a b b 0 9 b b b 0 10 a b b 0 11 b a a d 4 a a 12 c b b 0 13 b b b 0 14 b b b 0 15 c a a e 2 a 16 a b b 0 17 b b a e 1 a a 18 b b b 1 a b 19 d a b 5 a c 20 b a b 1 a a Note: See Appendix 2 for survey questions and answers. Answer Key included at end of Appendix 6.

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115a a e,f 5 a,f d,f 25 a b b 0 26 b a b 1 a I 27 c b b 0 28 b b b 0 29 a a b 3 a j 30 b a a f 2 a,b a 31 b a a 2 a a 32 b a b 3 a b 33 c b b 0 34 b a a c 3 a a 35 b a b 4 d,e c 36 b b b 0 37 b a b 1 a a 38 a b b 1 39 b a a c 3 a,d c 40 b b b 0 41 b a b 1 a 42 a b b 0 43 a b b 0 44 a a b 2 a c Note: See Appendix 2 for survey questions and answers. Answ er Key included at end of Appendix 6. Appendix 6 (Continued) Subject # Satisfaction with life Experience back pain? Do you have a medical condition that causes the pain? What is the medical Condition Level of back pain pain location nature of pain 21 b b b 1 a a 22 a a a e 3 b b 23 a a b 2 a c 24 d

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116Appendix 6 (Continued) Note: See Appendix 2 for survey questions and answers. Answer Key included at end of Appendix 6.Subject # Pain in the last 4 weeks Pain interfere with walking Pain interfere with sleep Pain interfere with normal work Pain interfere with rec activities 1 f 6 6 6 6 2 a 1 1 1 1 3 f 6 6 6 6 4 c 2 2 1 1 5 f 1 1 1 1 6 a 1 2 1 1 7 a 1 2 1 2 8 f 1 1 1 1 9 f 1 1 1 1 10 f 6 6 6 6 11 a 5 4 5 5 12 f 6 6 6 6 13 f 14 f 1 1 1 1 15 b 2 3 3 2 16 f 6 6 6 6 17 a 1 1 1 1 18 a 1 2 1 1 19 d 0 0 0 2 20 a 1 1 1 1

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117 Appemdix 6 (Continued) Subject # Pain in the last 4 weeks Pain interfere with walking Pain interfere with sleep Pain interfere with normal work Pain interfere with rec activities 21 b 1 1 1 2 22 b 1 1 2 2 23 b 1 3 1 1 24 e 5 4 5 4 25 f 1 1 1 1 26 a 1 1 1 1 27 f 6 6 6 6 28 f 6 6 6 6 29 b 2 2 2 3 30 e 2 2 2 2 31 e 1 2 2 2 32 c 2 3 2 2 33 f 1 1 1 1 34 b 1 3 2 2 35 c 1 4 1 1 36 f 1 1 1 1 37 a 1 1 1 2 38 f 39 c 2 3 2 1 40 f 6 6 6 6 41 b 5 3 2 2 42 f 6 6 6 6 43 f 6 6 6 6 44 a 1 1 1 1 Note: See Appendix 2 for surv ey questions and answers. Answer Key included at end of Appendix 6.

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118 Appendix 6 (Continued) Subject # Pain interfere with enjoyment of life Seeing a specialist for the pain What kind of specialist Experience hip pain? Level of hip pain 1 6 b b 0 2 1 b b 0 3 6 b b 0 4 2 b b 0 5 1 b a 2 6 1 b b 0 7 1 a e a 2 8 1 b b 0 9 1 b b 0 10 6 b b 0 11 5 b b 0 12 6 b b 0 13 14 1 b b 0 15 3 b a 2 16 6 b a 1 17 1 b b 0 18 2 b a 2 19 0 b b 0 20 1 b b 0 Note: See Appendix 2 for survey questions and answers. Answ er Key included at end of Appendix 6.

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119 Appendix 6 (Continued) Subject # Pain interfere with enjoyment of life Seeing a specialist for the pain What kind of specialist Experience hip pain? Level of hip pain 21 2 b b 0 22 2 b b 0 23 1 a a b 0 24 5 a e a 5 25 1 b a 1 26 1 b b 0 27 6 b b 0 28 6 b b 0 29 3 b b 0 30 2 b b 0 31 3 b b 1 32 2 b b 0 33 1 b b 0 34 2 b b 0 35 1 b a 1 36 1 b b 0 37 1 b b 0 38 39 1 b b 0 40 6 b b 0 41 2 b b 2 42 6 a b 0 43 6 b b 0 44 1 b b 0 Note: See Appendix 2 for surv ey questions and answers. Answer Key included at end of Appendix 6.

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120 Appendix 6 (Continued) Key for Survey Answers Occupations j) Disabled k) Retired l) Homemaker m) Student n) Teacher o) Nurse p) Administration/Managerial q) Professional r) Other Medications m) Anti-inflammatory n) Migraine o) Skin Care p) Circulation q) Cancer r) Pain s) Cholesterol t) Blood pressure u) Osteoporosis/arthritis v) Anxiety/depression w) Organ rejection x) Diabetes Reasons for Non-Prosthesis Use g) Fatigue h) Wounds/Sores/Skin Problems i) Doesnt Fit/ Bad fit j) Pain k) Cumbersome l) Other Other Assistive Devices f) Cane g) Walker h) Crutches i) Wheelchair j) Other Nature of Back Pain h) Piercing i) Ache j) Throb k) Stabbing l) Stiffness m) Burning n) Cramping Location of Back Pain g) Lower back h) Neck i) Sacroiliac j) Mid Back k) Between Shoulder Blades l) Above Hips Medical Condition that Causes Back Pain (other than amputation) f) Fracture/dislocation/deformation of hip or leg g) Diabetes h) Car accident i) Arthritis j) Scoliosis/spondylosis/lordosis Type of Specialist e) Chiropractor f) PT/rehab specialist g) Acupuncturist h) Surgeon Manufacturer n) Hanger o) CA Tech p) Otto Bock q) Flex Foot r) West Coast s) Ohio Willowood t) Ossur u) Mauch v) Seattle Light w) Brownsfield x) Elation y) Luxon z) Endolite Other Activities g) Walking h) Pilates/Yoga i) Cycling j) Team Sports k) Yard/House Work l) Other

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121 Appendix 7 Excel Spreadsheet of Su rvey Results for Amputee Subjects Subject # 1A 2A 3A 4A Age 38 32 58 81 Weight (lbs) 145 205 146 125 Height (inches) 66 71 65 71 Gender m m f m Occupation clerk technician admin asst retired Take medicines? a a b a Med 1 zestril todamax Med 2 coomadin celebrex Med 3 Type of prosthesis a a a b Side its on a b b a Use any other proshesis b a b b Manufacturer micacorp genisus 2 cleg Weight of prostheis(lbs) 8.5 Date of amputation 31229 38047 18172 Date fitted 38444 38139 % of time using prosthesis d c d Longest time able to use it e e e Reason for amputation a b e Reason (other) snake bite Activity level before amp d d Activity level after c a a Activity level now d d c b Days a week for swimming 0 2 0 0 Days a week weight training 3 0 0 0 Days a week running 0 2 0 0 Days a week golf 0 0 0 0 Days a week other activity 3 7 4 0 Other activity stationary bike walking Satisfaction b a a a Satisfaction with life before a a a Satisfaction with life after b a b Reason for no use sleeping sleep/shower Other assist device b a b b Assistive device crutch Note: See Appendix 1 for ke y to survey answers.

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122 Appendix 7 (Continued) Experience back pain b a a Medical condition for back painb b b Medical condition Level of back pain 0 2 1 Location of back pain lower right lower back Nature of back pain constricting/crampthrobbing Pain in last 4 weeks f a a Pain interfere with a 6 1 1 Pain interfere with b 6 1 1 Pain interfere with c 6 2 1 Pain interfere with d 6 3 1 Pain interfere with e 6 2 1 Seeing a specialist for pain b b b b Type of specialist Experience hip pain b a b b Level of hip pain 0 2 0 Experience phantom pain b a b a Level of phantom pain 0 3 0 4 Experience phantom sensationb a a a Level of phantom sensation 0 2 1 3 Experience pain in nonamp legb a b b Note: See Appendix 1 for key to survey answers.

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123 Appendix 8 Excel Spreadsheet of Su rvey Results for Control Subjects Subject # 1C 2C 3C Age 20 32 35 Weight (lbs) 168 165 194 Height (inches) 65 68 71 Gender f m m Occupation student student student Taking medication b b b Med 1 Med2 Med3 Activity level c b d Days a week swim 0 0 0 Days a week weight train 0 2 1 Days a week run 0 0.5 1 Days a week golf 0 0 0 Days a week other activity 1 0 Other activity walking tennis Satisfaction b b b Experience back pain b b a Medical condition for back pain b b a Type of medical condition injury Level of back pain 0 0 5 Location of back pain lowerback Nature of back pain piercing Frequency of pain in last 4weeksf f f Pain interfere with a 6 1 4 Pain interfere with b 6 1 3 Pain interfere with c 6 1 2 Pain interfere with d 6 1 5 Pain interfere with e 6 1 5 Seeing a specialist for pain b b b Type of specialist Experience hip pain b b b Level of hip pain 0 0 0 Note: See Appendix 2 for key to survey answers.

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124 Appendix 9 Excel Spreadsheet of Maximum Acceleration Changes Subject N1 N2 N3 1A ML MR Diff ML MR Diff ML MR Diff amp nonamp amp nonamp amp nonamp 0.450771.04587 0.59511.319070.96297-0.35611.37757 0.77757 -0.6 1.089770.87027 -0.21951.704371. 00197-0.70241.37757 1.08487 -0.2927 1.377571.17267 -0.20491.640970. 98727-0.65371.36777 0.73857 -0.6292 1.431270.99707 -0.43421.197070. 59707-0.61.18727 0.91907 -0.2682 1.455570.88487 -0.57071.294670. 78247-0.51221.14827 0.85557 -0.2927 1.206870.82147-0.38541.51907 0.80687 -0.7122 nonamp amp nonampamp nonamp amp 2A 0.402670.64167 -0.2390.490470.89047-0.40.30997 0.60267 -0.2927 0.636770.93927 -0.30250.412370. 88067-0.46830.47097 0.83187 -0.3609 0.587970.88557 -0.29760.309970. 64167-0.33170.42707 0.77337 -0.3463 0.358770.54407 -0.18530.314870. 95877-0.64390.27097 0.68067 -0.4097 0.383170.75877 -0.37560.344070. 70507-0.3610.28067 0.66117 -0.3805 nonamp amp nonampamp nonamp amp 3A 0.381670.41577 -0.03410.225570 .23527-0.00970.43527 0.38647 0.0488 0.474370.24017 0.23420.308470.32797-0.01950.49867 0.33287 0.1658 0.342570.35237 -0.00980.313370. 274370.0390.41087 0.43527 -0.0244 0.391370.32797 0.06340.293870.284070.00980.49387 0.34257 0.1513 0.366970.30847 0.05850.391370.342570.04880.38647 0.32797 0.0585 0.39137 0.391370.371870.279170.0927 1C 0.46450.2694 0.19510.32790. 5718-0.24390.5962 0.445 0.1512 0.42060.323 0.09760.33280.5084 -0.17560.5669 0.4157 0.1512 0.45470.2694 0.18530.33280.4157 -0.08290.4742 0.4645 0.0097 0.46940.3133 0.15610.38640.4791 -0.09270.4938 0.4694 0.0244 0.24990.362 -0.11210.33280. 4889-0.15610.4742 0.3767 0.0975 0.34250.1864 0.15610.38640.5328 -0.14640.4108 0.3864 0.0244 0.20110.3035 -0.1024 2C 0.429640.23944 0.19020.571140 .322340.24880.48334 0.36624 0.1171 0.546740.25894 0.28780.395440.50764-0.11220.45894 0.27354 0.1854 0.302840.36624 -0.06340.419840.48814-0.06830.34184 0.29304 0.0488 0.605240.31254 0.29270.541840.302840.2390.49304 0.35644 0.1366 0.336940.33204 0.00490.571140.317440.2537 3C 0.412340.37324 0.03910.402540 .319640.08290.37324 0.34404 0.0292 0.495240.31964 0.17560.504940.3342 40.17070.45134 0.55864 -0.1073 0.553740.44154 0.11220.475740.3732 40.10250.36354 0.48064 -0.1171 0.353740.37324 -0.01950.514740. 412340.10240.38794 0.44154 -0.0536 0.35864 -0.358640.446440.412340.0341 Key: ML = peak acceleration change for the left leg N1, N2, N3 = normal walking trials 1,2,3 MR = peak acceleration change for the right leg A = amputee Diff = Difference between ML and MR C = Control

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125 Appendix 9 (Continued) Subject F1 F2 F3 1A ML MR Diff ML MR Diff ML MR Diff amp nonamp amp nonamp amp nonamp 1.11417 1.07997 -0.03421.421470.80687-0.61461.92877 1.15807-0.7707 1.93857 1.07027 -0.86831.226370.91417-0.31221.49467 1.35807-0.1366 2.32387 1.04097 -1.28291.440971.10437-0.33661.33367 1.11907-0.2146 1.86537 0.97757 -0.88781.065370.78727-0.27811.81657 0.80197-1.0146 1.93857 0.71417 -1.22441.201970 .85077-0.35120.70927 1.270270.561 2.24097 0.91907 -1.32191.582471.08977-0.4927 nonamp amp nonampamp nonamp amp 2A 0.68067 1.19777 -0.51710.524571 .16357-0.6390.47577 1.14897-0.6732 0.85137 1.55387 -0.70250.412371.23187-0.81950.38797 1.22707-0.8391 0.60747 1.81727 -1.20980.387970.66557-0.27760.67097 1.07577-0.4048 0.85137 1.09537 -0.2440.378270. 79287-0.41460.42707 1.12457-0.6975 0.42707 1.77337-1.77337 nonamp amp nonampamp nonamp amp 3A 0.54747 0.65967 -0.11220.215770 .42557-0.20980.31827 0.58167-0.2634 0.53287 0.43527 0.09760.479170.4791700.50847 0.52307-0.0146 0.68897 0.49867 0.19030.513370.6304 7-0.11710.43527 0.61087-0.1756 0.56217 0.46457 0.09760.557270. 552370.00490.58167 0.62067-0.039 0.59627 0.596270.464570.5230 7-0.05850.43047 0.420670.0098 1C 0.3425 0.4401 -0.09760.5133 0.5425-0.02920.5767 0.37670.2 0.4596 0.3816 0.0780.54250.5962-0.05370.4547 0.5035-0.0488 0.7718 0.7718 00.45470.5718 -0.11710.6547 0.44010.2146 0.6694 0.5279 0.14150.5620.8059-0.24390.6401 0.762-0.1219 0.484 0.6157 -0.13170.75230.8694 -0.11710.4499 0.5328-0.0829 0.5913 0.5913 2C 1.00034 0.95644 0.04391.405241. 097940.30730.86864 1.07844-0.2098 0.79544 1.17594 -0.38051.136940 .834540.30241.09304 1.073540.0195 0.68334 0.88814 -0.20480.927240 .722340.20490.74184 0.688140.0537 0.67354 0.673540.68334 0.556440.1269 3C 0.93424 0.86104 0.07321.124541. 18794-0.06341.24154 0.783040.4585 1.17324 1.71474 -0.54151.329341 .139140.19021.31964 1.63674-0.3171 1.50494 1.34884 0.15611.480641. 173240.30741.32934 1.290340.039 1.81714 -1.81714 1.54884-1.548841.34884 1.48064-0.1318 1.60744-1.60744 Key: ML = peak acceleration change for the left leg F1, F2, F3 = Fast walking trials 1,2,3 MR = peak acceleration change for the right leg A = amputee Diff = Difference between ML and MR C = Control

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126 Appendix 9 (Continued) Subject S1 S2 S3 1A ML MR Diff ML MR Diff ML MR Diff amp nonamp amp nonamp amp nonamp 0.343370.21657 -0.12680.284870.314170.02930.29947 0.28487-0.0146 0.177570.27027 0.09270.440970 .4409700.30437 0.28977-0.0146 0.197070.23607 0.0390.304370. 377570.07320.21657 0.245870.0293 0.250770.33367 0.08290.328770.2994 7-0.02930.33857 0.25077-0.0878 0.133670.26047 0.12680.255570.25077-0.00480.29467 0.358070.0634 0.148270.29947 0.15120.401970.3872 7-0.01470.41167 0.32877-0.0829 0.24587 0.245870.323870.2994 7-0.02440.47997 0.28487-0.1951 0.31907 -0.319070.32877 -0.32877 2A nonamp amp nonampamp nonamp amp 0.334370.39287 -0.05850.324570. 80747-0.48290.24167 0.63187-0.3902 0.270970.74897 -0.4780.192870.78797-0.59510.24657 0.74897-0.5024 0.344070.60267 -0.25860.300170. 80747-0.50730.24657 0.53927-0.2927 0.275770.60267 -0.32690.290470. 70507-0.41460.23187 0.60267-0.3708 0.534370.50507 0.02930.236770.9099 7-0.67320.19287 0.66117-0.4683 0.36357 0.36357 0.80747-0.80747 0 3A nonamp amp nonampamp nonamp amp 0.206070.39627 -0.19020.337770. 42067-0.08290.26457 0.35237-0.0878 0.269470.28897 -0.01950.230470.24997-0.01950.29867 0.284070.0146 0.240170.33777 -0.09760.264570.225570.0390.24997 0.31337-0.0634 0.235270.31337 -0.07810.279170.216970.06220.31337 0.32797-0.0146 0.303570.39627 -0.09270.352370.303570.04880.26947 0.30357-0.0341 0.123070.37187 -0.24880.16697 0.16697 0.30357-0.30357 1C 0.27910.1474 0.13170.27910. 4255-0.14640.4499 0.37670.0732 0.2840.2108 0.07320.34250. 27910.06340.5767 0.37180.2049 0.22060.3084 -0.08780.4303 0.2840.14630.3377 0.4157-0.078 0.21570.2694 -0.05370.33280. 18160.15120.3035 0.3377-0.0342 0.21080.3377 -0.12690.27420.4011 -0.12690.2742 0.3328-0.0586 0.3230.3523 -0.02930.27420.3035 -0.02930.3181 0.4986-0.1805 0.3230.3572 -0.03420.4352 0.4352 2C 0.493040.32234 0.17070.556440 .380840.17560.29794 0.283340.0146 0.375940.41504 -0.03910.429640.356440.07320.36624 0.351540.0147 0.410140.41014 00.678440. 327240.35120.51744 0.322340.1951 0.390640.30284 0.08780.493040.390640.10240.46374 0.341840.1219 0.42964 0.42964 0.30284-0.302840.44914 3C 0.329340.16844 0.16090.344040 .256240.08780.25624 0.33424-0.078 0.270840.17324 0.09760.480640.329340.15130.21234 0.32454-0.1122 0.509840.30494 0.20490.373240.290340.08290.17814 0.43674-0.2586 0.461040.46594 -0.00490.339140.197640.14150.18304 0.35864-0.1756 0.319640.31474 0.00490.368440.339140.02930.24644 0.44644-0.2 0.353740.20744 0.14630.387940.270840.11710.19274 0.39274-0.2 0.441540.22204 0.21950.319640.231840.0878

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127 Appendix 9 (Continued) Subject inch Right Leg On 1 inch Right Leg On 1A ML MR Diff ML MR Diff amp nonamp amp nonamp 1.026370.73857-0.28780.894670.95317 0.0585 1.489771.06537-0.42441.319071.00197 -0.3171 0.928771.177570.24881.182471.09467 -0.0878 0.616571.387270.7707 2A nonamp amp nonamp amp 0.270970.91967-0.64870.324571.35877 -1.0342 0.227071.08557-0.85850.158771.36847 -1.2097 0.227070.54407-0.3170.314871.90507 -1.5902 0.59287-0.59287 0.75877 -0.75877 3A nonamp amp nonamp amp 0.240170.176770.06340.298670.24997 0.0487 0.245070.25477-0.00970.493870.34257 0.1513 0.342570.245070.09750.386470.36217 0.0243 0.327970.264570.06340.352370.35727 -0.0049 0.20607-0.20607 0.45477 -0.45477 1C 0.11330.284-0.17070.20590.4645 -0.2586 0.25470.5035-0.24880.2840.5084 -0.2244 0.26450.3328-0.06830.24010.5669 -0.3268 0.24990.3425-0.09260.18160.3377 -0.1561 0.1669 0.1669 2C 0.302840.46864-0.16580.351540.15154 0.2 0.307640.46864-0.1610.371140.60524 -0.2341 0.400340.67354-0.27320.419840.66374 -0.2439 0.52234-0.52234 3C 0.295240.104940.19030.104940.35374 -0.2488 0.607440.314740.29270.275740.47574 -0.2 0.480640.236740.24390.422040.29524 0.1268 0.563540.544040.01950.461040.28544 0.1756 0.504940.353740.15120.397640.39274 0.0049 0.39274 0.39274 Key: ML = peak acceleration change for the left leg A = Amputee MR = peak acceleration change for the right leg C = Control Diff = Difference between ML and MR

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128 Appendix 9 (Continued) Subject inch Left Leg On 1 inch Left Leg On 1A ML MR ML MR amp nonamp amp nonamp 0.567771.011670.44390.714170.64587 -0.0683 1.050771.231270.18050.962971.27027 0.3073 0.694670.933670.2390.640971.29467 0.6537 1.15807 -1.158071.387270.51907 -0.8682 2A nonamp amp nonamp amp 0.485570.231870.2537 0.505070.55387-0.0488 1.007470.212370.7951 3A nonamp amp nonamp amp 0.313370.34747-0.03410.347470.28407 0.0634 0.420670.269470.15120.396270.30847 0.0878 0.337770.298670.03910.562170.33287 0.2293 0.313370.33777-0.0244 0.52307 -0.52307 Key: ML = peak acceleration change for the left leg A = Amputee MR = peak acceleration change for the right leg C = Control Diff = Difference between ML and MR

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129 Appendix 10 Excel Spreadsheet of Means and Standard Deviations Normal 1A N 2A N 3A N Trials Amp NonAmp Amp NonAmpAmp NonAmp For 0.45077 1.045870.641670.402670.41577 0.38167 Amputees 1.08977 0.870270.939270.636770.24017 0.47437 1.37757 1.172670.885570.587970.35237 0.34257 1.43127 0.997070.544070.358770.32797 0.39137 1.45557 0.884870.758770.383170.30847 0.36697 1.31907 0.962970.890470.490470.23527 0.39137 1.70437 1.001970.880670.412370.32797 0.22557 1.64097 0.987270.641670.309970.27437 0.30847 1.19707 0.597070.958770.314870.28407 0.31337 1.29467 0.782470.705070.344070.34257 0.29387 1.20687 0.821470.602670.309970.27917 0.39137 1.37757 0.777570.831870.470970.38647 0.37187 1.37757 1.084870.773370.427070.33287 0.43527 1.36777 0.738570.680670.270970.43527 0.49867 1.18727 0.919070.661170.280670.34257 0.41087 1.14827 0.85557 0.32797 0.49387 1.51907 0.80687 0.38647 Mean 1.302676 0.9003820.7597170.400050.325833 0.381058 Std Dev 0.275284 0.1427680.1316930.108550.056262 0.071953 Average of the Averages Amputess amp nonamp Difference avg 0.7960750.560497 0.235578 0.166579 std dev 0.4894360.294502

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130 Appendix 10 (Continued) Normal 1C N 2C N 3C N Trials Left Right Left Right Left Right For 0.4645 0.26940.429640.239440.41234 0.37324 Controls 0.4206 0.3230.546740.258940.49524 0.31964 0.4547 0.26940.302840.366240.55374 0.44154 0.4694 0.31330.605240.312540.35374 0.37324 0.2499 0.3620.336940.332040.40254 0.35864 0.3425 0.18640.571140.322340.50494 0.31964 0.2011 0.30350.395440.507640.47574 0.33424 0.3279 0.57180.419840.488140.51474 0.37324 0.3328 0.50840.541840.302840.44644 0.41234 0.3328 0.41570.571140.317440.37324 0.41234 0.3864 0.47910.483340.366240.45134 0.34404 0.3328 0.48890.458940.273540.36354 0.55864 0.3864 0.53280.341840.293040.38794 0.48064 0.5962 0.4450.493040.35644 0.44154 0.5669 0.4157 0.4742 0.4645 0.4938 0.4694 0.4742 0.3767 0.4108 0.3864 Mean 0.406205 0.3990210.464140.3383470.441194 0.395926 Std Dev 0.100679 0.1025250.0968450.0774510.064448 0.067609 Average Of The Averages Controls left right avg 0.437180.377765 std dev 0.0291750.034172

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131 Appendix 10 (Continued) Fast Trials 1A 2A 3A For Amp NonAmp Amp NonAmp Amp NonAmp Amputees 1.114171.079971.197770.680670.65967 0.54747 1.938571.070271.553870.851370.43527 0.53287 2.323871.040971.817270.607470.49867 0.68897 1.865370.977571.095370.851370.46457 0.56217 1.938570.714171.163570.524570.42557 0.59627 2.240970.919071.231870.412370.47917 0.21577 1.421470.806870.665570.387970.63047 0.47917 1.226370.914170.792870.378270.55237 0.51337 1.440971.104371.148970.427070.52307 0.55727 1.065370.787271.227070.475770.58167 0.46457 1.201970.850771.075770.387970.52307 0.31827 1.582471.089771.124570.670970.61087 0.50847 1.928771.158071.773370.427070.62067 0.43527 1.494671.35807 0.42067 0.58167 1.333671.11907 0.43047 1.816570.80197 0.709271.27027 Mean 1.5672411.0036881.2206080.5448390.530413 0.49547 Std Dev 0.4418740.178940.3314870.1716670.080676 0.115448 Average of the Averages Amputessamp nonamp Difference Avg 1.1060870.681332 0.424755 0.300347 Std dev 0.5278160.280257

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132 Appendix 10 (Continued) Fast Trials 1C 2C 3C For Left Right Left Right Left Right Controls 0.34250.44011.000340.956440.93424 0.86104 0.45960.38160.795441.175941.17324 1.71474 0.77180.77180.683340.888141.50494 1.34884 0.66940.52791.405241.097941.12454 1.81714 0.4840.61571.136940.834541.32934 1.18794 0.59130.54250.927240.722341.48064 1.13914 0.51330.59620.673541.078441.24154 1.17324 0.54250.57180.868641.073541.31964 1.54884 0.45470.80591.093040.688141.32934 0.78304 0.5620.86940.741840.556441.34884 1.63674 0.75230.37670.68334 1.29034 0.57670.5035 1.48064 0.45470.4401 1.60744 0.65470.762 0.64010.5328 0.4499 Mean 0.5574690.5825330.9099040.907191.27863 1.353009 Std Dev 0.1184060.1554350.2324870.2051710.169512 0.319152 Average of the Averages Controls left right Difference Avg 0.9153340.947578 -0.032240.0228 Std Dev 0.3606110.386822

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133 Appendix 10 (Continued) Slow Trials 1A 2A 3A For Amp NonAmp Amp NonAmp Amp NonAmp Amputees 0.343370.216570.392870.334370.39627 0.20607 0.177570.270270.748970.270970.28897 0.26947 0.197070.236070.602670.344070.33777 0.24017 0.250770.333670.602670.275770.31337 0.23527 0.133670.260470.505070.534370.39627 0.30357 0.148270.299470.807470.363570.37187 0.12307 0.284870.245870.787970.324570.42067 0.33777 0.440970.314170.807470.192870.24997 0.23047 0.304370.440970.705070.300170.22557 0.26457 0.328770.377570.909970.290470.21697 0.27917 0.255570.299470.807470.236770.30357 0.35237 0.401970.250770.631870.241670.35237 0.16697 0.323870.387270.748970.246570.28407 0.26457 0.319070.299470.539270.246570.31337 0.29867 0.299470.284870.602670.231870.32797 0.24997 0.304370.289770.661170.192870.30357 0.31337 0.216570.24587 0.30357 0.26947 0.338570.25077 0.294670.35807 0.411670.32877 0.479970.28487 0.32877 Mean 0.2992840.2988130.6788510.289220.318011 0.259117 Std Dev 0.0897090.0564690.135860.0828910.057775 0.057927 Average of the Averages Amputeesamp nonamp difference avg 0.4320490.282383 0.149665 std dev 0.2139420.020712 0.105829

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134 Appendix 10 (Continued) Slow Trials 1C 2C 3C For Left Right Left Right Left Right Controls 0.27910.14740.493040.322340.32934 0.16844 0.2840.21080.375940.415040.27084 0.17324 0.22060.30840.410140.410140.50984 0.30494 0.21570.26940.390640.302840.46104 0.46594 0.21080.33770.429640.380840.31964 0.31474 0.3230.35230.556440.356440.35374 0.20744 0.3230.35720.429640.327240.44154 0.22204 0.27910.42550.678440.390640.34404 0.25624 0.34250.27910.493040.302840.48064 0.32934 0.43030.2840.297940.283340.37324 0.29034 0.33280.18160.366240.351540.33914 0.19764 0.27420.40110.517440.322340.36844 0.33914 0.27420.30350.463740.341840.38794 0.27084 0.43520.37670.44914 0.31964 0.23184 0.44990.3718 0.25624 0.33424 0.57670.4157 0.21234 0.32454 0.33770.3377 0.17814 0.43674 0.30350.3328 0.18304 0.35864 0.27420.4986 0.24644 0.44644 0.3181 0.19274 0.39274 Mean 0.324230.3258580.4536760.3467250.3284 0.303275 Std Dev 0.0896610.0862920.0933690.0421910.098842 0.088827 Average of the Averages controls left right Difference Avg 0.3687690.325286 0.043483 std dev 0.0735610.02173 0.030747

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135 Appendix 10 (Continued) 1/2 inch long Amputees 1A 2A 3A Amp NonAmp Amp NonAmp Amp NonAmp 1.026370.738570.919670.270970.17677 0.24017 1.489771.065371.085570.227070.25477 0.24507 0.928771.177570.544070.227070.24507 0.34257 0.616571.387270.59287 0.26457 0.32797 0.20607 Mean 1.015371.0921950.7855450.2417030.22945 0.288945 std dev 0.3613480.270880. 2604090.0253460.039821 0.05386 Controls 1C 2C 3C Left Right Left Right Left Right 0.11330.2840.302840.468640.29524 0.10494 0.25470.50350.307640.468640.60744 0.31474 0.26450.33280.400340.673540.48064 0.23674 0.24990.3425 0.522340.56354 0.54404 0.50494 0.35374 Mean 0.22060.36570.336940.533290.49036 0.31084 Std dev 0.0717910.0953670. 0549580.0968660.138053 0.184231 Average of the Averages Amputessamp nonamp Difference avg 0.6767880.540948 0.135841 0.096054 std dev 0.404090.477978 Controls left right Difference avg 0.34930.403277 -0.05398 0.038167 std dev 0.1353040.115888

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136 Appendix 10 (Continued) 1 inch long Amputees 1A 2A 3A Amp NonAmp Amp NonAmp Amp NonAmp 0.894670.953171.358770.324570.24997 0.29867 1.319071.001971.368470.158770.34257 0.49387 1.182471.094671.905070.314870.36217 0.38647 0.75877 0.35727 0.35237 0.45477 mean 1.132071.0166031.347770.266070.35335 0.382845 std dev 0.2166420.0718760. 468350.0930510.072772 0.082369 Controls 1C 2C 3C Left Right Left Right Left Right 0.20590.46450.351540.151540.10494 0.35374 0.2840.50840.371140.605240.27574 0.47574 0.24010.56690.419840.663740.42204 0.29524 0.18160.3377 0.46104 0.28544 0.1669 0.39764 0.39274 0.39274 Mean 0.22790.4693750.380840.4735070.33228 0.36058 std dev 0.0471710.097290. 0351680.2803610.131783 0.077875 Average of the Averages Amputessamp nonamp difference avg 0.9443970.555173 0.389224 0.275223 std dev 0.52310.403854 Controls left right difference avg 0.3136730.434487 -0.12081 0.085428 std dev 0.0781490.064039

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137 Appendix 10 (Continued) 1/2 inch short Amputees 1A 2A 3A Amp NonAmp Amp NonAmp Amp NonAmp 0.567771.011670.231870.485570.34747 0.31337 1.050771.231270.553870.505070.26947 0.42067 0.694670.933670.212371.007470.29867 0.33777 1.15807 0.33777 0.31337 mean 0.867821.058870.3327030.6660370.313345 0.346295 std dev 0.28150.1543120. 1917840.2958510.036062 0.0509 Average of the Averages Amputessamp nonamp Difference avg 0.5046230.690401 -0.18578 0.131365 std dev 0.3146870.356912 1 inch short Amputees 1A 2A 3A Amp NonAmp Amp NonAmp Amp NonAmp 0.714170.64587 0.28407 0.34747 0.962971.27027 0.30847 0.39627 0.640971.29467 0.33287 0.56217 1.387270.51907 0.52307 mean 0.9263450.93247 0.36212 0.435303 std dev 0.3367740.407569 0.109134 0.112547 Average of the Averages Amputessamp nonamp Difference avg 0.6442330.683887 -0.03965 0.02804 std dev 0.3989670.35155

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138 Appendix 11 Excel Spreadsheet of Delta Values Delta Values: Normal Trials 1A 2A 3A 1C 2C 3C 0.5951 -0.239 -0.0341 0.1951 0.1902 0.0391 -0.2195 -0.3025 0.2342 0.0976 0.2878 0.1756 -0.2049 -0.2976 -0.0098 0.1853 -0.0634 0.1122 -0.4342 -0.1853 0.0634 0.1561 0.2927 -0.0195 -0.5707 -0.3756 0.0585 -0.1121 0.0049 -0.35864 -0.3561 -0.4 0.39137 0.1561 0.2488 0.0829 -0.7024 -0.4683 -0.0097 -0.1024 -0.1122 0.1707 -0.6537 -0.3317 -0.0195 -0.2439 -0.0683 0.1025 -0.6 -0.6439 0.039 -0.1756 0.239 0.1024 -0.5122 -0.361 0.0098 -0.0829 0.2537 0.0341 -0.3854 -0.2927 0.0488 -0.0927 0.1171 0.0292 -0.6 -0.3609 0.0927 -0.1561 0.1854 -0.1073 -0.2927 -0.3463 0.0488 -0.1464 0.0488 -0.1171 -0.6292 -0.4097 0.1658 0.1512 0.1366 -0.0536 -0.2682 -0.3805 -0.0244 0.1512 -0.2927 0.1513 0.0097 -0.7122 0.0585 0.0244 0.0975 0.0244 Mean -0.40229 -0.35967 0.074392 0.007184 0.125793 0.013754 Std Dev 0.309437 0.105201 0.109683 0.141585 0.140591 0.140992 Neg 16 15 5 8 3 5 Pos 1 0 12 1 11 9 %Neg 94.11765 100 29.41176 42.10526 21.42857 35.71429

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139 Appendix 11 (Continued) Delta Values: Fast Trials 1A 2A 3A 1C 2C 3C -0.0342 -0.5171 -0.1122 -0.0976 0.0439 0.0732 -0.8683 -0.7025 0.0976 0.078 -0.3805 -0.5415 -1.2829 -1.2098 0.1903 0 -0.2048 0.1561 -0.8878 -0.244 0.0976 0.1415 0.3073 -1.81714 -1.2244 -0.639 0.59627 -0.1317 0.3024 -0.0634 -1.3219 -0.8195 -0.2098 0.5913 0.2049 0.1902 -0.6146 -0.2776 0 -0.0292 0.67354 0.3074 -0.3122 -0.4146 -0.1171 -0.0537 -0.2098 -1.54884 -0.3366 -0.6732 0.0049 -0.1171 0.0195 0.4585 -0.2781 -0.8391 -0.0585 -0.2439 0.0537 -0.3171 -0.3512 -0.4048 -0.2634 -0.1171 0.1269 0.039 -0.4927 -0.6975 -0.0146 0.2 -0.1318 -0.7707 -1.77337 -0.1756 -0.0488 -1.60744 -0.1366 -0.039 0.2146 -0.2146 0.0098 -0.1219 -1.0146 -0.0829 0.561 Mean -0.56355 -0.70862 0.000418 0.011344 0.085185 -0.36945 Std Dev 0.504443 0.412062 0.204697 0.200028 0.292187 0.779833 Neg 16 13 8 10 3 7 Pos 1 0 7 6 8 6 % Neg 94.11765 100 53.33333 62.5 27.27273 53.84615

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140 Appendix 11 (Continued) Delta Values: Slow Trials 1A 2A 3A 1C 2C 3C -0.1268 -0.0585 -0.1902 0.1317 0.1707 0.1609 0.0927 -0.478 -0.0195 0.0732 -0.0391 0.0976 0.039 -0.2586 -0.0976 -0.0878 0 0.2049 0.0829 -0.3269 -0.0781 -0.0537 0.0878 -0.0049 0.1268 0.0293 -0.0927 -0.1269 0.42964 0.0049 0.1512 0.36357 -0.2488 -0.0293 0.1756 0.1463 0.24587 -0.4829 -0.0829 -0.0342 0.0732 0.2195 0.0293 -0.5951 -0.0195 -0.1464 0.3512 0.0878 0 -0.5073 0.039 0.0634 0.1024 0.1513 0.0732 -0.4146 0.0622 0.1463 -0.30284 0.0829 -0.0293 -0.6732 0.0488 0.1512 0.0146 0.1415 -0.0048 -0.80747 0.16697 -0.1269 0.0147 0.0293 -0.0147 -0.3902 -0.0878 -0.0293 0.1951 0.1171 -0.0244 -0.5024 0.0146 0.4352 0.1219 0.0878 -0.31907 -0.2927 -0.0634 0.0732 -0.078 -0.0146 -0.3708 -0.0146 0.2049 -0.1122 -0.0146 -0.4683 -0.0341 -0.078 -0.2586 0.0293 -0.30357 -0.0342 -0.1756 -0.0878 -0.0586 -0.2 0.0634 -0.1805 -0.2 -0.0829 -0.1951 -0.32877 Mean -0.01344 -0.36671 -0.05562 0.014665 0.099636 0.025125 Std Dev 0.135522 0.276303 0.112554 0.14758 0.175208 0.146998 Neg 12 15 13 12 2 7 Pos 11 2 5 8 12 13 % Neg 52.17391 88.23529 72.22222 60 14.28571 35

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141 Appendix 11 (Continued) Delta Values: inch Long 1A 2A 3A 1C 2C 3C -0.2878 -0.6487 0.0634 -0.1707 -0.1658 0.1903 -0.4244 -0.8585 -0.0097 -0.2488 -0.161 0.2927 0.2488 -0.317 0.0975 -0.0683 -0.2732 0.2439 0.7707 -0.59287 0.0634 -0.0926 -0.52234 0.0195 -0.20607 0.1512 Mean 0.076825 -0.60427 0.001706 -0.1451 -0.28059 0.17952 Std Dev 0.546265 0.223055 0.122566 0.081779 0.169289 0.104258 Neg 2 4 2 4 4 0 Pos 2 0 3 0 0 5 %Neg 50 100 40 100 100 0 Delta Values: 1 inch Long 0.0585 -1.0342 0.0487 -0.2586 0.2 -0.2488 -0.3171 -1.2097 0.1513 -0.2244 -0.2341 -0.2 -0.0878 -1.5902 0.0243 -0.3268 -0.2439 0.1268 -0.75877 -0.0049 -0.1561 0.1756 -0.45477 0.1669 0.0049 0.39274 Mean -0.11547 -1.14822 -0.04707 -0.1598 -0.09267 0.041873 Std Dev 0.189322 0.348233 0.235379 0.192724 0.253504 0.241894 Neg 2 4 2 4 2 2 Pos 1 0 3 1 1 4 % Neg 66.66667 100 40 80 66.66667 33.33333

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142 Appendix 11 (Continued) Delta Values: inch short 1A 2A 3A 0.4439 0.2537 -0.0341 0.1805 -0.0488 0.1512 0.239 0.7951 0.0391 -1.15807 -0.0244 Mean -0.07367 0.333333 0.03295 Std Dev 0.731703 0.427549 0.085256 Neg 1 1 2 Pos 3 2 2 % Neg 25 33.33333 50 Delta Values: 1 inch Short -0.0683 0.0634 0.3073 0.0878 0.6537 0.2293 -0.8682 -0.52307 Mean 0.006125 -0.03564 Std Dev 0.653208 0.33308 Neg 2 1 Pos 2 3 % Neg 50 25