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Kuczynski, Ashley T.
The impact of wearable weights on perceptual responses to treadmill walking
h [electronic resource] /
by Ashley T. Kuczynski.
[Tampa, Fla] :
b University of South Florida,
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Thesis (M.A.)--University of South Florida, 2009.
Includes bibliographical references.
Text (Electronic thesis) in PDF format.
ABSTRACT: The growing public health burden associated with insufficient physical activity has resulted in the development of numerous health initiatives and products aimed at stabilizing and reversing the negative trends reported in epidemiological literature. A relatively novel product that has only recently made its way to the market are wearable weights. These products are designed to be worn on the lower legs and arms along with regular clothing as a means to increase caloric expenditure. However, no research to date has tested the efficacy of this product. PURPOSE: Compare psychological responses within bouts of aerobic exercise that vary on intensity and the presence of wearable weights. METHODS: Seventeen (11 female, 6 male, mean age = 24 years, mean BMI = 25.0 ) healthy volunteers were tested for aerobic fitness on a treadmill to determine VO2 max (mean = 44 ml x kg-1 x min-1).Participants then completed eight 30-minute walking trials on a treadmill while three ratings of perceived exertion (RPE overall, RPE chest and breathing, and RPE legs ) were monitored while walking at different speeds and with varying combination of upper and lower body wearable weights. The design included two intensities (slow walking and brisk walking) and four conditions (no weights, arm weights, leg weights, and arm and leg weights) for a total of eight experimental trials. RESULTS: Data were analyzed using ANOVA and pairwise comparisons. Analyses revealed RPE overall was significantly elevated (P < 0.05), as was RPE of the legs (p < 0.05) while wearing upper and lower weights in the brisk walk trial but not in the slow walk trial. CONCLUSIONS: Findings suggest that exercising while using wearable weights increases RPE for the legs and overall only during the faster walking trials.PRACTICAL APPLICATIONS: This finding suggests that physical activity associated with daily living could be enhanced through the wearing of weights that can be worn under clothing without increasing perceptions of effort. In contrast, findings relative to brisk walking suggest that any beneficial increase in energy expenditure is potentially offset by significantly increased effort.
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Advisor: Marcus Kilpatrick, Ph.D.
x Physical Education
t USF Electronic Theses and Dissertations.
The Impact of Wearable Weights on Pe rceptual Reponses to Treadmill Walking by Ashley T. Kuczynski A thesis submitted in partial fulfillment of the requirements for the degree of Master of Arts Department of Physical Education College of Education University of South Florida Major Professor: Marcus Kilpatrick, Ph.D. Bill Campbell, Ph.D. Candi Ashley, Ph.D. John Ferron, Ph.D. Date of Approval: April 6, 2009 Keywords: Perceived exertion, body togs, exerci se, physical activ ity, resistance Copyright 2009, Ashley Taree Kuczynski
i Table of Contents List of Tables ii List of Figures iii Abstract iv Chapter One Introduction 1 Rationale 1 Purpose 2 Objectives 6 Hypotheses 7 Limitations 7 Chapter Two Review of Literature 8 Chapter Three Methodology 14 Participants 14 Lab Trials 14 Screening (Visit 1) 15 Maximal Exercise Testing (Visit 2) 15 Workload Establishment and Familiarization (Visit 3) 16 Experimental Exercise Trials (Visits 4-11) 17 Protocol Description 18 Instrumentation 19 Research Design and Data Analysis 19 Inclusion/Exclus ion Criteria20 Chapter Four Results 21 Graded Exercise Testing 21 Self-Selected Speed 21 Rate of Perceived Exertion 22 RPE Overall 22 RPE Chest and Breathing 23 RPE Legs 25 Chapter Five Discussion 27 References 33
ii List of Tables Table 1 Description of Laboratory Visits 15 Table 2 Exercise Trial Conditions 18 Table 3 Rate of Percei ved Exertion Overall 23 Table 4 Rate of Perceived Ex ertion Chest and Breathing 24 Table 5 Rate of Percei ved Exertion Legs 25
iii List of Figures Figure 1. RPE Overall 23 Figure 2. RPE Chest and Breathing 25 Figure 3. RPE Legs 26
iv The Impact of Wearable Weights Per ceptual Responses to Treadmill Walking Ashley T. Kuczynski ABSTRACT The growing public health burden associated with insufficient physical activity has resulted in the development of numerous health initiatives and products aimed at stabilizing and reversing the negative trends reported in epidemio logical literature. A relatively novel product that has only recently made its way to the market are wearable weights. These products are designed to be worn on the lower legs and arms along with regular clothing as a means to increase caloric expenditure. However, no research to date has tested the efficacy of this product. PURPOSE: Compare psychological responses within bouts of aerobic exercise that vary on intensity and the presence of wearable weights. METHODS: Seventeen (11 female, 6 male, mean age = 24 years, mean BMI = 25.0 ) healthy volunteers were tested for aer obic fitness on a treadmill to determine VO2 max (mean = 44 ml x kg-1 x min-1). Participants then completed eight 30-minute walking trials on a treadmill while three ratings of perceived exertion (RPE overall, RPE chest and breathing, and RPE legs ) were monitored while walking at different speeds and with varying combination of uppe r and lower body wearable weights. The design included two intensities (slow walking and brisk walking) a nd four conditions (no weights, arm weights, leg we ights, and arm and leg wei ghts) for a total of eight experimental trials. RESULTS: Data we re analyzed using ANOVA and pairwise
v comparisons. Analyses revealed RPE overall was significantly elev ated (P < 0.05), as was RPE of the legs (p < 0.05) while wearing upper and lower weights in the brisk walk trial but not in the slow walk trial. CONCLUSIONS: Findings s uggest that exercising while using wearable weights increases RP E for the legs and overall only during the faster walking trials. PRACTICAL APPLICAT IONS: This finding sugg ests that physical activity associated with daily living could be enhanced through the wearing of weights that can be worn under clothi ng without increasing perceptions of effort. In contrast, findings relative to brisk walking suggest that any beneficial increase in energy expenditure is potentiall y offset by significantly increased effort.
1 Chapter One Introduction Rationale The current state of health in this nati on is a crisis of great consequence and one that must be altered. Specifically, the preval ence of obesity is a problem of monumental proportion. While obesity alone is an epidem ic, the sedentary lifestyle that equally prevails is a condition that will only ex acerbate present circumstances. One solution remains and has the capabilities to resolve both dilemmas. Increased energy expenditure through exercise serves to assist with the el imination of the obese and sedentary lifestyle epidemics. Reputable organizations, political figures and the surgeon general have all recommended and encouraged physical activity. Yet, the recommendations set forth and the impinging detriment that will ensue due to physical inactivity have not been catalysts to increase physical activity. The existence pr acticed by humans in days gone past is one that required larger amount s of energy expenditure. However, the technological advancements implemented within modern day society have eliminated the majority of the physical demands that were once imposed. Th erefore, the current cr isis presents that physical activity must be orchestrated back into the lives of every individual. The especially low rates of physic al activity participation among Americans clearly indicate that exercise is likely viewed as unimpor tant, inconvenient and unpleasant. Exercise alone can resolve the low en ergy expenditure issue, yet new and innovative methods to
2 increase exercise participation are imperative, that exercise may b ecome more appealing and beneficial (Pollo ck, et al., 1998). Purpose An abundance of physiological and psychol ogical benefits are provided by regular engagement in physical activity. Despite the excessive benefits exercise provides, the majority of adult Americans live a sedent ary and overweight/obese existence. Current epidemiological data attest to this reality. A sedentary lifestyle has revealed itself to be the most prevalent risk factor for premature mortality. Epidemiological data also support that a physically inactive lifes tyle is among the leading th ree causes of death in the United States. While it is common knowledge th at exercise is a vital component to a healthy lifestyle, this knowle dge has not changed behavior. Thus, the present epidemic has presented itself to the nation and has pr oduced the existing health crisis. In 1995, the Centers for Disease Control and Prevention al ong with the American College of Sports Medicine collaborated a nd produced physical activity recommendations. These recommendations were published with the hope th at they would improve the health of the public. The intention of the instruction formulated in 1995 by these two organizations was to provide clear and concise exercise recommendations. The Centers for Disease Control and Prevention and the American Coll ege of Sports Medicine understood that the public had a misperception of the mode and in tensity of the exercise that would produce health benefits. The public health message pr ovided by these organizations was set forth to communicate how much and what kind of exer cise to do and to pr ovide leadership to the public in this area. Prior to the ex ercise recommendations of 1995, many people
3 assumed that exercise had to be both vigor ous and continuous in order to bring about health benefits. The CDC and ACSM provi ded recommendations that refuted this assumption. Every US adult should accumula te 30 minutes or more of moderateintensity physical activity on most, preferably all, days of the week (Russell, 1995, p. 404). This instruction was supported by an abundance of epidemiological data, which attested to how moderate intensity exercise is also of great benefit. Thus, the movement to increase physical activity participation began by altering previous recommendations with the hope that the new and more a ttainable recommendations would cause an increase in physical activity participation. While the reco mmendations in 1995 elicited a movement towards more practical and achievabl e exercise guidelines, the efforts of the CDC and ACSM failed to provoke the public to become more physically active. The 1995 recommendations set the stage for a shift in the exercise guidelines (Pate, et al., 1995). In 2005, one decade af ter the CDC and ACSM physi cal activity recommendation, a collection of data revealed that nearly one-quarter of a dults in the United States reported no leisure-time physical activity. This data from 2005 al so attested that less than half of adults in the United States met the exercise recommendation provided in 1995. Epidemiological data offers further reason as to why it is essential for individuals to lead physically active lifestyles. Wh ile the majority of Americans are sedentary, the majority of Americans are also overweight/obese. A sedentary lifestyle places an individual at increased risk of developing di seases such as cardiovascular disease and cancer, both of which are leading causes of death. A physica lly active lifestyle serves as disease prevention and provides greater quality of life (Haskell, et al., 2007).
4 In 2007 the American College of Sports Medicine and the American Heart Association created revised exer cise guidelines that would fu rther the objec tives of the CDC and ACSM as provided in 1995. The updated recommendation of 2007 as provided by ACSM and AHA was created to offer more specific recommendations and to complement the exercise recommendations pr ovided in 1995. Perhaps the greatest benefit provided by the 2007 physical activity update are the clarifications to the 1995 recommendations that it offers. The clear and concise public health message of 1995 is expounded upon within the 2007 update (Haskell, et al., 2007). It should be said that the clarifications within the 2007 physical activity update endow the public with further clear direction regarding exercise frequency, mode and intensit y. A succinct summary of the clarifications to the 1995 recommendation is as fo llows: The 2007 update specifies that individua ls should engage in exercise a minimum of five days each week. Vigorous exercise is included as an op tion for those who opt to exercise at this intensity. A combination of both moderate and vi gorous exercise is suggested as to provide a variety of activities. The recommended amount of exercise (specifically aerobic exercise) is additional to the routine ac tivities of daily living. Physical activity performed in amoun ts larger than the recommendation will yield greater health benefits. 30 minutes of exercise need not be performed continuously, but can be accumulated in shorter bouts for as little as 10 minutes.
5 Muscular strength exercises were added to the recommendation, 8-10 exercises performed on two or more nonconsecutive days each week incorporating all of th e major muscle groups. Lastly, the language within the exer cise recommendation has been altered to conspicuously differentiate betw een aerobic and musc ular strength exercise (Haskell, et al. 2007). As of 2007, the public was provided with specific, practical and applicable exercise recommendations. Both the 1995 and 2007 recommendations serve to increase physical activity levels among a largely sedentary population. Over the course of more than a decade, these publications have elic ited a shift in physical activity guidelines. Despite the collaborative efforts of the various reputab le organizations invol ved (ACSM, CDCP, and AHA) in the composition of the rendered recommendations, physical activity participation levels remain ostensibly low. It is unfortunate that the conferred public health messages have not boosted physical act ivity participation. A lthough past efforts have not yielded significant results, current and future endeavors must continue to improve the health of the nation. It is indisputable that physical activity produces hea lth benefits. Yet, obtaining physical activity is an incessant struggle ev ery American adult seems to encounter. The most common lifestyle is one that is not conducive to physical activity. Technology has reduced the energy required for the activities of daily living and the occupations with the largest salaries are those that are the most sedentary. Thus, the pres ent overweight/obese and sedentary lifestyle epidemic is the unf ortunate outcome. The physical activity and
6 epidemiological data are disheartening and pres ent the health and fitness field with reason to continue conducting research that creates new methods to increase participation in physical activity. The 2007 physical activity recommendations update made mention that two perceptions regarding physical activity are prevalent among Americans. Many individuals believe that physical activity must be vigorous to provide health benefits, and others believe that light ac tivities of daily living are e nough activity to provide health benefits. While both of these pe rceptions are false, they still persist. Past efforts have not been enough to diminish these perceptions nor have they induced increases in physical activity. Novel and inventive me thods relative to physical activity are needed to issue change in this nation. A product by the name of Body Togs, comfortable, wearable weights has recently made its way into the ar ea of exercise science research. These easy to wear weights can be worn during routine activities of daily livi ng, during leisure time physical activity, and also throughout pla nned exercise regimens. Body Togs are wearable resistance, which serve to in crease caloric expenditure without causing increases in perceived exerti on. The ensuing research study in vestigates the effects of Body Togs on various physiological and psyc hological variables dur ing slow and brisk treadmill walking. Objectives The following objectives will be asse ssed in the present research study: 1. Determine the efficacy of Body Togs within a controlled laboratory environment.
7 2. Determine the perceptual responses e licited by incorporati ng Body Togs during slow and brisk walking on a treadmill. 3. Determine changes in perception related to three differentiated RPEs, chest and breathing, legs, and overall, as a result of implementation of the Body Togs. Hypotheses 1. The Body Togs while worn during slow a nd brisk treadmill walking will cause increases in energy expenditure and heart ra te without causing a change in the rate of perceived exertion. 2. Body Togs will be efficient and practical to use during planned slow and brisk treadmill walking. 3. Body Togs will be practical and applicab le to implement w ithin the realm of health and fitness. Limitations 1. Participants within the general and h ealthy population are being used, therefore the results will not be applicable to other populations. 2. The efficacy of the Body Togs product is unknown as the product is new and has not yet been tested.
8 Chapter Two Review of Literature Physical activity is low among Americans and, as a result, energy expenditure has also reached seemingly low levels. Past rese arch has incorporated wearable weights to alter physiological responses and has mild ly assessed perceptual responses during planned aerobic exercise regimens. Exercise science research from the late 1980s to the middle of the 1990s incorporated wearable resistance during walking and running. During this time, a popular trend was to incor porate some type of weights into aerobic exercise. Companies would often market their weights by claiming that caloric expenditure during aerobic exer cise could increase by as much as 300% if their product was implemented. Post-1990s research usi ng wearable weights was abandoned. It is essential to conduct more and current research th at incorporates wearable weights as other variables exist which have not been evaluated. While the proposed study will implement Body Togs during treadmill walking, a review and understanding of past research conducted using wearable/handheld resistance is a necessa ry pre-requisite. A study conducted by Graves et al. (1988) in cluded twelve previously sedentary men between the ages of 18 and 23. The purpose of the study was to examine physiological responses, specifically hemodynamic and en ergy expenditure, as a result of the implementation of hand weights, wrist we ights, and ankle weights. Hemodynamic evaluation was accomplished via three submaximal treadmill tests. Each of the three tests
9 was performed with one of the various types of weights. All tests were performed with a minimum of 48 hours between them and all conditions were randomly assigned. Energy cost of the various types of weights was measured using four separate 8-minute exercise trials. One trial was completed with no weight s, one with hand weights, one with wrist weights, and one with ankle weights. These ex ercise trials were all completed at 60% of heart rate maximum reserve. The results of this study reveal ed that hemodynamic differences only exist if hand weights are use d. The only distinct difference that existed was an increase in diastolic blood pressure and this existed only for the hand weight submaximal exercise test. Relative to energy expenditure, it was found that the implementation of hand weights, wrist weight s and ankle weights yi elds a 14.3% increase in energy expenditure when compared to th e no weight exercise trials. Throughout the various exercise trials rate of perceived exertion (RPE) wa s assessed. An interesting and reputable finding of this study is that while energy expenditu re for all of the weighted conditions was greater than the no weight condition, no change in RPE was found. While the hemodynamic findings of this study are not relevant to the proposed study, the energy expenditure and RPE results are of particular benefit. It is encouraging to the study at hand that no change in RPE existed for any of the weighted exer cise trials. A second study relevant in this review of literature is one that was conducted by Martin (1985). This study examined mechanical and physiologi cal responses when weight was added to the lower extremities during running. The study incorporated fifteen healthy male longdistance runners with an averag e age of 29. Five different load conditions were utilized in this study. The different loaded conditions incl uded: 1) a baseline condition in which no load was added, 2) 0.25 kg added to each th igh, 3) 0.25 kg added to each foot, 4) 0.50 kg
10 added to each thigh, 5) 0.50 kg added to each foot. All conditions were accomplished via running on a treadmill. Changes in oxygen consumption, heart rate and body mechanics were all measured. For all loaded conditi ons, both oxygen consumption and heart rate increased significantly. Relative to mechanical work increases, no changes were found in the mechanics of the shank of the leg or the f oot as a result of added loads. However, the mechanical work of the thigh increased by 9.5% with the heaviest loaded condition when compared to baseline conditions. A secondary finding of this study is that the metabolic cost of running increased by a maximum of 15%. While RPE was not assessed, the increase in energy expenditure as a result of added load is expected and relevant to the Body Togs research. This finding is also consistent with the finding of the previously reviewed study. In a study conducted by Cl aremont and Hall (1988), similar, but not identical variables, when compared to the Martin study were assessed. This study examined the effects of extremity lo ading upon energy expenditure and running mechanics. Five males and three females with an average age of 42 were selected to participate in this study. All pa rticipants had regularly incl uded running in their personal exercise regimens for many years and thus we re experienced with th e selected mode of exercise. The loaded exercise trials were 30 minutes in duration and were performed at each participants self-selected pace. Four different conditions existed: 1) a no-load, control run, 2) carrying ba rbell hand-weights weighing 0.45 kg for women and 0.90 kg for men, 3) 0.45 kg weights strapped to each ankle, 4) carrying both hand and ankle weights totaling 0.98 kg for women and 2.7 kg for men. Relative to the kinematic findings of this study, results were consiste nt with the study conduc ted by Martin. Little to no changes were found in the body mechanic s involved in running de spite added loads.
11 Energy expenditure increased by a maximum of 8% as a result of the highest loaded condition. The results described he re are relevant to the presen t research study in that the loaded conditions implemented are similar to the conditions that will be used with Body Togs. It is also a positive finding that added loads do not compromise body mechanics and likely prove that the Body Togs will be sa fe and effective. However, this study fails to incorporate RPE relative to all of the various loaded tria ls. Another study of relevance within this review of the literature is a study that was conducted by Rodgers, Vanheest, and Schachter (1995). This study evaluate d energy expenditure during submaximal walking with Exerstriders. Ex erstriding is a form of walk ing that is modified by the incorporation of specially designed walking st icks (Exerstriders). It is important to mention that each Exerstrider weighed approximately 13-14 ounces, a total of an additional two pounds. Ten moderately active females participated in this study. All participants received traini ng in Exerstrider use prior to the study. Each participant completed two randomly assigned trials. Bo th trials completed were two, 30 minute treadmill walking trials one of which included the Exerstriders while the other trial did not. Throughout each exercise trial, expired air was collected for two minute periods in Douglas bags using open circuit spirometr y. VO2 and RER were calculated to account for overall caloric expenditure during both exer cise trials. RPE was also obtained every two minutes using the original Borg 6-20 s cale. Exercise trials were separated by a minimum of 48 hours and were conducted at th e same time of day. Results yielded that the average heart rate during walking with the Exerstride rs was 132 bpm while walking without the Exerstriders yi elded an average heart rate of 121 bpm. There was no significant difference in RPE relative to the two exercise conditions. The results of this
12 study are similar to the findings discussed in all of the previously reviewed studies. Energy expenditure increased (an average of 5.8 kilocalories per minute) as a result of the Exerstriders while RPE remained unchanged. This study is significan tly relative to the Body Togs research in that it incorporated a nove l device rather than just implementing traditional hand or ankle weights. It also re veals that once again, caloric expenditure can increase without any change occurring in RPE. Increases in energy e xpenditure absent of changes in RPE allow the time spent in exercise to be of greater benefit. A final study to be reviewed examined the metabolic and he modynamic responses to walking with hand weights in older individuals (E vans, et al., 1994). The particip ants in this study were 19 physically active males and females between the ages of 60 and 70. All were free of cardiovascular diseases and we re not taking medication that would interfere with heart rate and blood pressure during exercise. All participants were allowed to practice walking on the treadmill prior to participation in the study. Additionally, two separate speeds were assigned to each participant. E ach participant was given the opportunity to select a speed and a second speed was assigned via 70% of heart rate reserve as determined by the Karvonen formula. Participants performed each exercise trial for ten minutes at the selfselected speed and for ten minutes at the 70% of heart rate reserve speed. Each exercise trial was randomly assigned using four va rious conditions: 1) no weight ,2) 0.45 kg hand weights, 3) 1.36 kg hand weights, 4) 2.27 kg ha nd weights. Expired gases were collected every 60 seconds and were used to dete rmine oxygen uptake, ventilation and the respiratory exchange ratio. RPE was also as sessed during the last ten seconds of each minute of exercise. Blood pressure was m easure via traditional auscultation using a sphygmomanometer and was taken at rest and every two minutes during exercise trials.
13 The results of the study yiel ded no difference between self-selected speed and 70% of heart rate reserve speed for heart rate, oxyge n consumption, ventilation, systolic blood pressure, and diastolic blood pressure. Therefor e, it was concluded that any changes were as a result of the addition of the hand weights. Heart rate increased significantly across all four exercise conditions. Both systolic and diastolic blood pressure increased for all of the weighted conditions when compared to the no weight trial. Additionally, hand weights had to be 1.36 kg or greater in orde r to create increases in VO2. Also, metabolic increases as great as 18.9% occu rred as a result of the hand weights. Changes in RPE did occur as a result of the added hand weights. However, the highest RPE was 12 and this was found only during the 2.27 kg hand weight tria l. Thus, it can be concluded that while RPE did change, the work being performed by the participants was perceived to be light. The researchers in this study concluded that the addition of hand held weights does not alter RPE. Finally, this study confirmed the va rious findings of the previously reviewed studies. It is significant that an older population was used for this study, as this is something to consider using in future research endeavors. All in all, the various findings not only support the hypothese s of the Body Togs Research study, but support the need for the assessment of the other variables that have yet to be addresse d in past research.
14 Chapter Three Methodology Participants Twenty five men and women aged 18-45 years were recruited (mean age = 24.2 5.92 years, mean height = 66.9 3.50 inches, mean BMI = 25.0 4.12). Each participant provided informed consent and co mpleted a health status questionnaire, to determine risk stratification, and completed a physical exam administered by a sports medicine physician in accordan ce to standard guidelines. Lab Trials Each participant was required to visit th e Health and Exercise Science Laboratory eleven times. A brief description of each labo ratory visit is provide d in the table below. Each laboratory visit required approximatel y one hour and each trial was separated by a minimum of 24 hours.
15 Table One Description of Laboratory Visits Visit Description 1 Screening to include a physical ex am, informed consent, and resting assessments 2 Maximal treadmill test 3 Workload establishment and familiarization with treadmill and togs 4-11 Experimental exercise trials Screening (Visit 1) Each participant was screened for partic ipation based on established criteria. The screening included a comprehensive health hi story, pre-participati on in a physical exam administered by a physician, completion of the informed consent document, assessment of resting heart rate and blood pressure, a nd assessment of body composition by way of skinfold calipers. Maximal Exercise Testing (Visit 2) Each participant completed a maximal treadmill test that included measurements of heart rate, blood pressure, perceived exertion, and metabolic gas exchange. The protocol that was utilized was a ramp-style te st that began with a slow walk and increased in speed each minute by 0.5 miles pe r hour until volitional exhaustion.
16 Workload Establishment and Familiarization (Visit 3) Each participant was asked to walk on the treadmill to determine the exercise intensity for subsequent exercise trials. One workload corresponded to a slow walk which was designed to replicate walking that is associated with activities of daily living. The second workload corresponded to a vigorou s walk which was designed to replicate walking that is purposeful and associated with fitness. Workload establishment of the two separate speeds took place over a 30 minute time period with 15 minutes designated to each walking speed. Collectively, the two wo rkloads were self-selected and were intended to reflect public health recommendati ons related to lifest yle physical activity. Familiarization with the togs included instru ction on proper size, lo cation, and fit for the leg and wrist. The purpose of th is portion of the trial was to provide exposure to the togs prior to the experimental manipulation to lim it the perceptual impact of wearing a novel device. Workload establishment and familiarization was determined via the following script and was delivered by the research team. Prior to slow walking speed selection: It is important for you to remember that the walking speed you select should be the equivalent of a slow walk. It is also essential for you to keep in mind that you will have to maintain this speed for a duration of 30 minutes during all exercise trials. We ask that you refrain from using the handles located on either side of the treadmill. These are for emergency use only.
17 At 7 minutes 30 seconds: Do you still believe that this is a slow walk? If part icipant desired to reduce or increase the previously selected speed they did so at this time. Otherwise this was the slow walk speed that was be maintain ed throughout the en tire research study. Prior to brisk walking speed selection: It is important for you to remember that the walking speed you select should be the equivalent of a brisk wal k. It is also essential for you to keep in mind that you will have to maintain this speed for a duration of 30 minutes. We ask that you refrain from using the handles located on either side of the treadmill. These are for emergency use only. At 7 minutes 30 seconds: Do you still believe that this is a brisk wa lk? If participant desired to reduce or increase the previously selected speed they did so at this time. Otherwise this was the brisk walk speed that was maintained throughout the entire research study. Experimental Exercise Trials (Visits 4-11) The eight experimental trials allowed for both exercise conditions /intensities to be tested across four equipment conditions/combi nations. The two exerci se conditions were the slow walk and brisk walk which were expected to produce metabolic responses in the 20-40% and 40-60% of maximal oxygen consumption, respectively. The four equipment combinations included: no togs, le g and arm togs, arm togs only, and leg togs
18 only. Each experimental exercise trial lasted for 30 minutes in an effort to replicate the duration recommended by current physical activity guidelines. Heart rate was measured continuously. Oxygen consumption was measur ed from minute 24 to minute 29. Exertion was assessed every six minutes during the tria l. It should be noted that from minute 24 through minute 29, exertion was not assessed. At 29 minutes and 45 seconds the last measure of exertion was reported. Exertion wa s assessed again after the completion of exercise. All trials were orga nized into balanced sequences for participants relative to speed and tog conditions. Table 2 Exercise Trial Conditions Togs None Arm & Leg Leg Only Arm Only Intensity Slow Walk Brisk Walk Protocol Description Prior to each exercise trial, the meta bolic cart was properly calibrated. A polar heart rate monitor was supplie d to each particip ant upon arrival to the laboratory. Brief instruction was provided on where to place th e heart rate monitor and how to wear it correctly. A warm-up of 30 sec onds preceded every exercise tr ial. At the conclusion of the warm-up the treadmill was adjusted to either the slow or brisk walking speed as previously determined. Every 6 minutes ra te of perceived exertion was assessed. At minute 24 of the exercise trial the air cu shion mask was placed on the participant.
19 Expired metabolic gases were collected fr om minute 24 to minute 29. At minute 29, the air cushion mask was removed. At 29 minutes and 45 seconds a final rate of perceived exertion was recorded. At 30 minutes the exer cise trial concluded and a 30 second cooldown with an intensity equal to th at of the warmup transpired. Instrumentation Variables of interest during exercise included: heart rate, perceived exertion, and oxygen consumption. Heart rate (HR) was measured using a Polar heart rate monitor (Polar, USA). Rating of perc eived exertion (RPE) was measured with Borgs CR-10 scales (Borg, 1998). This scale allows fo r the differential assessment of exertion reflecting overall, legs, and chest. Assessm ent of exertion in this manner allowed for inspection of how the various tog conditions differentially impacted various aspects of effort sense. Oxygen consumption was measur ed by way of open circuit spirometry. Research Design and Data Analysis The research design utilized a 2 (int ensity: slow walk and brisk walk) x 4 (equipment: no togs, arm and leg, leg only, ar m only) repeated measures ANOVA. Each participant served as their ow n control. The table below depi cts the basic design features. Main and interaction effects were follo wed by dependent t-tests. Criterion for significance for all tests was set at p < 0.05. The sample size was based on basic power calculations and related literature. While a sm aller sample size may have been plausible for physiological variables where larger effect s can be expected, perceptual variables tend
20 be have smaller effect sizes and require a larger sample si ze. Exact p-values are reported that the reader may use discretion and take heed to possible Type 1 error. Inclusion/Exclusion Criteria All participants were low risk according to ACSMs Guidelines for Exercise Testing and Prescription which requires ab sence of cardiovascular, metabolic, and pulmonary disease or related symptoms (A CSM, 2006). Participants age ranged from 18 to 45 years. Physical activity /fitness status and body mass index was not utilized as inclusion/exclusion criteria. Th e design instead allowed any range of activity and weight status.
21 Chapter Four Results Graded Exercise Testing All participants completed a graded maximal exercise test on a treadmill. A maximal effort is indicated by 90% of age pr edicted maximal heart rate, an RER of 1.15 or greater and an RPE of 19 ( on the 6-20 scale). All must be achieved for the exercise test to qualify as a maximal effort. The mean data indicate that the conducted maximal exercise tests were a maxima l effort (VO2 = 42.7 mL x kg-1 x min -1 6.62). Maximal heart rate (186 11.7 beats x min -1) met the cr iterion for a maximal effort based on age (90% of age predicted maximal heart rate). Peak respiratory exchange ratio (RER = 1.19 0.09) was above the criterion of 1.15 for a ma ximal effort. Peak RPE (18.6 0 .79) was equal to the criterion of 19 (6-20 scale) for maximal effort. Collectively, it can be inferred as illustrated by the heart rate, RER, and RPE that a maximal effort was obtained. Self-Selected Speed The average self-selected slow sp eed was 2.6 0.36 mph. The minimum slow speed selected was 2.0 mph and the maximu m slow speed selected was 3.2 mph. The average self-selected brisk speed was 3.5 0.30 mph. The minimum brisk speed selected was 2.9 mph and the maximum brisk speed select ed was 4.0 mph. T-tests indicate that the two self-selected speeds were signifi cantly different (p < 0.00; ES = 2.56).
22 Rate of Perceived Exertion Within the study design, rate of percei ved exertion (RPE) was assessed via the Borg 6-20 scale. However, the present study implemented RPE as a differentiated measure. RPE was assessed separately for th e chest and breathing, the legs, and overall. The purpose of the differentiated RPE was to de termine a variety of different perceptual responses related to different regions of the body. The Body Togs are worn on the arms and the legs and specific per ceptions of exertion as opposed to simply general exertion were pertinent to the research study. RPE Overall For the variable of RPE overall, resu lts indicate that there was a significant main effect for speed (p < 0.001). A significant ma in effect also existed for differences in Body Tog conditions for RPE overall (p = 0.014) (see Figure 1). A significant interaction effect was not found (p = 0.174). The data indicate that participants experienced higher levels of ove rall exertion at the brisk speeds than at the slow speeds. Furthermore, participants also experienced higher levels of overall exertion when wearing the Body Togs. Follow-up dependent t-tests yielded signi ficant p-values for comparison of trials at a brisk speed with no t ogs compared to trials at a brisk speed with leg togs (p = 0.018; ES = 0.62) and for trials at a slow speed with both togs compared to trials at a slow speed with arm togs (p = 0.029; ES = 0.40) (see Table 3 and Figure 1).
23 Table 3 Rate of Perceived Exertion Overall Figure 1. RPE Overall 7 8 9 10 11 12 13 NoneArmsLegsBothRPETogs Slow Brisk Variable 1 Mean/SD1 Variable 2 Mean/SD2 P-value Effect size Brisk None 9.65 1.97 Brisk Both 10.59 2.87 .108 .39 Brisk None 9.65 1.97 Brisk Arms 10.29 1.93 .135 .33 Brisk None 9.65 1.97 Brisk Legs 10.95 2.28 .002 .62 Brisk Both 10.59 2.87 Brisk Arms 10.29 1.93 .463 .13 Brisk Both 10.59 2.87 Brisk Legs 10.94 2.28 .303 .14 Brisk Arms 10.29 1.93 Brisk Legs 10.94 2.28 .127 .31 Slow None 8.59 1.77 Slow Both 8.94 1.75 .370 .20 Slow None 8.59 1.77 Slow Arms 8.29 1.49 .206 .18 Slow None 8.59 1.77 Slow Legs 8.82 1.63 .410 .14 Slow Both 8.94 1.75 Slow Arms 8.29 1.49 .029 .40 Slow Both 8.94 1.49 Slow Legs 8.82 1.75 .768 .07 Slow Arms 8.29 1.49 Slow Legs 8.82 1.63 .108 .34
24 RPE Chest and Breathing The variable of RPE ches t and breathing revealed a significant main effect for speed (p < 0 .001) but not for Body Togs conditions (p = 0.058) (see Figure 2). Additionally, no interaction e ffect was found for RPE ches t and breathing (p = 0.657). Thus, participants experienced higher levels of exertion in the ches t and breathing during the brisk speed exercise trials as compared to the slow speed exercise trials. While higher levels of exertion were experienced in the ch est and breathing due to an increase in speed, the addition of the togs did not produce higher levels of ex ertion in this region. Follow-up dependent t-tests were conducte d and were significant for exer cise trials conducted at a brisk speed with no togs compared to trials at a brisk speed with leg togs (p = 0.018; ES = .018) and for exercise trials conducted at a slow speed with leg and arm togs compared to trials conducted at a slow speed with ar m togs (p = 0.034; ES = .034) (see Table 4 and Figure 2). Table 4 Rate of Perceived Exertion Chest and Breathing Variable 1 Mean/SD1 Variable 2 Mean/SD2 P-value Effect Size Brisk None 9.59 1.84 Brisk Both 10.12 2.55 .326 .24 Brisk None 9.59 1.84 Brisk Arms 9.59 2.06 1.000 .00 Brisk None 9.59 1.84 Brisk Legs 10.29 1.93 .018 .37 Brisk Both 10.12 2.55 Brisk Arms 9.59 2.06 .236 .23 Brisk Both 10.12 2.55 Brisk Legs 10.29 1.93 .661 .08 Brisk Arms 9.59 2.06 Brisk Legs 10.29 1.93 .111 .35 Slow None 8.47 1.62 Slow Both 8.65 1.54 .565 .11 Slow None 8.47 1.62 Slow Arms 8.12 1.65 .111 .21 Slow None 8.47 1.62 Slow Legs 8.53 1.55 .805 .04 Slow Both 8.65 1.54 Slow Arms 8.12 1.65 .034 .33 Slow Both 8.65 1.54 Slow Legs 8.53 1.55 .707 .08 Slow Arms 8.12 1.65 Slow Legs 8.53 1.55 .130 .26
25 Figure 2 RPE Chest and Breathing RPE Legs The variable of RPE legs also revealed a significant main effect for speed (p = 0.002) and for Body Togs conditions (p < 0.001) (see Figure 3). However, no interaction effect was found for RPE legs (p = 0.375). At the brisk speeds the exertion of the legs was greater than that of the slow speeds. When the Body Togs were worn the exertion of the legs was also greater. Dependen t t-tests were conducted and proved to be significant for exercise trials conducted at a brisk speed with no togs compared to trials conducted at a brisk speed with leg togs (p = 0.002; ES = .37) brisk speed with arm togs compared to the brisk speed with leg togs (p = 0.007; ES = .35), slow speed with no togs compared to the slow speed with arm togs (p = 0.023; ES = .21), slow speed with leg and arm togs compared to the slow speed with arm togs (p = 0.004; ES = .33 ), and slow 7 8 9 10 11 12 13 NoneArmsLegsBothRPETogs Slow Brisk
26 speed with arm togs compared to the slow sp eed with leg togs (p = 0.002; ES = .26) (see Table 5 and Figure 3). Table 5 Rate of Per ceived Exertion Legs Variable 1 Mean/SD1 Variable 2 Mean/SD2 P-value Effect Size Brisk None 10.18 2.10 Brisk Both 11.00 3.16 .140 .31 Brisk None 10.18 2.10 Brisk Arms 10.35 2.18 .627 .08 Brisk None 10.18 2.10 Brisk Legs 11.59 2.58 .002 .30 Brisk Both 11.00 3.16 Brisk Arms 10.35 2.18 .094 .24 Brisk Both 11.00 3.16 Brisk Legs 11.59 2.58 .172 .21 Brisk Arms 10.35 2.18 Brisk Legs 11.59 2.58 .007 .52 Slow None 9.00 1.94 Slow Both 9.47 2.03 .270 .24 Slow None 9.00 1.94 Slow Arms 8.29 1.49 .023 .41 Slow None 9.00 1.94 Slow Legs 9.65 1.80 .085 .35 Slow Both 9.47 2.03 Slow Arms 8.29 1.49 .004 .67 Slow Both 9.47 2.03 Slow Legs 9.65 1.80 .693 .09 Slow Arms 8.29 1.49 Slow Legs 9.65 1.80 .002 .83 Figure 3 RPE Legs 7 8 9 10 11 12 13 NoneArmsLegsBothRPETogs Slow Brisk
27 Chapter Five Discussion The present study was designed to examine three differentiated rates of perceived exertion (RPE) at two different self-selected speeds (slow and brisk) under four various Body Togs conditions. A total of eight different experiment al trials were completed by all participants. RPE for th e chest and breathing, the legs and overall was measured every six minutes during all exercise trials. Th e findings of this research study reveal that overall exertion and leg exertion increased among participants as a re sult of increases in speed and as a result of adding the Body T ogs. RPE of the chest and breathing also increased as a result of speed increases, but was found to be unchanged by the addition of Body Togs. It is plausible th at perceptual responses of the chest would be unchanged by the Body Togs as this is not an anatomi cal region where the togs are worn and thus exertion would not increase for this variable during the exercise trials. The Body Togs are worn on the forearms and the lower leg. It is feasible that RPE overall and RPE legs would increase due to the added weight of th e togs. With the additi on of the togs to the legs, an increase in exertion in this region seems possible. Overall exertion would also increase simply because weight was a dded to the body. However, RPE chest and breathing was likely unchanged because the togs were not added to this region of the body and because the mode of exercise was walking.
28 The assessment of RPE overall indicated that trials performe d at a brisk speed with no togs as compared to trials performe d at a brisk speed with leg togs had higher exertion responses. Also, when exercise trials performed at a slow speed with both leg and arm togs were compared to exercise trials performed at a slow speed with arm togs a difference in perceived effort also existed. It is unexpected that exertion would increase during both the slow and brisk walking for th e above trial comparisons and not also for others. Walking with added weight adds effo rt to the endeavor, still, it cannot be explained why RPE overall increases were significant for trial comparison of no togs and leg togs at the brisk speed, in addition t o, arms only and leg and arm togs at the slow speed, but were not significan t for other trial comparisons. It seems more likely that a pronounced and significant differe nce would have existed for trial comparisons with no togs and leg and arm togs for both the slow a nd brisk speed. Yet, the data did not present this finding. RPE chest provided two trial comp arisons which presented meaningful differences. Exercise trials ex ecuted at a brisk speed with no togs compared to exercise trials executed at a brisk speed with leg togs were significantly different when RPE of the chest was considered. While this outcome can be explained by the added weight of the togs, it is surprising that the same outcome did not exist for exercise trials completed at a brisk speed with no togs compared to trials completed at a brisk speed with both leg and arm togs. Another significant finding re lated to RPE chest was found for the comparison of exercise trials accomplished at a slow speed with arm togs and exercise trials completed at a slow speed with both ar m and leg togs. It is slightly difficult to fathom why a difference existed for trials at a slow speed with arm togs compared to
29 trials at a slow speed with both arm and leg togs, yet did not exist for trials at a slow speed with no togs compared to trials at a slow speed with both arm and leg togs. Again, as was present with RPE overall, differences were found for some trial comparisons but not for all trial comparison in which differences would be expected. Finally, RPE legs revealed more differe nces in RPE than did the other two RPE variables. Exercise trials completed at a br isk speed with no togs compared to exercise trials completed at a brisk speed with le g togs were signifi cantly different when considering RPE legs. Also exercise tria ls performed at a brisk speed revealed a significant difference for those with arms togs when compared to those with leg togs. Once again, it seemed likely that a differen ce would exist between exercise trials performed at a brisk speed with no togs when compared to trials performed at a brisk speed with both arm and leg togs, yet this did not transpire. RPE legs for exercise trials at a slow speed revealed differences for co mparison of no togs compared to arm togs only, arm togs only compared to leg togs onl y, and arm togs only compared to both leg and arm togs. The hypotheses of the present study include d that RPE would not be altered, but the findings reveal that RPE did increase. Colle ctively, it was expected that if differences in RPE were found, trial comparisons for the various RPEs would reveal a pattern in which changes in RPE occurred. It seemed lik ely that for both speeds, increases in RPE would be found for all trials that were perfor med with no togs when compared to trials that were conducted with both leg and arm togs It also seemed less likely that increases in RPE would be found for trials performed with no togs when compared to trials performed with only arm togs. While a sequ ential increase in RPE is what seemed
30 probably if changes were to o ccur, the data did not indicate a sequence that explains how or as to why some trial comparisons were significant and others were not. In reviewing similar resear ch studies of the past in which wearable weights were added to exercise and RPE was assessed, the re sults of the present study prove to be quite unique. Graves (1988) examined the impact of handheld weights weighing approximately two pounds during treadmill running. RPE was m easured and was found to be unchanged by the added weight. Rodgers, Vanheest and Sc hachter (1995) evalua ted the impact of Exerstriders, walking sticks which equate to an added two pounds. These were added to treadmill walking and RPE was assessed every two minutes during exercise trials. The results of this study also found that while implementing the Exerstriders added body weight and increased heart rate, RPE remain ed unchanged. A final study similar to the present study was conducted by Evans (1994). This study included a unique population in that the participants were older individuals Treadmill walking was the selected mode of exercise and various amounts of weight were added to the exercise. RPE was measured and was found to be unchanged except during th e trials in which the highest amount of weight (2.27 kg) was added. The present study is similar to the previ ous studies in that weight was added to exerci se and RPE was measured. However, the Body Togs research study is unique in that three di fferentiated RPEs were measured during the exercise. The findings of the study present rela tively inconsistent results as compared to the previously reviewed studies. The preceding st udies were fairly consistent in that they found RPE to be unchanged despite the weight added to the exercise. The present study found that RPE was changed first due to differe nces in speed and also due to differences in Body Togs conditions. It is imperative to mention that the leg togs and arm togs
31 together add approximately 7.5 pounds (3.4 kg) of extra weight. Past studies added no more than 5 pounds of weight and thus th e extra 2 pounds included in this study likely accounts for some of the changes in RPE. It is pertinent to mention that while Body Togs come in an assortment of sizes, all arm togs are equal in weight as are all leg togs. The strengths of the resear ch study include that all part icipants were low risk as defined by ACSMs risk stratification qualificat ions. All exercise tria ls were conducted in the same environment and the research team made every effort to keep trial protocol consistent. Additionally, RPE is most co mmonly reported as an overall measure of exertion. To assess how the Body Togs impacted other areas of the body as it relates to exertion, three differentiated measures of RP E were included. The limitations of the study include that this is the ve ry first research study of its kind in that Body Togs are a novel device and prior to this study had not b een included in any scientific research. The variable of measure in the study was RP E and perceptual responses are often unpredictable and highly individualized. This al one is merit for a repeat research study, as well as, future research which includes Body Togs. Future research with Body Togs shoul d include perceptual responses during brisk treadmill walking compared with tread mill running. The differences in perception of exertion would likely be more pronounced and may present a more consistent relationship than was found in the presen t study. Other Body Togs research studies could also include wearing the togs during activities of daily living (ADLs) and measuring perceptual responses as they relate to adding the togs to ADLs. Practical application of adding Body Togs to exer cise include that adding weight to the body, whether it be during exer cise or during ADLs, increases caloric
32 expenditure. If an individual weighs more, w ithout question, that i ndividual burns more calories performing ADLs and during exerci se. As discussed in the introduction, the obesity epidemic is a great feat that the health and fitness professional is avidly trying to combat. New and innovative products such as Body Togs are appropriate to include in exercise regimens, as well as, daily living in order to induce small, meaningful changes. Conclusions of the study in clude that more research is necessary in order to thoroughly assess the perceptu al responses Body Togs pr oduce during exercise. The togs are a new device and more research is necessary because they are an up and coming product. More research is also necessary to c onfirm or refute the inconsistent perceptual response relationship that was found in the pr esent study. A more consistent relationship between adding Body Togs to exercise and exertion perceptions could exist but will never be discovered without future research.
33 List of References American College of Sports Medicine. ACSMs Guidelines for Exercise Testing and Prescription (6th ed.). Philadelphia, PA: Lippincott, Williams & Wilkins, 2006. Borg, G. Borgs Perceived Exertion and Pain Scales Champaign, IL: Human Kinetics, 1998. Claremont, A. & Hall, S. (1988) Effects of extremity loading upon energy expenditure and running mechanics. Medicine and Science in Sports and Exercise, 20, 167-171. Evans, B., Potteiger, J, Bray, M., & Tutte J. (1994) Metabolic and hemodynamic responses to walking with ha nd weights in older individuals. Medicine and Science in Sports and Exercise, 26, 1047-1052. Graves, J., Martin, D., Miltenberger, L., & Poll ock, M. (1988) Physiolo gical responses to walking with hand weights, wris t weights, and ankle weights. Medicine and Science in Sports and Exercise, 20, 265-271. Haskell, W., Lee, I., Pate, R., Powell, K., Blai r, S., Franklin, B., et al. (2007) Physical activity and public health: updated recomm endation for adults from the American college of sports medicine a nd the American heart association. Medicine and Science in Sports and Exercise, 39, 1423-1434. Martin, P. (1985). Mechanical and physiologi cal responses to lower extremity loading during running. Medicine and Science in Sport and Exercise, 17, 427-433. Pollock, M., Gaesser, G., Butcher, J., Despres, J., Dishman, R., Frank lin, B., et al. (1998) The Recommended quantity and qualit y of exercise for developing and Maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults. Medicine and Science in Sports and Exercise, 30, 975-991. Rodgers, C., Vanheest, J., & Schachter, C. (1995) Energy expenditure during submaximal walking with Exerstriders. Medicine and Science in Sports and Exercise, 27, 607-611.
34 Russell, P., Pratt, M., Blair, S., Haskell, W., Macera, C., Bouchard, C., et al. (1995) Physical activity and pub lic health: a recommendation from the centers for disease control and preven tion and the American college of sports medicine. American Medical Association, 273, 402-407.