The purpose of this study was to investigate work performance on a semi-defined, low calorie diet during daily periods of light and moderately heavy activity. Four male graduate students volunteered for the ten week study which was divided into five experimental periods. During Period 1 (control) the subjects received a balanced, normal diet of usual foods providing approximately 3600 calories per day and meeting the Canadian Dietary Standards for all nutrients. During this two week period, a "normal" level of activity was maintained. Period 2 consisted of ten days on a semi-defined low calorie diet with continued "normal" activity. The low calorie diet provided, approximately 1800 calories daily, plus one multiple vitamin pill. It met the Canadian Dietary Standards for all nutrients. Period 3 was a repeat of Period 1, two weeks during which the subjects received approximately 4000 calories, per day, of the control diet. Again, "normal" activity was maintained. Period 4 consisted of ten days of the same low calorie semi-defined diet as Period 2, with an additional daily energy expenditure, per subject, of approximately 500 calories. Period 5 was the same as Periods 1 and 3, two weeks of the control diet with "normal" activity. Several physiological variables were measured during the last two days of each experimental period to ascertain the effects of the treatment conditions on the cardiorespiratory and general fitness of the subjects. Strength measurements and maximal oxygen uptake determinations remained unchanged for the duration of the study, whereas, physical work capacity (PWC 170) decreased continually, beginning in the third experimental period. Total body weight decreased during Periods 2 and 4. Period 4, which involved increased physical activity caused slightly more weight loss than Period 2. Anthropometric measurements, body composition, and body density were only slightly changed, the changes paralleling the changes in body weight. Pasting blood samples were taken twice during each experimental period; midway through the period and on the last day. Twenty-four hour urine samples were also collected on the final day of each study period. Although some minor changes did occur, most biochemical parameters remained within normal limits. The blood glucose concentrations decreased during Periods 2 and 4 and plasma free fatty acid levels increased. Plasma cholesterol levels decreased during Periods 2 and 4, as did the hematocrit, hemoglobin, total serum protein, serum albumin, and blood urea nitrogen concentrations. Plasma Vitamins A and E, as well as the serum Vitamin C levels also decreased during Periods 2 and 4. Urinary thiamine excretion increased, possibly in response to the greater percentage of calories derived from endogenous fat stores Generally speaking, the low calorie diet situations were well tolerated by the subjects. Physiological measurements indicated a change only in physical work capacity, which decreased during the study. Biochemical determinations revealed definite alterations; however, most parameters remained within the normal limits. / Land and Food Systems, Faculty of / Graduate

Introduction: Dyspnea on exertion (DOE) is a common symptom experienced by 40% of healthy obese women. Dyspnea has at least two dimensions: a sensory (intensity) and an affective dimension. The affective dimension was measured in this study by unpleasantness and negative emotions (i.e., depression, anxiety, frustration, anger, and fear) related to DOE, measured as rating of perceived breathlessness (RPB). Purpose: To examine whether RPB during exercise was associated with unpleasantness and negative emotions and the relative exercise intensity and to examine whether 12-week exercise training can reduce unpleasantness and negative emotions related to breathlessness in healthy obese women. Methods: A secondary analysis was conducted from data collected from an interventional study. Volunteers underwent body measurements, underwater weighing, pulmonary function testing, and a constant-load cycle test (60 watts). RPB, unpleasantness, and negative emotions related to DOE were obtained. Results: There was a positive relationship (n = 74) between RPB and unpleasantness (r = .61) and RPB and anxiety (r = .50). There was a relationship (n = 52) between unpleasantness and %VO₂max, r = .28 as well as %HRmax r = .38; anxiety and %HRmax, r = .28 (p < .05). Unpleasantness and anxiety were different between groups (n=55). Unpleasantness was higher in the +DOE group (M = 3.91, SD = 2.29) than the–DOE group (M = 1.37, SD = 2.01), t(53) = 4.27, p = < .0001; Anxiety was higher in the +DOE group (M = 2.76, SD = 2.99) than in–DOE group (M = 0.72, SD = 1.23), t(41.95) = 3.45, p = < .001. Within group analysis (n = 13) showed that participants in +DOE experienced a decrease in unpleasantness after 12-week exercise training (p = .013; paired t test). There was a main effect of exercise on unpleasantness (p = .0307) and a group x training interaction (p = .0285) indicating that persons with DOE prior to the exercise intervention experienced less unpleasantness after the intervention. Conclusion: Unpleasantness and anxiety have been identified as the most common symptoms associated with RPB. Healthy obese women who engage in physical activity may experience higher rates of unpleasantness and anxiety based on their relative intensity of exercise. In addition, women with DOE who experience unpleasantness as an associated symptom could possibly decrease the level of unpleasantness if they engage in an exercise-training program.

Sildenafil increases oxygen delivery and maximal exercise capacity at very high altitudes (greater than or equal to 4300 m) and has been shown to improve short-duration exercise performance in some individuals at simulated high altitude (3900 m). It is unknown whether sildenafil improves maximal exercise capacity and longer duration exercise performance at moderate and high altitudes where competitions are more common. Additionally, the effects of sildenafil on women exercising at altitude have not been examined. The purpose of this study was to determine the effects of sildenafil on cardiovascular hemodynamics, arterial oxygen saturation (SaO2), peak exercise capacity (Wpeak), and 15-km time trial performance, in endurance-trained men and women at simulated moderate (MA; 2100 m, 16.2 % FIO2) and high (HA; 3900 m, 12.8% FIO2) altitudes. Eleven male and 10 female subjects completed two HA Wpeak trials following the ingestion of placebo or 50 mg sildenafil in randomized, counterbalanced, and double blind fashion. Subjects then completed four exercise trials (30 min at 55% of Wpeak + 15-km time trial) at MA and HA following the ingestion of placebo or 50 mg sildenafil in randomized, counterbalanced, and double blind fashion. Sildenafil had little influence on cardiovascular hemodynamics for either gender at MA or HA, but did result in higher SaO2 values compared to placebo during steady state and time trial exercise in men at HA only. Sildenafil did not affect Wpeak or 15-km time trial performance in either gender at MA or HA. We conclude that sildenafil is unlikely to exert beneficial effects at altitudes < 4000 m for a majority of the population.

Planning a multi-day bicycle tour is a time intensive and difficult task. To enable cyclists to construct their own multi-day tour routes, we propose an automated system which, given an origin, destination, and points of interest, generates detailed bicycle tour routes of minimal perceived exertion. This dissertation is comprised of three bodies of work contained in chapters 2, 3, and 4, respectively. In the first work, chapter 2, we build and test a model of the perceived exertion of different categories of cyclists on a daily path within a long bicycle tour. We first propose an additive formula for calculating the perceived exertion of cyclists on component parts of a tour and then present the results of a survey designed to verify the accuracy of the model. In the second work, chapter 3, we describe an algorithmic procedure for transforming a traditional road graph into a topographical graph. To that end we use polyline data from the OpenStreetMap (OSM), elevation data from the U.S. Geological Survey, and a model of perceived exertion for bicyclists of different levels of expertise. Our topographical graph allows for the calculation of the perceived exertion over any sequence of road segments (a path) for bicyclists of different levels of expertise and serves as input for generating paths of minimal perceived exertion. In the final work, chapter 4, we describe a procedure for constructing bicycle routes of minimal perceived exertion for cyclists of different levels of expertise over a multi-day tour. Given a cyclists origin, destination, selected points of interest, and a level of cycling expertise, this procedure generates a multi-day bicycle tour as a collection of successive daily paths that begin and end at overnight accommodations. We demonstrate the implementation of this procedure on an example multi-day tour route in California and present the results of a survey designed to evaluate the daily paths constructed. In summation, this dissertation contributes a new metric of perceived exertion for bicycle riders, a new topographical graph, and a procedure for constructing multi-day bicycle tour routes of minimal perceived exertion for bicyclists of different levels of expertise.

Thesis (M.S.)--University of Wisconsin--Madison, 1985. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 81-86).

Oral creatine supplementation has been shown to increase skeletal muscle total creatine (TCr) content, and in some cases improve performance in high-intensity short duration exercise. A variety of factors related to an enhanced efficacy of adenine nucleotide metabolism have been demonstrated as partly responsible for this ergogenic effect. Also, there is evidence that high-intensity sprint training results in a decrease in muscle total adenine nucleotide (TAN) and/or ATP stores. This placebo controlled double-blind study examined whether an oral creatine supplementation regimen would 1) increase muscle TCr content, 2) attenuate any loss in TAN or ATP during intermittent sprint training, and 3) have an ergogenic effect on performance after sprint training. Thirteen male endurance trained cyclists ingested 20 g of creatine monohydrate supplement or placebo per day for 7 days, after which they ingested a maintenance dose of 2 g creatine or placebo per day for the remainder of the trial (15d). While on the maintenance dose, subjects performed intermittent sprint training (ST) on a cycle ergometer (10 x 10 s sprints with 140 s active recovery) for 6 consecutive days and a 7th day after one day of rest. Performance tests were performed before and after ST, and metabolic tests were performed on the 1st and 7th day of ST. TCr increased significantly with creatine supplementation (creatine group pre: 121 ± 4, post: 147 ± 9; vs. placebo group pre: 122 ± 4, post: 125 ± 4 mmol/kg dm; mean± SEM; p<0.05). The increase in TCr correlated with the percentage Type IIB fibres (r=0.95, p<0.005). By day 7 of ST, TCr content was no longer significantly higher than pre-supplementation levels despite the maintenance dose of creatine. ST resulted in a significant decrease in resting muscle TAN and ATP content in both groups (ATP content in creatine group pre: 24.1 ± 0.8, post: 17.2 ± 0.5; and placebo group pre: 26.5 ± 1.1, post: 18.0 ± 0.6 mmol/kg dm; p<0.001). During and in recovery from ST on day 7, both groups had lower plasma ammonia (p<0.05), hypoxanthine (p<0.001) and urate (p<0.001) accumulation than on day 1 of ST. There was no improvement in 1-hr cycle distance performance after ST, but peak sustained power output increased in the creatine group and not in the placebo group after ST (p<0.05). Peak and mean power during a 30 s Wingate test increased significantly (p<0.05) after ST but there was no additional ergogenic effect of creatine supplementation. In conclusion, this study shows that 1) the efficacy of muscle creatine uptake was dependent on the percentage of Type IIB fibres, 2) creatine supplementation and maintenance (2 g/d) did not attenuate ATP or TAN loss during 7 days of ST, 3) ST decreased the accumulation of plasma products of adenine nucleotide degradation and improved 30 s sprint performance, and 4) creatine supplementation and ST did not improve I-hr cycle distance performance.

Mental fatigue impairs performance of physically-demanding tasks and increases rating of perceived exertion (RPE) while performing. However, there may be ways of overcoming such performance decrements. One possible method includes the use of attentionally focused instructions. Motor learning research has shown that externally focused instructions can lead to improved performance in comparison to internally focused instructions. The purpose of the present study was to investigate the moderating effect of attentional focus on the mental fatigue – endurance performance relationship as well as the mental fatigue – perceived exertion relationship. Undergraduate students (N = 78) completed two wall sit tasks to volitional failure, one before and one after the completion of a cognitive task. Half the participants were randomly assigned to complete a high cognitive demand task to induce mental fatigue (incongruent Stroop; HMF), while the other half performed a low cognitive demand task (documentary viewing; LMF) before the second wall sit. Immediately prior to the second wall sit, half the participants in each cognitive task group also received instructions to focus their attention either internally (INT) or externally (EXT) during the second wall sit. The main effect of mental fatigue (p < .001, d = .873) during the cognitive task and the main effect of attentional focus (p < .001, d = .883) during the wall sit task were significant, indicating effective manipulations. Results found no moderating effect of attentional focus on wall sit performance (p >.500) or RPE (p = .724). However, between-group analyses were conducted to probe the differences in performance between each group. Results indicated the HMF/INT group performed significantly worse than the LMF/EXT (p = .032) and trended towards performing worse than the HMF/EXT and LMF/INT groups (ps < .090). Significant differences in RPE were also seen between trials for the HMF/INT group (p = .009, d = .592) alone, suggesting detrimental effects of both mental fatigue and internal focus combined. Overall, the data indicate a potential moderating effect of internal attentional focus that may exacerbate the detrimental effects of mental fatigue on performance and RPE. / Thesis / Master of Science (MSc)

Shoulder injuries are a focus of work related musculoskeletal disorder (WMSD) research due to rising healthcare costs, an aging workforce, and long recovery times. Substantial research has been performed in the area of shoulder WMSDs and a number of risk factors have been implicated in their development; including static loads, repetition, and deviated posture. However, knowledge of underlying pathophysiological mechanisms is limited. Thermography provides a non-invasive technique that may offer clues to unknown physiological markers associated with injury development during job task performance. The objective of this study was to quantify anterior deltoid surface temperature changes as function of changing task demands. Skin surface temperature changes of the anterior deltoid, modified Borg CR-10 ratings, and endurance time during overhead static exertions until exhaustion for two work loads (15 and 30% MVC) and shoulder angles (90o and 115o) were quantified. Ten participants (5 males and 5 females) participated in the study and were free of confounding conditions (such as chronic or acute shoulder injury) and were required to meet body fat percentile requirements. Thermography showed that the higher shoulder angle had a reduced blood flow while there were no differences in temperature for exertion. Modified Borg ratings were not found to be well correlated with temperature values. The findings suggest that workers performing overhead work should minimize their deviated posture when available to prevent a high risk of developing a shoulder WMSD. / Master of Science

In a 1994 survey, on incidence rates of musculoskeletal injuries among private industries within the U.S, nurses ranked first nationally. Patient handling tasks are considered to be a precipitating factor in the development of many musculoskeletal injuries. For many decades personnel training has been an intervention widely used for the nursing back problem. Inconsistency regarding the effectiveness of many personnel training programs, lack of controlled research among existing studies, and a primary focus only on long term reduction of injury rates makes the interpretation of the success of personnel training programs a difficult one. This study is based on the assumption that, if a training program is to be effective as a means of reducing musculoskeletal injuries, it must first modify worker behaviors and biomechanical stresses to a measurable degree. This research investigated the effects of training (Video and Lecture/Practice) on modifying working behaviors and biomechanical stress. Two tasks were examined (wheelchair to bed and lift up in bed) with two types of assistance (one-person or two-person) and two levels of patient's dependence (semi-dependent or dependent). Changes in behaviors were examined immediately following training (1-2 days delay) and after a short period of time (4-6 weeks) and evaluated using the criteria of subjective ratings of exertion, and postural and biomechanical measures. Results indicated that training led to several significant changes in the knee, hip, elbow and torso angles, whole body, shoulders and low back RPE, shear forces and shoulder moments. No differences were observed in these measures after a short period of time, suggesting retention of the information presented during the training programs. Results as a whole suggest that training can positively affect the working postures and biomechanical stress during common patient handling tasks. All the postural changes and biomechanical measures were advantageous in terms of reducing musculoskeletal stress. It was also found that after a short period of time (4-6 weeks) still retained the information presented during the training programs. Training using a combination of lecture and practice in some cases achieved better results than Video-based training. / Master of Science

The Borg 6–20 rating of perceived exertion (RPE) scale is a common measure reported during exercise testing and training, and is usually taken as a response measurement to provide a subjective assessment of exercise intensity. A lesser used application of the scale is for regulating exercise intensity, referred to as its ‘production mode’. Recent research on this topic initiated by Eston et al. (2005) has led to a novel application of this procedure as a means of predicting an individual’s maximal oxygen uptake ( O2max) via a perceptually-regulated exercise test (PRET). The PRET could play a significant role in guiding exercise prescription and monitoring cardiorespiratory fitness levels in situations where the normal heart rate response is affected. The aim of this thesis is to develop further and test the integrity of the PRET technique. Firstly, a review of the evidence on the validity and reliability of the Borg RPE scale when used to regulate exercise intensity in healthy and unhealthy adults is presented, as to-date, no scholarly publication has synthesised the body of knowledge on this specific application of the scale. Subsequently, four studies were completed to investigate the effects of different methodological variations on the predictive capabilities of the PRET, including an examination (for the first time) of its utility among heart failure patients (Study 4). Study 1 re-visited the validity and reliability of the PRET technique utilising a modified protocol of differing durations (2 and 4 min bouts), with revised instructions and placing the graded exercise test (GXT) as the final trial during cycle ergometry. Superior results were observed to those reported in previous investigations (Eston et al., 2008; Faulkner et al. 2007; Eston et al., 2006) during the 3 min trial, further reinforcing the validity and reliability of this technique. Accordingly, Study 2 was the first to investigate the reliability and validity of a treadmill PRET protocol with a ceiling intensity of RPE 15, rather than RPE 17, and observed that a safer modified PRET (with practice) provides acceptably valid and reliable predictions of O2max in healthy adults. In addition, Study 3 extended the research thus far by investigating the PRET protocol during cycle exercise, once again with a ceiling intensity of RPE 15, and demonstrated that (with practice) a cycle-based PRET can yield reliable and valid predictions of O2max that compare favourably to previous investigations. Finally, given that the research employing a PRET has unanimously alluded to its likely value in clinical populations among whom heart rate as a physiological response to exercise is affected (e.g. via medication) and precluded as a means predicting O2max, Study 4 investigated the utility of a PRET in a beta-blocked population of heart failure patients. In the event, it was observed that a PRET (up to RPE 15) was too strenuous and needs to be capped at an intensity of RPE 13 in this population. In addition a continuous protocol seemed unsuitable due to its length and it was recommended that a discontinuous PRET protocol be investigated. Future research needs to investigate the utilisation of the PRET (i) in different exercise modes; (ii) determine the optimum number of practice trials required; (iii) whether a discontinuous or continuous protocol is more appropariate; (iv) whether the extrapolation should be made to RPE 19 or 20 and; (v) whether the PRET can be employed succesfully in other clinical populations.