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There are few return-to-activity protocols and functional tests specifically designed for a proximal hamstring rupture for athletic trainers to follow when clearing an athlete for return to activity. To address this problem, the purpose of this study is to describe and evaluate a return to activity protocol that includes functional testing for a post-surgical proximal hamstring rupture to assess readiness for return to activity. This case study collected data from a 20-year-old, 6ft 2in, 185lb (87.9 kg) collegiate heptathlete that ruptured his proximal hamstring that required surgical treatment. The student athlete’s (SA) return to activity process is evaluated and explained. The SA went through numerous function tests to determine return to activity status. The first testing session was conducted 8 months post-surgery. He was then re-assessed 4 months later. During testing, the SA also wore accelerometers to gather more quantitative data to identify gait abnormalities due to the injury. The first round of testing revealed greater strength in his left (affected) leg compared to his right (unaffected) leg. The SA was not able to complete all the tests during the first round of testing due to muscular fatigue and soreness, suggesting low muscular endurance at that point in time. Thus, he was not cleared to return to activity and continued to do rehabilitation exercises to increase the endurance of the hamstring muscles. The second round of testing was completed 4 months later which revealed that he had gained endurance in the hamstring muscles and his strength had increased. At this point, he was cleared for full return to activity. This return-to-activity protocol with specific functional tests could serve as a template for other athletic trainers who are seeking to return an athlete to full activity after suffering a proximal hamstring rupture (See Appendix I). MALS

The COVID-19 pandemic and subsequent shutdown and regulations have drastically altered the world of competitive sports. The global shutdown beginning in March 2020 put a significant strain on athlete's ability to train, as many fitness centers were closed to prevent disease transmission. When it was deemed that athletic competition was safe to resume, there were still strict regulations in place to support public health efforts. This retrospective study primarily aims to evaluate the effectiveness of COVID-19 safety regulations in competitive sports. Specifically, the successfulness to correctly implement social distancing guidelines is of high interest. A secondary aim of this study is to assess changes in workload during preseason training before COVID-19, during the time of heavily enforced COVID-19 regulations, and following strict COVID-19 restrictions, as workload can be a predictor of athletic injury. Participants in this study included Virginia Tech Women's Soccer athletes and data were analyzed from the first 9 preseason training sessions during the 2019, 2020, 2021 and 2022 seasons. Data were generated from participants wearing the STATSports Apex device during training. A custom MATLAB spatiotemporal program developed by the Williams Research Group was utilized to determine player proximity. Total distance (m) and high metabolic load (HMLD) (au), and high-speed distance (HSD) (m) metrics were analyzed to understand changes in participant workload. It was found that overall the Virginia Tech Women's Soccer Team's implementation of the guidelines was effective, as there were no invasion violations during the 2020 preseason sample. Master of Science The COVID-19 pandemic has forever changed the world as we know it. Competitive sports are no exception. The worldwide shutdown as a result of COVID-19 made it difficult for athletes to train while in isolation, as most facilities were closed to prevent disease transmission. When sports were able to continue again, there were still barriers preventing normal practices and competition. Athletes were asked to make every effort to maintain social distancing, even during training sessions. The main purpose of this study is to evaluate how well NCAA Division 1 Women's Collegiate Soccer players maintained social distancing during preseason practices. A secondary goal of this study is to uncover changes in workload from before COVID-19 (2019), during strict COVID-19 regulations (2020), and when COVID-19 restrictions had been less enforced (2021 and 2022). The reasoning for this is that how much work an athlete does can be indicative of risk for injury. If an athlete does significantly more work than usual, there is a higher risk of injury. This study will use global positioning systems (GPS) and measures that reflect workload collected from Virginia Tech Women's Soccer players. It was found that the players remained farther apart during the 2020 season due to the emphasis on social distancing, and that the workload will show a gradual increase to prevent injury. Overall, the study found that the COVID-19 regulations were effectively implemented among the Virginia Tech Women's Soccer Team in the 2020 preseason when restrictions were the highest.

In female college soccer players, there is no protocol for assessing fatigue. A total of 40 members of the Virginia Tech Women's Soccer team participated in the countermovement jump assessment to find a reliable way to gauge player fatigue and readiness in these athletes. These were tested by assessing the within and between-day similarity of a countermovement jump test as a measure of neuromuscular performance by comparing multiple jump heights during jumps performed within a single day and on separate days. Additionally, to determine the responsiveness of countermovement jump height as a marker of fatigue, we compared jump heights before and after activities thought to induce fatigue and competitive matches. All subjects wore a STATSports APEX unit that includes an 18Hz GPS, 952 Hz accelerometer, and 952 Hz gyroscope situated on the upper back over the second thoracic vertebra using a manufacturer-provided vest. After each training session or match, the data was downloaded using the manufacturer's software (APEXA). A custom MATLAB program was then used to calculate CMJ height from vertical acceleration. Results showed that CMJ heights were very reliable both within and between testing days. CMJ heights were found to accurately decrease following both high-load training sessions and a competitive soccer match. For both activities, the decrease in performance was dependent on the amount of load experienced. Lastly, CMJ height did not recover the day following high training load sessions. Across a training week, CMJ consistently decreased each day. This was followed by a recovery in performance following two off days. The results suggest that the use of a trunk-mounted, GPS-embedded accelerometer and a novel three-jump protocol is responsive to assess CMJ height. In addition, it is responsive to estimating fatigue following soccer activity. Master of Science In female college soccer players, there is no protocol for assessing fatigue. A total of 40 members of the Virginia Tech Women's Soccer team participated in the countermovement jump assessment to find a reliable way to gauge player fatigue and readiness in these athletes. We hypothesized that countermovement jump heights would not vary between jumps executed on the same day and on different days. We also hypothesized pre-training countermovement jump heights would vary across a 7-day training session with reductions dependent on the prior days' physical demands and would be reduced following a competitive soccer match, also dependent on each player's physical demands. These were tested by assessing the within and between-day reliability of a vertical jump test as a measure of performance by comparing multiple countermovement jump heights during jumps performed within a single day and comparing jumps on separate days. Additionally, to determine the feasibility of countermovement jump height as a marker of fatigue, we compared jump heights before and after activities thought to induce fatigue and competitive matches. All subjects wore a STATSports APEX unit that includes an 18Hz GPS, 952 Hz accelerometer, and 952 Hz gyroscope situated on the upper back over the second thoracic vertebra using a manufacturer-provided vest. After each training session or match, the data was downloaded using the manufacturer's software (APEX) and a custom MATLAB program was then used to calculate CMJ height from vertical acceleration. Results showed that CMJ heights were very reliable both within and between testing days. CMJ heights were found to decrease following both high-load training sessions and following a competitive soccer match. For both activities, the decrease in performance was dependent on the amount of load experienced. Lastly, CMJ height did not recover the day following a high training load sessions. Across a training week, CMJ consistently decreased each day. This was followed by a recovery in performance following two off days. The results suggest that the use of a trunk-mounted, GPS-embedded accelerometer and a novel three-jump protocol is reliable to assess CMJ height. In addition, it is feasible to estimating fatigue following soccer activity.

Team sports frequently use inertial measurement units (IMU) fixed at the scapulae for the quantification of athlete performance. Similar IMU are used in clinical settings for gait analysis and jump testing but are located at the center of mass (COM). For clinical methods of jump and gait analysis to be translated to sports related IMU, an investigation of the validity of measure from the scapulae should be assessed. The objective of the current study was to translate clinical methods of gait analysis and jump assessment to commercially available trunk-mounted accelerometers. The current study created a gait program to analyze and compile the gait data. Following completion of the gait program, the IMU (STATSports APEX) was investigated for validity against ankle accelerometers. Once the validity was determined, an application study evaluated the relevance of collecting gait data during a NCAA D1 Women's Soccer season. Similarly, the trunk-mounted accelerometer was validated against force plates to assess countermovement jump height. The final study assessed how both jump height and gait variables changed due to game-related decline in performance. This study provides evidence that trunk-mounted accelerometers are a valid tool for assessing temporal gait variables (ICCRight = 0.95 and ICCLeft = 0.96), CMJ height (ICCJH = 0.90) and flight time (ICCFT = 0.88). A longitudinal analysis of gait showed that StepL, StrideL, kleg, and postural variables changed regularly in pre-post comparisons of performance. Postural variables had more changes towards the end of the season. Root mean squares (RMS) of accelerations and angular velocities had the highest correlations to High Speed Running (HSR). Fractal step and stride length (StepLα and StrideLα) had the strongest correlation to Total Distance (Rstep = -0.29 and Rstride = -0.29), or Tot Dist. When comparing gait and CMJ analyses to detect game-related changes in performance, CMJ was more descriptive of fatigue. In a proof-of-concept study, pre-post changes in CMJ immediately before and after a game had a moderate negative correlation (R = -0.57) to Tot Dist. When the protocol changed to assess the differences between the days before and after the game, the correlation weakened to R = -0.27. Spatiotemporal and spring mass variables did not change, whereas postural variables appeared to improve. The current study has provided evidence that running gait could be used as an athlete monitoring technique, however more data needs to be collected to understand how running gait variables change with team-sports related fatigue. Doctor of Philosophy Trunk-mounted accelerometers have become widely popular in team sports such as soccer. Prior to their use in team sports, accelerometers were used in clinical settings to assess gait, and in some cases jump performance. Different from the trunk-mounted accelerometers, the clinical accelerometers were fixed on the lower back to approximate the position of the center of mass. Consequently, the methods to assess gait and jump performance using an accelerometer assume that the accelerometer is fixed on the lower back. For these methods to be translated to trunk-mounted accelerometers, the validity of the methods needs to be established. This paper investigated the validity of trunk-mounted accelerometers in evaluating gait and countermovement jump height. A season-long assessment of gait provided insight into the utility of monitoring gait in team sports athletes. Lastly, a comparison of gait to countermovement jump analyses helped to elucidate what the changes in gait indicate, and how team staff may effectively utilize that information. The trunk-mounted accelerometer (STATSports APEX) was valid in estimating gait and jump variables. The seasonal analysis showed that gait variables changed frequently throughout the season. The main variables affected described the step and stride length of the individual, the stiffness of the leg, and variables representing the variability in trunk movements associated with running. The variability in trunk movements were more perturbed towards the end of the season when players may be beginning to tire from continuous training and competition. In the final study, the jump analysis proved to be more representative of the player's state of fatigue than gait. The gait variables appeared to improve after exhaustive exercise. The apparent improvement in gait variables could indicate that the players recovered quickly from the exhaustive exercise, or that gait variables respond in a more complex fashion than jump variables. More data needs to be collected on how gait changes due to game-related fatigue in soccer players to better understand its effect on neuromuscular performance.

American football is one of the most popular sports in the United States. However, in comparison to other mainstream sports such as soccer and rugby, there is limited literature using scientific principles and theory to examine the most appropriate ways to monitor the sport. This serves as a barrier to American football practitioners in their development and implementation of evidence-based sport preparation programs. Therefore, the primary aim of this line of research (i.e., dissertation) is to illustrate the efficacy of commonly used athlete monitoring tools within the sport of American collegiate football, while proposing a systematic framework to guide the development of an athlete monitoring program. This aim was achieved through a series of studies with the following objectives: 1) to quantify the physical demands of American collegiate football practice by creating physiological movement profiles through the use of integrated microtechnology metrics and heart rate indices, 2) to determine the positional differences in the physical practice demands of American collegiate football athletes, 3) to examine which integrated microtechnology metrics might be used to most efficiently monitor the training load of American collegiate football athletes, 4) to demonstrate the suitability of using the countermovement jump (CMJ) to assess training adaptations in American collegiate football athletes through examining weekly changes in CMJ performance over the course of two 4-week periodized training blocks (8 weeks total), and 5) to examine the effect of acute fatigue on CMJ performance in American football athletes. The first study from this line of research quantified the physical demands of American collegiate football by position groups and found significant differences in both running based and non-running based training load metrics. In addition, the first study utilized a principal component analysis to determine 5 'principal' components that explain approximately 81% of the variance within the data. The second study utilized a univariate analysis and found significant changes in CMJ performance due the effect of time with significant improvements in CMJ 'strategy' variables over the training period. Finally, the third study used effects sizes to illustrate a larger magnitude of change in CMJ 'strategy' variables than CMJ 'output' variables due to effect of acute fatigue. Results from studies 2 and 3 suggest the importance of monitoring CMJ strategy variables when monitoring training adaptations and fatigue in American collegiate football athletes. This line of research provides practitioners with a systematic framework through which they can develop and implement evidence-based sport preparation programs within their own organizational context. In addition, this line of research provides practitioners with recommendations for which metrics to monitor when tracking training load in American collegiate football using integrated microtechnology. Finally, this line of research demonstrates how to assess training adaptations and fatigue using the CMJ within the sport of American collegiate football, while providing an empirical base through which the selection of CMJ variables can take place. Collectively, this line of research uses scientific principles and theory to extend the current literature in American collegiate football, while providing practitioners with a guide to athlete monitoring within the sport. Doctor of Philosophy American football is one the most popular sports in the United States. Despite its popularity, there is limited research using scientific principles and theories to examine ways to most effectively monitor the sport. Broadly, athlete monitoring refers to the process of providing informational feedback from the athlete to practitioners. This allows practitioners to make decisions informed by data. Therefore, this line of research (i.e. dissertation) aimed to use a variety of commonly used athlete monitoring tools to monitor American collegiate football athletes, while proposing a framework to guide in the development of an athlete monitoring program. This line of research consisted of a series of 3 studies. In study #1, it was found that integrated microtechnology units and heart rate sensors could be used to determine the physical demands of American collegiate football practice, as well as differences in the physical demands of practice by position group. In addition, a set of 5 training load constructs were found through which training load in American collegiate football athletes may be appropriately monitored. In study #2, it was found that countermovement jump (CMJ) strategy variables indicating how the jump occurred may provide more insight into strength and power training adaptations than CMJ output variables that indicate what occurred as a result of the jump in this highly trained athletic population. Finally, in study #3, it was found that CMJ strategy variables may be more sensitive to acute fatigue from a football-specific training session than CMJ output variables in American collegiate football athletes. Collectively, this research suggest that integrated microtechnology units, heart rate sensors, and the CMJ using a force testing platform may be used to monitor American collegiate football athletes. Moreover, this research suggests which variables to utilize when monitoring this population using these tools through the proposed athlete monitoring framework.

Injury risk reduction is an ever-evolving topic within an athletic environment. Consequences from an injury include participation time loss, financial, social, and personal costs. Coaching and medical staff strive to reduce the risk through various manners. Training load monitoring is one method that is utilized in injury risk reduction through global positioning systems (GPS) with statistical modeling. The purpose of this study was to investigate the external loads for training sessions and competition in starters versus non-starters; to determine if there were control chart violations associated with sustained injuries; and to determine whether in-season injuries were associate with one or more control chart violations. NCAA Division I female soccer players were recruited during the fall 2019 season. Participants were provided a STATSports GPS unit to wear during all practice and competition sessions to analyze the following variables: total distance, high metabolic load distance, sprints, accelerations, decelerations, and dynamic stress load (DSL). These variables were analyzed using statistical process control charts (SPC Charts) and Nelson Rules. Overall, there were 1,235 violations for the team, with the highest amount coming from DSL. Throughout the season, there were 16 time-loss injuries. Within the 3- and 7-day periods prior to injury, there were only two cases in which the injured athlete had more violations when compared to the team average. Therefore, SPC Charts were not a good indicator of injury risk prediction within this population. Future research includes reassessing these methods within a larger population and for a longer duration (i.e. several seasons). Master of Science Reducing the risk of injury in athletes is a focal point for many coaches, training, and medical staffs in collegiate athletics. The consequences of injury range from loss of playing time to financial and long-term health costs. Being able to reduce the risk of injuries not only has personal implications for the athlete but also relates to overall team success. Using global positioning systems (GPS) to track the amount of work done in training can possibly reduce injury risk. This study planned to investigate the workload in NCAA Division 1 collegiate female soccer athletes and if any injuries were sustained during both training and competition settings. The results suggest that statistical process control (SPC) charts and the Nelson Rules did not predict injury risk within this population. There is limited research that has used these tools. Future work can reassess these methods within larger collegiate athletic populations, over a longer period of time.

For years, heart rate (HR) kinetics have been used as an indicator of training status and fatigue. Slowed kinetics indicate poor fitness and/or fatigue. In this study it was determined that HR kinetics can be reliably estimated during modeled, quasi-binary, and dynamic exercise using cross-correlation analysis of HR and external work rate. Heart rate and running speed were cross-correlated yielding a cross-correlation function (CCF) and analyzed for its peak (CCFmax) and time delay (CCFlag). Modeled exercise data where the time constants for HR (τ) increased from 2-120 sec. yielded linear decreases in CCFmax (r2 = 0.9949) and linear increases in CCFlag (r2=0.9996). A strong linear relationship existed between CCFmax and CCFlag (r2=0.9989). Steady-state exercise data produced strong relationships between the calculated τ and CCFmax (r2=0.8736) and CCFlag (r2=0.9061), and CCFmax and CCFlag showed a positive relationship (r2=0.7753). CCFmax between repeated sprint trials (R2=0.9123) and super set trails (R2=0.9227) were very similar. These results suggest good repeatability for both quasi-binary activity and random activity. To assess validity, CCFmax values during the sprint trials were compared to two standard field tests of fitness (Beep and Man U tests). There were strong relationships between CCFmax and distances covered during the Beep (r2=0.7911) and Mann U tests (r2=0.7770). Lastly, the applicability of the CCF method was applied to dynamic exercise, using data collected from competitive soccer matches. For the field players, significant reductions in CCFmax occurred during the first and second periods of the match. There was a significant relationship between the total distance covered during the match and the decline in CCFmax (r=-0.4297, p

The purpose of this study was to determine the accuracy of distance measurements obtained using a Fitbit device compared to a highly accurate GPS-embedded accelerometer device. The participants of this study completed two, 18-hole rounds of golf on two different courses. Prior to each round, participants were fitted with Fitbit device worn on the wrist and a GPSports device secured to the lower back. The participants were eight student-athletes on the Virginia Tech Women’s golf team who completed the quantitative case study that assessed the accuracy of the Fitbit devices. The objective of this project was to provide those who play golf with a better understanding on whether or not a Fitbit can be trusted to provide accurate results when competing in a round of 18 holes of golf. A t-test was used to analyze the data once collected. Results of this study show signs that the Fitbit underestimates the distance traveled when compared with the GPS device. For future research we recommend using more specific ranges when comparing the two devices rather than just the two separate 18 hole rounds. MALS

Accelerometer data can be analyzed using a variety of methods which are effective in the clinical setting. Time-series analysis is used to analyze spatiotemporal variables in various populations. More recently, investigators have focused on gait complexity and the structure of spatiotemporal variations during walking and running. This study evaluated the use of time-series analyses to determine gait parameters during running. Subjects were college-age female soccer players. Accelerometer data were collected using GPS-embedded trunk-mounted accelerometers. Customized Matlab® programs were developed that included Gaussian continuous wavelet transform (CWT) to determine spatiotemporal characteristics, detrended fluctuation analysis (DFA) to examine gait complexity and autocorrelation analyses (ACF) to assess gait regularity. Reliability was examined using repeated running efforts and intraclass correlation. Proof of concept was determined by examining differences in each variable between various running speeds. Applicability was established by examining gait before and after fatiguing activity. The results showed most variables had excellent reliability. Test-retest R2 values for these variables ranged from 0.8 to 1.0. Low reliability was seen in bilateral comparisons of gait symmetry. Increases in running speed resulted in expected changes in spatiotemporal and acceleration variables. Fatiguing exercise had minimal effects on spatiotemporal variables but resulted in noticeable declines in complexity. This investigation shows that GPS-embedded trunk-mounted accelerometers can be effectively used to assess running gait. CWT and DFA yield reliable measures of spatiotemporal characteristics of gait and gait complexity. The effects of running speed and fatigue on these variables provides proof of concepts and applicability for this analytical approach. Master of Science Fitness trackers have become widely accessible and easy to use. So much so that athletic teams have been using them to track activity throughout the season. Researchers are able to manipulate data generated from the fitness monitors to assess many different variables including gait. Monitoring gait may generate important information about the condition of the individual. As a person fatigues, running form is theorized to breakdown, which increases injury risk. Therefore the ability to monitor gait may be advantageous in preventing injury. The purpose of this study is to show that the methods in this study are reproducible, respond reasonably to changes in speed, and to observe the changes of gait in the presence of fatigue or on tired legs. Three analyses are used in this study. The first method called autocorrelation, overlays acceleration signals of consecutive foot strikes, and determines the similarity between them. The second method utilizes a wave transformation technique that is able to determine foot contact times. The final method attempts to determine any pattern in the running stride. This method looks for changes in the structure of the pattern. Less structure would indicate a stride that is fatigued. The results showed that the methods of gait analysis used in this study were reproducible and responded appropriately with changes in speed. Small changes in gait were observed due to the presence of fatigue. Further investigation into the use of these methods to determine changes in gait due to the presence of fatigue are warranted.

Background Organized sports offer an opportunity to promote physical activity and healthy eating. However, current data suggest that youth sports settings may not necessarily provide these benefits. In one study, youth were sedentary nearly half of a soccer match and in another foods and beverages offered at different youth sporting events were found to be energy-dense with little nutritional value. Parents, coaches and their respective sports organizations have the capacity to support a positive sports environment by promoting nutritious foods and beverages as well as optimal movement. To date, there is little research available on physical activity and sports trends of younger audiences, as well as perceptions of coaches and parents of young children toward sports snacks and policies to support healthy eating. The goal of these three studies were to better understand the youth soccer setting as an opportunity to address healthy eating and physical activity. Study 1 Objective: Assess snack offerings of parents and coaches of young soccer players, and policies. Methods: Beverage and Snack Questionnaires were distributed among all parents (n=120) and coaches (23) participating in recreational under five (U5) and under six (U6) soccer. The questionnaires assessed: socio-demographic information; types, as well as frequency, of snacks and beverages offered to children; reasons for snack and beverage choices; and attitudes toward snack policies. Results: Of the 44 parents and 23 coaches that participated, nutrition was ranked as the number one factor in choosing snacks and beverages for children participating in soccer. Yet parents and coaches reported offering many low-nutrient dense foods to their children as snacks. Coaches were receptive to limiting snack options and recommending healthy alternatives. Study 2 Objective: Observe snack offerings for young, recreational soccer players at combined practices and games to determine nutrient content and energy density of the foods and beverages provided. Methods: Snack observations for multiple, randomly selected teams were recorded using an observational checklist by trained researchers following all scheduled combined practices/games. Mean values across all snack foods and beverages were computed for the following key nutrients: calories, protein, fat, carbohydrates, fiber, sugars, and sodium. Results: Offered snacks were high in sugar, contributing nearly 77% of recommended total sugar intake per day, and low in sodium, fiber, and protein. Study 3 Objective: Determine the level of physical activity among young soccer players. Methods: Six random U5 and U6 teams were selected with 36 eligible players to participate in accelerometer collection data. Participants wore magnetic running pouches containing an accelerometer for a combined practice/game totaling 60 minutes. Informed, voluntary consent was obtained from each child and parent. Results: For the entire recorded session, average speed was 2.2 km/hour, average distance was 1.3 miles. Children were considered sedentary 55.0% of the recorded time. Discussion and Conclusions Organized sports settings offer an ideal avenue for promoting health and wellness among youth athletes. The current culture unfortunately promotes unhealthy snacking and sub-optimal physical activity. While the location and sample sizes limit generalizability, our results support research conducted with older children and highlight the importance of nutrition education for parents and coaches, as well as the potential for snack policies and strategies to encourage more vigorous physical activity in youth sports settings. Master of Science

Poor diet and physical inactivity contribute to excessive weight and related diseases in the United States. Given the increasing rates of adult overweight and obesity among Americans, there is a need to develop and implement effective prevention and treatment strategies to decrease the public health burden of obesity-related chronic diseases. Faith-based organizations (FBOs) provide a unique setting and partnership opportunity for delivering evidence-based programs into communities that can be sustained. The federally funded Virginia Supplemental Nutrition Assistance Program Education (SNAP-Ed) delivered through Virginia Tech's Cooperative Extension and Family Nutrition Program, utilizes evidence-based programs to promote healthy eating and physical activity among limited income populations. The Virginia SNAP-Ed Volunteer Led Nutrition Education Initiative uses SNAP-Ed agents and educators to reach limited income populations by training and coordinating volunteers from communities to deliver nutrition education programs. However, these partnerships and training initiatives have been underutilized in FBOs across Virginia. This dissertation research describes four studies conducted to better understand how to facilitate collaborative partnerships and health-promotion programming initiatives between academic/extension educators and FBOs to build capacity and inform future initiatives within VCE. Study one conducted a literature review to examine FBO characteristics and multi-level strategies used to implement nutrition and physical activity interventions. Study two examined VCE SNAP-Ed agents' perspectives on FBO partnerships to deliver health programming. Study three assessed three FBOs and their member health needs to identify policies, systems and environments to support healthy lifestyles. Study four examined the acceptability of Faithful Families, a faith-based nutrition and physical activity program delivered in a rural church, and explored ways to build capacity for program sustainability through input from stakeholder partners. Results across studies yielded information which helped to identify and prioritize strategies for promoting FBO partnerships within VCE and helped to generate questions that merit further investigation to identify specific culturally relevant strategies for promoting health in FBOs. This exploratory body of research contributes to the field by describing relevant opportunities for academic sectors to partner with FBOs using participatory approaches to increase partnership readiness and build capacity to carry out and sustain health programs within faith settings. Ph. D.

BACKGROUND: The half-time (HT) period of a soccer match is viewed as a period for recovery. Completely inactive and passive HT has implications on metabolic responses and subsequent performance during the initial phases of the second half. PURPOSE: Determine the effects of an active rewarm-up, compared to a passive period, at halftime on various measures of performance during the first 15-minutes of the second half using global positioning system (GPS) units. Identify the effects of the active versus passive HT period, with CHO beverage supplementation, on blood parameters. METHODS: Crossover design study, twenty collegiate male soccer players participated in two 90-minute soccer matches with passive rest (CON) or a moderate-intensity rewarm-up (RWU) during HT with CHO supplementation. Subjects received five fingerstick blood samples throughout the match (BG) and four subjects had serum insulin/BG taken three times during the match. RESULTS: RWU had significantly (p

Studies have concluded that youth sports programs have a bias selection process in identifying player talent. Athletes that are identified as talented are more likely to be born in the first three months after the eligibility cut-off for a program's particular age group. This is referred to as the relative age effect (RAE) and has been identified in many youth sports. However, it is not known if the RAE carries over into elite, adult competition. The purpose of this study was to determine if the RAE exists in Olympic competition and to compare the RAE between genders, team vs individual sports, weight class vs non-weight class sports, and medalists vs non-medalists. Data on Olympians competing in the 2012 London and 2016 Rio de Janeiro Olympics were gathered from publicly available databases. Lorenz curves were constructed and Gini coefficients calculated to detect unexpected distributions of birth months. In addition, linear regression was used to determine a directional distribution. A negative Gini coefficient and a statistically significant negative slope of the birth month distribution suggested the existence of a RAE. The results showed that there was a RAE in Olympic competition. For all athletes, the Gini coefficient was -0.0324 and the slope of -0.0014 fraction of athletes born per month. Within specific sports, the RAE varies considerably with some showing a positive RAE. Further, the RAE in Olympic athletes does not seem to be influenced by gender, type of team or success of the athlete. Master of Science

Tennis is a competitive sport attracting millions of players and fans worldwide. During a competition, the physical component crucially affects the final result of a match. In field sports such as soccer physical demand data are collected using the global positioning system (GPS). There is question regarding the validity and reliability of using GPS technology for court sports such as tennis. The purpose of this study is to determine the validity and reliability of GPS to determine distances covered during simulated tennis movements. This was done by comparing GPS recorded distances to distances determined with a calibrated trundle wheel. Two SPI HPU units were attached to the wheel Four different trials were performed to assess accuracy and reliability: distance trial (DIST), shuttle run trial (SHUT), change of direction trial (COD) and random movement trial (RAND). The latter three trials are performed on a tennis court and designed to mimic movements during a tennis match. Bland-Altman analysis showed that during all trails, there were small differences in the trundle wheel and GPS derived distances. Bias for the DIST, SHUT, COD and RAND trails were -0.02±0.10, -0.51±0.15, -0.24±0.19 and 0.28±0.20%, respectively. Root mean squared (RMS) errors for the four trials were 0.41±0.10, 1.28±0.10, 1.70±0.10 and 1.55±0.13%. Analysis of paired units showed a good reliability with mean bias and RMS errors

Trunk-mounted monitoring equipment like GPSports SPIHPU units are designed to use global positioning (GPS), accelerometer and heart rate monitoring to evaluate the physical demands of an activity. A medical staff might also consider markers such as running symmetry in evaluation of injury occurrence and rehabilitation. A running symmetry is a ratio of the synchronization of the right and left lower limbs during the gait cycle. An asymmetry due to, a pathology or musculoskeletal injury, results in abnormal loading on the foot that may be detected by trunk-mounted accelerometry. The aim of this study is to evaluate the ability of SPIHPU units to detect running asymmetry. Subjects wore the HPISPU units (100Hz, 16g tri-axial accelerometer, 50Hz magnetometer) while engaged in various running activities. In the first study, artificially inducing a leg length discrepancy led to a difference between running symmetry scores. This discrepancy was confirmed using individual accelerometers attached to the lower leg near the foot. Next, varying running speed did not result in differences in running symmetry. However, the SPIHPU units did detect a running asymmetry between fatigued and non-fatigued conditions. Finally, two case studies showed that the units could identify asymmetry immediately after a lower leg injury and during rehabilitation of anterior cruciate ligament reconstruction surgery. The results of this study show that the HPUSPI units can be reliably used to monitor running symmetry and to detect asymmetrical gait patterns. Master of Science

Snacking behavior has changed dramatically over the past few decades, with snacking frequency reaching upwards of three times per day and comprising 27% of daily calorie intake. Research has shown that the largest food groupings from snacks are grain-based desserts, sweetened beverages, and salty snacks. Previous studies have also shown that children are influenced by their peers. Youth sports are a very popular venue for children and opportunity for physical activity, with soccer becoming one of the most popular sports among young children in the US. Youth sports, especially soccer, can be a powerful tool for promoting physical activity and healthy eating for overall health and obesity prevention. The goal of this study was to examine the nutrition composition of snacks and beverages offered to young children within a soccer league. The study utilized a cross-sectional observational study of snack foods and beverages offered to children participating in a voluntary youth soccer league in southwest Virginia. Snacks offered to children in the under-five (U5) and under-six (U6) years of age categories were observed during weekly matches using an observational checklist reflecting commonly consumed snack foods and beverages. The checklist included brand name, size of food item/beverage, and number of children (by gender) for each team observed. Undergraduate and graduate nutrition students were trained as observers to assess snacks that were offered, specifically visual item identification and portion size estimation. Food items were then classified into different food and beverage categories, including: sugar-sweetened beverages (SSBs) and 100% fruit juices; water; dairy (beverage); fruits; savory (salty) snacks; grain-based desserts; candy and dairy (food). Nutrition information was gathered for each food item and beverage and entered into a database: calories, carbohydrates, protein, fat, saturated fat, sodium, sugar, fiber, vitamin C, iron and calcium. Descriptive statistics were then computed for all nutrients by all snacks combined and by snack category across all observations. Snacks were also compared to the Smart Snacks in Schools nutrition standards. Across all teams there were a total of 687 items offered to the children: 253 beverages and 434 foods. They offered a mean of 205 calories per child. The most popular beverages were SSBs. The most popular snacks were grain-based desserts (136, 31.3% of all snack foods), followed by fruit (124, 28.5%) and savory snacks (117, 26.9%). No vegetables were served during the observations. Snacks within the savory snack item category provided the most calories per child at 63, followed by grain-based desserts, 58. When offered and served with beverages, snacks offered with fruit had a more favorable nutrition profile with lower mean kilocalories, lower sodium, and lower sugars than snacks without fruit. They were also more likely to meet the Smart Snacks in School nutrition standards: 65.4% compared to 25.6%. Only 44.4% of all snack foods and beverages taken by youth players met the smart snacks standards. Categorically, 67.6% of all grain-based deserts, 100% of all candy and 100% of all dairy beverages taken by youth players did not meet the smart snacks standards. Further research is warranted to identify motivating factors for providing unhealthy snacks and beverages to youth during sporting events. There are several limitations, including generalizability of this sample, however the study provides novel insight into snacks offered to young children during recreational soccer and can help inform future strategies and interventions to promote healthier snacks. Master of Science

Bone health in the context of two common maladies, osteoporosis and obesity, has spurred research in the area of physical activity (PA) and bariatric surgery (BarS). Objectives: To examine: 1) relationships between PA and the skeleton utilizing the peripheral Quantitative Computed Tomography (pQCT) and Dual-energy X-ray Absorptiometry (DXA) in pre-menopausal women; 2) effects of adjustable gastric banding (AGB) vs. Roux-en-Y gastric bypass (RYGB) surgeries on pQCT and DXA measures; 3) 6-month time course changes on serum biomarkers of bone turnover and associated adipokines induced by AGB vs. RYGB. Methods: Standard DXA and pQCT measurements were taken for all subjects. PA tertiles (PA-L, PA-M, PA-H) were based on a calculated average MET-min/day determined from 4-d self-reported PA and pedometer step counts. For BarS subjects, bone measurements were taken pre-surgery, 3- and 6-months post-surgery along with serum (or plasma) from fasting blood draws, with ELISA assays for total OC, undercarboxylated OC, CTx, adiponectin, and leptin. Results: Minimal DXA differences between the highest and lowest PA tertiles were seen, while pQCT tibial measures and polar strength-strain index (SSIp) indicated differences along the tibial shaft. Comparing the two instruments and adjusting for BMI, the DXA leg and hip BMD and BMC showed differences (p

Obstructive sleep apnea (OSA) is common in older U.S. adults and the prevalence is anticipated to rise in this age group along with obesity, a prominent risk factor for OSA. Recently, OSA was determined to be highly prevalent among patients with abdominal aortic aneurysm (AAA) disease. Objectives: Examine associations between OSA risk and physical activity (PA), metabolic syndrome (MetSyn), and exercise responses to cardiopulmonary exercise testing (CPET) in elderly patients with AAA disease. Methods: Elderly patients (n=326 for Studies 1 and 2; n=114 for Study 3) newly diagnosed with small AAAs (aortic diameter "2.5 and < 5.5 cm) were recruited. Data collection for all participants included: extraction of medical history and drug information from medical records; completion of a physical examination to assess resting vital signs and anthropometrics; fasting blood draw for several biochemical analyses; completion of a cardiopulmonary exercise test (CPET); and completion of interviews and questionnaires for health history, PA, and OSA risk. Results: 57% of subjects were High-risk for OSA and 17% were classified in the highest-risk Berlin Risk Score (BRS) 3 group; these subjects reported fewer blocks walked/day, flights of stairs climbed/day, and expended fewer Calories when engaged in these activities compared to Low-risk counterparts, independent of obesity. Among those at High-risk for OSA, 45% had MetSyn. Subjects with the highest BRS also had the highest prevalence of MetSyn and values for the MetSyn component biomarkers. Exercise capacity and physiological responses at rest, during exercise, and recovery were similar between groups at High- and Low-risk for OSA. Conclusions: Reduced levels of PA among elderly AAA patients at High-risk for OSA could have unfavorable implications for cardiovascular disease (CVD) risk and all-cause and CVD mortality. Subjects demonstrating the most clinical symptoms of OSA showed a significantly higher prevalence for MetSyn and several of the biomarkers that determine MetSyn. In clinical practice, the BRS may be useful for identifying those AAA patients at increased risk for both OSA and MetSyn. Ph. D.

Aim: The purpose of this study was to investigate docosahexaenoic acid (DHA) ingestion on muscle damage and inflammation during the first two weeks of a novice resistance training (RT) program. Methods: This study was a placebo-controlled, double-blind design. Forty-one healthy untrained males between the ages of 18 and 28 years consumed 2,000 mg/d of either DHA or corn oil (PCB) for 44 days including a 28 day loading period. Serum fatty acids were analyzed to determine treatment efficacy. During the 17 day training period, an acute eccentric exercise bout was implemented followed by a full-body RT regimen thrice weekly. Six fasted blood draws (days 1, 2, 4, 7, 12, and 17) during this exercise period were analyzed for creatine kinase (CK) and C-reactive protein (CRP). Maximum isometric strength (ISO) of the elbow flexors, delayed onset muscle soreness (DOMS), and range of motion (ROM) were measured on day 1 prior to exercise and also on days 2, 3, 4, 7, 12, and 17. Results: The CK response and the area under the curve (AUC) analysis for DOMS trended to decrease in the DHA group in comparison to placebo (p=0.0925 and p=0.0536, respectively). Treatment showed no effect on CRP levels. DHA supplementation significantly increased serum DHA by 380% as a proportion of total fatty acids (p

Creatine kinase (CK) primarily serves as an energy buffer assisting in regulating ATP homeostasis through synthesis of ATP from ADP and phosphocreatine (PCr). This enzyme is bound in the sarcomere near sites of ATP consumption via acto-myosin ATPase (A‧M‧ATPase) and research in cardiac muscle has found that PCr can alter contractile performance (maximal isometric force and Ca²⁺ sensitivity). Based on this evidence, CK and A‧M‧ATPase may be coupled in skeletal muscle. Therefore the purpose of this investigation was to determine the influence of the CK system on contractile performance and energy utilization in skeletal muscle. When skinned fibers (membrane removed) were provided a limited supply of [ATP] (0.1 mM), this resulted in increased Ca²⁺ sensitivity. The addition of PCr to low ATP solutions restored Ca²⁺ sensitivity and allowed normal isometric force generation across a range of [Ca²⁺] via ATP synthesis by CK. This was also possible with only CK reaction substrates (ADP, PCr) in the absence of ATP. Based on these findings, endogenous CK activity in glycerol skinned skeletal muscle fibers is sufficient to permit normal function of the contractile apparatus. Energy utilization was studied by indirect assessment of ADP production. Decreased net ADP production as measured by NADH fluorescence revealed endogenous CK was able to convert ADP produced by A‧M‧ATPase to ATP in skeletal muscle across a range of both [Ca²⁺] and [ATP]. This was confirmed directly via high-performance liquid chromatography measurements of ATP and ADP by showing that skinned skeletal muscle bundles have sufficient endogenous CK activity to produce ATP from substrates (ADP, PCr) and the ability to maintain low [ADP] in the presence of PCr. This study adds to the evidence for specific compartmentation of CK near sites of ATP utilization and contributes to the body of knowledge on contractile performance in skinned skeletal muscle fibers. By showing how changing demands on skeletal muscle (through increased Ca²⁺) alters force production and Ca²⁺ sensitivity, these findings lend support for the importance of endogenous CK as a pathway of ATP regeneration in skeletal muscle. Ph. D.

A compelling mystery in the study of exercise is mechanisms of skeletal muscle fatigue. Broadly described, muscle fatigue is the uncomfortable sensation that particular muscle groups are shutting down and muscle force production cannot continue. More specifically, muscle fatigue is defined as an activity-induced inability to continue to produce a desired level of force. Several groups suggest that a major cause of force loss during fatigue is reductions in the rates of sarcoplasmic reticulum (SR) calcium (Ca2+) release and uptake. These changes result in diminished contractile machinery activation, reduced force production and slowed relaxation. During exercise, adenosine 5'-triphosphate (ATP) is the energy currency that is used to support force production. As a result of ATP hydrolysis and re-synthesis, adenosine diphosphate (ADP) and adenosine monophosphate (AMP) levels rise. AMP kinase (AMPK) is an enzyme that becomes activated as a result of increased AMP levels. It is thought to function as a metabolic "master switch" within the muscle and plays a major role in carbohydrate and fat metabolism. Once AMPK is activated it regulates several ATP consuming and producing pathways. The overall objective of this project was to determine if increased metabolism during exercise contributes to SR Ca2+ dysfunction during fatigue. If this is true, artificial activation of AMPK via 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) should induce changes in SR function that are qualitatively similar to those caused by fatigue. In study 1, mice were injected with 0.85 mg/kg AICAR (or saline solution) and both gastrocnemius muscles were removed one hour later. In study 2, EDL muscles were placed in a muscle bath and incubated in AICAR (4mM) or stimulated to fatigue. Glycogen, glucose-6-phosphate (G-6-P), ATP, ADP, and phosphocreatine (PCr) were examined in all groups of muscles. Alterations in SR calcium uptake and release rates due to the presence of AICAR were also studied as a likely cause of muscle fatigue. AICAR treatment in vivo did not alter muscle glycogen, glucose, ATP, ADP or PCr concentrations. However, G-6-P levels were increased by 137%. This was accompanied by a 36% reduction in the SR Ca2+ uptake rate and a 42% reduction in Ca2+-stimulated Ca2+ ATPase activity as well as 13-15% reductions in the rates of Ca2+ release. These changes were not associated with SR Ca2+ pump content. Administration of AICAR in vitro also increased G-6-P content (200%) without altering the concentrations of glycogen, glucose, G-6-P, ATP, ADP or PCr. AICAR decreased SR Ca2+ uptake rate by 28% and the rate of Ca2+ release by 16%. For comparison, fatiguing stimulation reduced the rates of SR Ca2+ uptake and release by 31 and 41%, respectively. Taken together, these results indicate that when administered to skeletal muscle both in vivo and in vitro, AICAR evokes metabolic stress. More importantly, activation of AMPK alters skeletal muscle SR function to an extent that is qualitatively similar to that caused by fatiguing activity. At present, it is not clear how AMPK activation causes changes in SR function. However, the present finding is consistent with the notion that metabolic stress caused by exercise, affects SR function. This, in turn, leads to force loss but reduces energy demand and protects the cell from ATP depletion during maximal contractile activity. Master of Science

The purpose of this research was to identify the design characteristics and attitudes that impact the use of snowboarding helmets and to test statistically a proposed conceptual framework for identifying perceived importance of functional, expressive, aesthetic, and regulatory (FEAR) needs of snowboarding helmets for current snowboarders. Data for this study was collected online. The final sample was composed of 391 participants, which represented a 13.67% response rate. Multiple comparisons were used to examine mean differences among the FEAR variables, as well as attitudes toward helmet use. A multiple linear regression was used to test four proposed hypotheses. The results of hypotheses revealed that there was an impact between attitudes toward helmet use and perceived importance of functional needs, but this relationship depended on the level of expressive needs, aesthetic needs, and helmet usage. The typical impact of functional needs on attitudes toward helmet use was positive (slope = .013) when all variables were at their respective means (Hypothesis 1). Hypothesis 2 tested to see if there was an impact between attitudes toward helmet use and perceived importance of expressive needs, but again, this relationship depended on the level of functional needs and helmet usage. The typical impact of expressive needs on attitudes toward helmet use was positive (slope = .014) when all variables were at their respective means. Similarly, the impact between attitudes toward helmet use and the perceived importance of aesthetic needs was dependent on the level of functional needs and helmet usage. The impact of aesthetic needs on attitudes toward helmet use was typically negative (slope = -.012) when all variables were at their respective means (Hypothesis 3). Finally, Hypothesis 4 looked at the impact between attitudes toward helmet use and the perceived importance of regulatory needs. Unlike the other three hypotheses, this relationship did not depend on any other variables. The impact of regulatory needs on attitudes toward helmet use was positive, and the strength of association was .010. Although hypothesis 1-3 were substantially supported, and hypothesis 4 was fully supported, from a statistical point of view, the interaction effects between the independent variables (i.e., FEA needs) and the covariate (i.e., helmet usage) limit the findings, so we can not really state that the hypotheses were supported. However, based on information obtained from the respondents in this study, the application of a FEAR needs assessment of snowboarding helmets could help to enhance the overall performance of snowboarders. In other words, the improvement of helmet functionality, expressive qualities, aesthetic attributes and regulatory needs would provide a more enjoyable snow activity to participants. Thus, the conceptual framework of the perceived importance of FEAR needs would be acceptable to understand the attitudes toward helmet use among snowboarders. Ph. D.

Increased calcium-activated calpain proteolysis in the sarcolemma membrane is thought to be a primary mechanism in the pathophysiology of Duchenne Muscular Dystrophy (DMD). However, few studies have tested this possibility prior to the overt signs of the dystrophy. The purpose of this study was to test the hypothesis that there is greater calpain content and total relative calpain activity in membranes obtained from dystrophic (mdx; mdx:utrophin-deficient (mdx:utrn-/-)) compared to wildtype (wt) mouse skeletal muscles during maturation at ages 7- and 21-d,and at a post-maturation age of 35-d. Calpain activity was determined as the calcium-dependent cleavage of the flurogenic substrate SLY-AMC, and content was determined by Western analysis with an anti-calpain antibody. There were several intriguing findings: 1. There was an inverse relationship between calpain content and relative activity in the whole muscle in both wt and mdx mice from age 7- to 35-d: calpain content decreased, and relative calpain activity increased as the mice aged. This suggests a similar role for calpain in both genotypes, which might relate to specific maturation processes, possibly up to age 21-d. Although the inverse relation was evident at 35-d, the targets for calpain in mdx compared to wt likely differed. 2. The increased relative calpain activity in the membrane fraction of mdx mice at age 35-d (26.73 Arbitrary Units, (AU)) compared to that of age 7- (4.9AU; p

Duchenne muscular dystrophy (DMD) is a severe and fatal muscle wasting disease characterized by a high mutation rate in the gene that encodes the membrane-associated protein dystrophin that results in absence of expressed protein. Although the primary genetic defect for DMD is known, the mechanisms that initiate the onset of DMD are not currently understood. This study tested the hypothesis that pathophysiological processes involved in DMD could be identified by the global expression of mRNA in maturing dystrophin- and utrophin-deficient mouse (mdx:utrn-/-) muscles. Two potential dystrophic onset mechanisms targeted for analysis were (1) disrupted expression of calcium handling proteins; and, (2) increased expression of immune response markers. An mRNA expression profile was developed following isolation of total RNA from control and mdx:utrn-/- triceps surae (TS) muscles at ages 9-10 and 20-21 days using Affymetrix® Mu74Av2 GeneChips®. Compared to control, the mRNA expression profile in mdx:utrn-/- muscles revealed there was a 3-fold increase in the number of gene transcripts differentially expressed more than 2-fold (53 transcripts at ages 9-10 days; 153 at ages 20-21 days). However, there were no changes in the mRNA transcripts for calcium handling proteins. In distinct contrast, there was up-regulation of transcripts that corresponded to an immune response (40 transcripts), extracellular matrix activity (14), and proteolysis (8). Up-regulation of several transcripts corresponded to cytokines and their receptors (11), chemokines and their receptors (5), and lymphoid and myeloid markers (16) suggesting that dystrophic muscle is susceptible to invasion by macrophages, leukocytes, B- and T-cells. These results are consistent with several reports (Spencer et al., 1997; Chen et al., 2000; Porter et al., 2002; Porter et al., 2003a; Porter et al., 2003b; Porter et al., 2004) that indicate the immune system may play an important role in the early pathophysiology of DMD. Understanding the functional aspects of an immune response in DMD onset should lead to more effective therapeutics. Master of Science

Duchenne Muscular Dystrophy (DMD) is a severe X-linked progressive muscle wasting disease resulting from the absence of the membrane-associated protein dystrophin and the secondary components of the dystrophin-glycoprotein complex. Although the genetic basis of the disease has been known for over 15 years, the onset mechanism of the disease is not yet known and no treatment is yet available to significantly increase the lifespan of DMD patients. Increased levels of intracellular calcium have been noted in dystrophic muscle (Turner et al., 1991) and increased intracellular levels of calcium in skeletal muscle lead to increased levels of calcium-dependent proteolysis (Zeman et al., 1985). Increased levels of calpain, a calcium-dependent protease have been reported as early as age 4 weeks in mdx (dystrophin-deficient) mice (Spencer et al., 1995). Increased calpain activity has been demonstrated in mdx myotubes (Alderton et al., 2000a). There is also evidence of a role for calpain in DMD, but the contribution of calpain activity to the onset of DMD has not yet been determined. The purpose of this study was to test the hypothesis that increased calpain activity contributes to the onset of DMD in maturing (birth to weaning) dystrophic skeletal muscles and to determine if increased calpain activity was due to the relative distribution of calpain and calpastatin, calpain's endogenous inhibitor. Calpain activity was assessed in quadriceps and diaphragm muscle homogenate supernatant and pellet fractions from C57BL/6 control and mdx mice at ages 7, 14, and 21 days. Total calpain and calpastatin content were determined by Western analysis. In both the quadriceps and diaphragm samples, calpain activity in the supernatant increased with age. There was a significant increase (47.7%; p

Cancer cachexia is a debilitating, paraneoplastic syndrome commonly associated with late stage malignancy. It is estimated that ~25% of cancer-related deaths are due directly to complications arising from cachexia (Barton, 2001). Cachexia manifests as severe body wasting, primarily due to the loss of skeletal muscle mass. This study tested the hypothesis that muscle atrophy associated with cancer cachexia could be attenuated by using a unilateral, functional overload (FO) model applied concurrently with tumor development. To accomplish this, Morris hepatoma MH-7777 cells were implanted in adult female, Buffalo rats (n = 12) and allowed to incubate for 6 weeks. FO surgeries (n = 12) were performed five days prior to MH-7777 cell implantation. Over the course of six weeks, healthy, age, sex and strain-matched, vehicle-injected rats (n = 12) gained ~5% of body weight compared to tumor-bearing rats that lost ~6% of body weight when adjusted for tumor mass. Tumor-bearing animals experienced significant atrophy to gastrocnemius, tibialis anterior, extensor digitorum longus, plantaris and diaphragm muscles. FO successfully reversed plantaris muscle atrophy in cachectic, tumor-bearing rats (n=5). FO plantaris masses were ~24% larger than contralateral controls. However, this hypertrophic response was not as great as FO plantaris muscles from healthy, sham-operated controls (~44% larger than contralateral controls, n=5). FO plantaris muscles from tumor-bearing rats had ~1.5 fold increase in myonuclei/fiber ratios compared those of sham-operated, tumor-bearing controls (n = 6). Therefore, cancer cachexia did not prevent myonuclear accretion necessary for skeletal muscle hypertrophy. Little data exists on adaptations to myosin heavy chain (MHC) isoforms in cachectic skeletal muscle. Plantaris muscles from tumor-bearing rats displayed decreased percentages of MHC type I compared to plantaris muscles from vehicle-injected controls (7% vs. 3%, respectively). However, FO plantaris muscles from tumor-bearing rats had an increased percentage of MHC type I and decreased percentage of MHC type IIb compared to sham-operated tumor-bearing rats, adaptations commonly seen in trained muscles. Therefore, cancer cachexia did not prevent the capability of skeletal muscle to respond normally to hypertrophic stimuli. This study also attempted to characterize a mechanism responsible for the hypertrophic response, increased myonuclei/fiber ratio and transition toward a slower MHC profile in FO plantaris muscles from tumor-bearing rats. Recently, the Ca2+/calmodulin-dependent protein phosphatase, calcineurin, has been suggested as a critical factor regulating skeletal muscle growth and fiber-type dependent gene expression (Chin, 1998; Wu, 2000; Olson, 2000; Otis, 2001). The protein content of the catalytic subunit (CaNa) and the regulatory subunit (CaNb) of calcineurin were unchanged in plantaris muscles from tumor-bearing animals compared to healthy controls. Furthermore, total and specific (normalized to CaNa protein content) calcineurin phosphatase activity were not altered in any group. Therefore, calcineurin activity did not appear to be associated with the regulation of the morphological and physiological response of hypertrophying plantaris muscles in cachectic, tumor-bearing rats. Overall, this study indicated that atrophied plantaris muscles from tumor-bearing animals have a reduced capacity to hypertrophy potentially due to a decreased myonuclei/fiber ratio. Furthermore, it is unlikely that changes to mass and MHC isoform expression are associated with calcineurin phosphatase activity. Ph. D.

In this investigation, skeletal muscle sarcoplasmic reticulum (SR) was purified from female Sprague Dawley rats (200-250 g). SR samples were subjected to two different biochemical glycogen-extraction protocols. The results suggest that both amylase and removal of EDTA (No-EDTA) from the homogenization and storage buffers reduced the amount of glycogen associated with the SR. Both of these treatments failed to impair SR calcium (Ca2+) handling when assayed under conditions where exogenous ATP was added and utilized for SR Ca2+ transport. In fact, these treatments seemed to cause a small increase in both SR Ca2+-uptake and release rates under these assay conditions. As expected, glycogen phosphorylase content was reduced as a result of glycogen extraction in the presence of amylase, however this was not the case for No-EDTA samples. Interestingly, many other proteins differed in content after glycogen extraction. These treatments resulted in a greater recovery of the sarco(endo)plasmic reticulum Ca2+ adenosine triphosphatase (SERCA) and a substantial loss of glycogen phosphorylase and glycogen debranching enzyme (AGL) in amylase-treated samples. Creatine kinase (CK) and pyruvate kinase (PK) contents were increased as a result of both glycogen-extraction conditions. It was imperative to consider these altered protein contents while analyzing the data and assessing the effects of glycogen extraction on SR Ca2+ handling. After normalizing to SERCA content, only No-EDTA samples had higher adenosine triphosphate (ATP)-supported SR Ca2+-uptake rates compared to control samples. For endogenously synthesized ATP-supported SR Ca2+-uptake experiments, normalizing data to protein content (either CK and SERCA or PK and SERCA) revealed that amylase-treated samples had lower SR Ca2+-uptake rates, compared to control samples. Although not significant, SR Ca2+-uptake rates for No-EDTA samples were also lower than control samples. These data suggest that changes in endogenously supported SR Ca2+-uptake due to glycogen extraction affected the source of ATP synthesis (either PK or CK), the effectiveness of energy utilization for Ca2+ transport (SERCA), or altered the metabolic channeling properties. Ph. D.

Duchenne's muscular dystrophy (DMD) is a debilitating disease that affects approximately 1 in 3500 boys, with many DMD patients dying before the age of 20 due to cardio-respiratory complications. DMD is the result of defects in the gene that encodes dystrophin, an integral muscle membrane protein. Although the genetic defect has been identified, the relation between the absence of expressed dystrophin and the mechanisms leading to its onset are still unclear. One possibility is that disrupted calcium (Ca²⁺) handling by the sarcoplasmic reticulum (SR) leads to an increased cytosolic Ca²⁺ concentration that activates proteolytic and apoptotic pathways that initiate muscle fiber death. However, little is known about the role of disrupted SR function in the onset of DMD. The purpose of this study was to test the hypothesis that altered calcium cycling by the SR could contribute to elevated cytosolic Ca²⁺ levels in the early stages of DMD, and thereby account for the onset of disease pathogenesis. Rates of SR Ca²⁺ uptake and release were determined in quadriceps muscles obtained from maturing dystrophic and control mice prior to the overt signs of the disease at ages ~9 and 21 days. In addition, the content of several key Ca²⁺ handling proteins, including two isoforms of the sarco(endo)plasmic reticulum ATPase pump (SERCA 1 & 2), ryanodine receptor type 1 (RyR1), parvalbumin, and calsequestrin were determined by Western analysis. Two dystrophic mouse models were used, the mdx mouse which lacks dystrophin, and the mdx:utrophin-deficient (mdx:utrn-/-) mouse which also lacks utrophin, a protein homolog of dystrophin. The rate of SR Ca²⁺ uptake in quadriceps muscles of mdx/utrn-/- mice aged 21 days was 73.1% and 61.3% higher than age-matched control and mdx muscles, respectively (p < 0.05). There was no difference in SR Ca²⁺ release rates between the genotypes at either age. There were significant increases in the content of each of the calcium handling proteins with age (p < 0.05), but no significant differences were detected between genotypes at either age. These data demonstrate the Ca²⁺ release rates of dystrophic SR are not compromised, but suggest the increased uptake rates of mdx:utrn-/- SR may be an adaptation to increased cytosolic calcium levels, and/or be due to changes in intrinsic SERCA function and/or regulation. The role of increased SR Ca²⁺ uptakes rates in onset of DMD pathogenesis can not be directly determined from the present data; therefore it is suggested that future studies directly assess cytosolic Ca²⁺ concentration and examine the role of SERCA regulatory proteins in intact fibers obtained from mdx:utrn-/- muscles at age 21 days. Master of Science

Fatigue during exercise is associated with reduced muscle glycogen. However, evidence linking glycogen content to fatigue is lacking. In this study we examined whether reduced muscle glycogen content limited SR function or muscle performance. Two groups of female Sprague-Dawley rats were fasted for 24 hr and exercised for 90 min to reduce muscle glycogen; rats fasted after exercise formed the low glycogen (LG) group. Rats in the high glycogen (HG) group were allowed free access to food and a 5% sucrose solution. The LG group had 42% less muscle glycogen and 90% less glycogen associated with the sarcoplasmic reticulum (SR) than the HG group. Notably, time to exhaustion during a subsequent treadmill run (21 m/min at 10% grade) was markedly lower in the LG group (35 vs. 166.75 min). Despite less glycogen, the LG group had a higher SR Ca2+ uptake rate (45%) and Ca2+-stimulated ATPase activity (51%) possibly due to a 33% greater SERCA content. Surprisingly, in situ gastrocnemius initial twitch and tetanic forces were not different between groups although the rates of relaxation were higher in the LG group. The force responses to fatigue-inducing stimulus trains (20 Hz for 333 ms every 1 sec for 30 min) also were similar for both groups as were twitch and tetanic forces in the fatigued state. These results suggest that despite reduction in exercise performance, reduced muscle glycogen does not limit muscle performance or SR function. Ph. D.

Fatigue and skeletal muscle weakness are problems associated with congestive heart failure. Research does not support the theory that the affected cardiac function is responsible for the fatigue. During skeletal muscle fatigue, calcium handling is altered. Thus, the fatigue associated with congestive heart failure could be attributed to altered calcium handling. The main proteins involved in calcium release are the ryanodine receptor (RyR) and the dihydropyridine receptor (DHPR). The main proteins involved in calcium uptake are the fast and slow isoforms of sarco(endo)plasmic reticulum calcium ATPase (SERCA 1 and SERCA 2 respectively). Calsequestrin (Csq) and calmodulin (CaM) play regulatory roles in calcium handling. Changes in the levels of these proteins could explain alterations in calcium handling and subsequent muscle function. The purpose of this study was to use a genetic model of heart failure, the SHHF rat, to examine the levels of regulatory calcium handling proteins to determine if changes in the amounts of RyR, DHPR, SERCA1, SERCA2, Csq and CaM are altered in congestive heart failure. A significant decrease was found in the amounts of RyR, DHPR, and SERCA 1 of the SHHF gastrocnemius and diaphragm samples in comparison to the control. There was no significant difference found in the amounts of CaM or SERCA 2 between the two groups. Csq was not found to be statistically different between the two groups of the gastrocnemius samples. However, there was an increase in Csq in the SHHF diaphragm samples in comparison to the control. In conclusion, the calcium handling proteins are affected in the genetic model of heart failure. These changes could explain previous reports of altered calcium handling within the skeletal muscles of congestive heart failure animals. Master of Science

This study examined the effects of a sports drink on the performance of young soccer players. Ten competitive young male soccer players, ages 10 and 11, performed two experimental trials while consuming 32 ounces of either a sports drink (G)- Gatorade or a placebo (P)- Crystal Light in a double-blind, crossover design. Both trials consisted of a 15-minute warm-up period, a pre and post exercise test protocol and a 40-minute indoor scrimmage with a five-minute half time. The assigned fluid was consumed just prior to the warm-up, pre-test protocol, scrimmage and post-test protocol as well as during the half time of the scrimmage. The exercise tests included six activities such as shooting velocity, dribbling, passing, jumping, backward running, and sprinting in order to measure skill, agility, power, and speed. The results showed that due to the interaction of the 40-minute scrimmage and the consumption of Gatorade, the post-test shot velocity measurement was significantly (p

Fully differentiated muscle fibers can undergo considerable phenotypic changes in order to adjust to changing conditions of the physiological environment. It is generally accepted that the electrical impulses a muscle receives play a role in modulating the quantities of metabolic proteins (glycolytic and oxidative enzymes) and types of contractile proteins (myosin heavy chain, MHC) that are expressed. Research has shown that decreased neuromuscular activation following spinal cord transection (ST) results in adaptations in the physiological characteristics of paralyzed muscles, including atrophy and an accompanying loss of force production, and transformations of contractile and metabolic proteins toward a more fatigable state. However, it remains unclear whether or not a strong interdependence of energy metabolism and MHC isoform composition persists. Therefore, the goal of this study was to identify and quantify relative myosin heavy chain (MHC) isoform expression and metabolic enzyme profile adaptations at multiple time points (1, 3 and 6 months) in soleus fibers of rats following spinal cord transection (ST). To accomplish this, female Sprague-Dawley rats (~150 g, n = 15) were subjected to complete transection of the spinal cord at a mid-thoracic level. Age and weight-matched, non-operated rats served as controls (n = 15). The soleus was processed for quantitative single fiber histochemical analyses for succinate dehydrogenase (SDH, oxidative marker) and a-glycerophosphate dehydrogenase (GPD, glycolytic marker) activities (~30 fibers/muscle) and immunohistochemical analysis for MHC isoform composition. The total number of soleus fibers analyzed was ~900. Oxidative capacity was increased in muscle fibers at all time points after ST. Specifically, SDH activity was significantly higher than controls by 142, 127 and 206% at 1, 3 and 6 months post-ST, respectively. ISDH, a measure of total oxidative power, also increased in muscle fibers at all time points after ST. For example, 6 months after ST ISDH activity was 93% higher than controls (91.8-3.8 vs. 47.6-0.9 OD x 10-3, respectively). Glycolytic capacity peaked one month after ST. Thereafter, glycolytic capacity of all fibers steadily declined. For example, by 6 months, GPD activity had declined by 76% compared to 1 month GPD activities (3.3-0.2 vs. 13.7-1.4 OD x 10-3, respectively). These data suggest that the increases in glycolytic capacity are transient as fibers transition toward a faster MHC phenotype and then return towards control levels as fibers of a given type become phenotypically stable. The GPD/SDH ratio, an index of metabolic substrate utilization, peaked at one month after ST (394-41) and significantly decreased at 3 months (224-10) and at 6 months (95-7) after ST. Therefore, a shift occurred such that a greater dependence on oxidative metabolism was apparent. These data suggest that the oxidative capacities of soleus muscle fibers are not compromised after ST. In fact, as the fibers transitioned toward faster MHC isoforms, the GPD/SDH ratio was maintained or decreased, suggesting a reliance on oxidative metabolism regardless of MHC isoform composition. This might imply a dissociation between the contractile and metabolic characteristics of paralyzed soleus muscle fibers. However, these data are consistent with previous data and suggest that the increased fatigability observed after chronic reductions in neuromuscular activity are not due to compromised capacities for ATP synthesis. Master of Science

Skeletal muscle fatigue can be defined as the inability to produce a desired amount of force. Fatigue can not only limit athletic performance and rehabilitation, but it can affect one's ability to perform every day activity as well. Despite extensive investigation of muscle fatigue, little is known about the exact mechanisms that result in decreased muscle performance. It likely involves several factors that are themselves dependent upon activation patterns and intensity. The process of excitation-contraction (EC) coupling is of particular importance with respect to regulation of force production. The release of calcium (Ca²⁺) from the sarcoplasmic reticulum (SR), which is stimulated by the depolarization of the sarcolemma, causes muscle contraction. The SR Ca²⁺-adenosine triphosphatase (ATPase) drives the translocation of two Ca²⁺ ions into the SR, utilizing the energy derived from the hydrolysis of one adenosine triphosphate (ATP) molecule. The process of SR Ca²⁺ uptake causes muscle relaxation. It has been proposed that both glycogen and glycolytic enzymes are associated with the SR membrane (SR-glycogenolytic complex). Interestingly, glycogen phosphorylase, an enzyme involved in glycogen breakdown, seems to be associated with the SR-glycogenolytic complex through its binding to glycogen. The presence of the SR-glycogenolytic system may serve to locally regenerate ATP utilized by the SR Ca²⁺-ATPase. The purpose of the present study was to investigate the effects of prolonged muscle contraction on glycogen concentration, glycogen phosphorylase content and activity, and maximum Ca²⁺ uptake rate associated with the SR. Tetanic contractions, elicited once per second for 15 minutes, significantly reduced glycogen associated with SR to 5.1% of control from 401.17 ± 79.81 to 20.46 ± 2.16 mg/mg SR protein (£ 0.05). The optical density of glycogen phosphorylase from SDS-PAGE was significantly reduced to 21.2% of control (£ 0.05). Activity of glycogen phosphorylase, in the direction of glycogen breakdown, was significantly reduced to 4.1% of control (£ 0.05). Pyridoxal 5'-phosphate (PLP) concentration, a quantitative indicator of glycogen phosphorylase content, was significantly reduced to 3.3% of control (£ 0.05). Maximum SR Ca²⁺ uptake rates were significantly reduced to 80.8% of control (£ 0.05). These data suggest reduced glycogen and glycogen phosphorylase may be involved, either directly or indirectly, in a mechanism that causes decreased SR Ca²⁺ uptake normally found in fatigue. Master of Science

Numerous references have suggested that alterations in exercise capacity during congestive heart failure (CHF) are not simply due to changes in myocardial function. In fact, recent evidence has indicated that reductions in skeletal muscle strength and endurance during CHF significantly impact exercise capacity of the CHF patient. Currently, it is believed that alterations in skeletal muscle phenotype, or more specifically a slow to fast transformation in phenotypic protein isoforms contribute to the reductions in muscle function. However, currently there are few data which directly document this slow to fast transformation of the skeletal muscle. Interestingly, it is well established that exercise training can cause changes in skeletal muscle phenotype, more specifically in the fast to slow direction. This is in direct contrast to what is known to occur during CHF. However, it is unclear if similar adaptations will result from training in a CHF patient. Also, it is not clear if the adaptations are due to alterations in the myocardium or changes directly imposed upon the muscle by the exercise training. Therefore, the purpose of this study was two-fold: 1) to clarify the changes in skeletal muscle myosin heavy chain (MHC) during CHF and 2) to determine if skeletal muscle can adapt to increased activity levels, utilizing functional overload (FO) without significantly improving cardiac function. In the first study the mixed plantaris muscles from rats afflicted with severe CHF demonstrated a significant (p

Eight competitive cyclists performed two cycling trials, one following a high carbohydrate diet (H-CHO) and the other following a low carbohydrate diet (L-CHO). Trials consisted of repeated 60s maximal effort sprints to fatigue at a workload designed to elicit 125-135% VO2peak at 90rpm. Three min of recovery separated sprints. Muscle biopsies taken at rest (biopsy 1), 85% max interval rpm (biopsy 2), and 70% max interval rpm (biopsy 3) revealed a main effect of diet on muscle glycogen levels: 609 ± 38 HCHO vs. 390 ± 42 mmol/kgdw L-CHO at biopsy 1, 383 ± 29 vs. 252 ± 28 mmol/kgdw at biopsy 2, and 346 ± 29 vs. 196 ± 18 mmol/kgdw at biopsy 3 (p

The existence of a glycogen-sarcoplasmic reticulum has been demonstrated by a number of researchers. This complex is suspected to participate in the calcium uptake activities of the sarcoplasmic reticulum (SR). Removal of glycogen particles associated with this complex may alter the calcium handling abilities of the SR. This experiment sought to determine what effect exercise and treatment with a-amylase had on the abilities of the SR to regulate intracellular calcium ([Ca2+]i). Rats were either run on a treadmill for 60 min at a speed of 21 m/min and a 10% grade or were not exercised. Animals were then killed by decapitation after inhalation of CO2. Left and right gastrocnemius muscles were excised from both groups and underwent SR vesicle preparation to separate the heavy and light SR fractions (HSR and LSR respectively). Left hindlimb muscle homogenate also underwent 60 min incubation with a-amylase to digest glycogen before differential centrifugation. Treatment with a-amylase significantly depressed rate of calcium uptake by LSR and HSR fractions by 22.89% and 25.22% respectively (p

Stress fractures are common overuse injuries that have plagued athletes for many years. Often referred to as fatigue fractures, they are formed when the skeletal muscles fatigue and can no longer absorb the shock of repetitive pounding activities such as running. Stress fractures are most common in the weight-bearing bones of the lower extremities and are usually preceded by sudden increases or changes in training routines. Because they are most common in athletes who are least fit, it has been hypothesized that freshmen athletes who are not prepared for the increased physical demands of college athletics have the greatest risk for developing stress fractures compared to other academic classes. As of yet however, there have been very few studies that have examined the interaction of different variables such as academic class, on the formation of stress fractures. Therefore, the purpose of this study was to look at the incidence, frequency and pattern of stress fractures among the female athletes at Virginia Polytechnic Institute and State University. A retrospective analysis of 28 injury cases over four years revealed that 67% of the injuries occurred in freshmen athletes. The majority of these were in the lower leg and occurred in mid-season rather than pre-season. There were no relationships found between the variables sport, class, site and season and thus it was concluded that the incidence of injury was not affected by the interaction of these variables. However, the variables themselves did influence the formation of stress fractures. Ultimately, this study provided insight on what factors should be carefully examined in order to prevent future stress fracture injuries in collegiate athletes. Master of Science

Restricting dietary protein may reduce endogenous acid load. Horses were fed diets with 10% supplemental corn oil in experiment one and either 0% or 10% supplemental corn oil in experiment two. Also, low protein (7.5% crude protein, LP) fortified with .5% lysine and .3% threonine or high protein (14.5% crude protein, HP) was fed. Horses underwent similar interval training and standard exercise tests. In experiment two, horses performed an SET prior to conditioning. The SET consisted of warm ups at the walk and trot followed by six repeated sprints and concluding with a 30 minute recovery at the walk. All sprints were at 10 m/s except the SET prior to conditioning in experiment two, which were at 7 m/s. Blood samples were taken every two weeks and as part of SETs. Samples were analyzed for pH, pCO₂, pO2, Na⁺, K⁺, Cl⁻, lactate, total protein (TP), albumin, creatinine and plasma urea-N (PUN). Bicarbonate, strong ion difference (SID) and total weak acids (Atot) were calculated. Plasma urea-N concentrations were higher in the HP group. Plasma creatinine was not different in experiment one but was higher in the LPHF group in experiment two. Also, the LPHF group had a low body condition score and the same weight therefore had a higher lean body mass. Plasma albumin was not different in either experiment and TP was not different in experiment one. Total protein was higher in the HF groups in experiment two. Protein moderated acid-base responses to SETs in both experiments. The LP group had higher pH and bicarbonate levels as well as a tendency for a higher SID in experiment one and in the SET prior to conditioning for experiment two. Lower lactate levels were observed in the LP group in experiment one. Following conditioning in experiment two, the LP group had higher pH and bicarbonate levels but only combined with HF. Restricting dietary protein can increase pH and bicarbonate levels and high fat has been shown to improve fatty acid oxidation and spare muscle glycogen. Therefore, restricting dietary protein especially in combination with high fat may be beneficial for the exercising horse. Ph. D.

This study examined effects of carbohydrate (C), carbohydrate-protein (CP), or placebo (P) beverages following eccentric resistance exercise on muscle damage by serum creatine kinase (CK), muscle protein breakdown by urinary 3-methylhistidine (3MH), muscle soreness, isokinetic muscle strength, muscle glycogen resynthesis, and serum hormones. Untrained males (N=26) underwent a 9-day controlled meat-free diet and 24 hr urine collections. To reduce glycogen, subjects cycled for 40 min at 70% of VO2peak followed by 5 cycling sprints on day 4 evening. On day 5, fasted subjects performed 100 eccentric leg flexions at 120% of 1-RM and drank C (n=8, 1.25 g C/kg), CP (n=9, 0.875 g C/kg, 0.375 g protein/kg), or P (n=9) beverages immediate post-exercise (IPE) and 2 hr later. Muscle biopsies were taken IPE on day 5, and days 6 and 8 mornings. Blood was obtained days 4-10 fasted plus IPE, 3 hr, and 6 hr post-exercise on day 5. At 3 hr on day 5, insulin was higher for CP (24.6 ( 15.5 µIU/ml) and C (17.2 +/- 10.9 µIU/ml) than P (5.3 +/- 0.4 µIU/ml, po/s decreased 24% on day 6 and remained depressed by 21% on d 8 (p

The purpose of this investigation was to determine the effects of a four day creatine load and simultaneous energy restriction on muscle creatine content, exercise performance, and body composition in 24 male recreational resistance trainers, age 18-26. Sixteen subjects were randomly divided into placebo (Pl, n=8) and creatine supplement (CrS, n=8) groups. Control (C, n=8) subjects of the same age were recruited separately g à d-1 to complete the performance and body composition tests while consuming their normal diet. The CrS group was administered 20 g à d-1 of creatine monohydrate (Cr) mixed with 5 g à d-1 of sucrose, while the Pl group was administered 25 of sucrose. Both CrS and Pl consumed a formula diet of 75.3 kJ (18 kcal) à kg-1 à d-1 for 4 d. Testing before and after energy restriction consisted of a repeated sprint cycle performance test (10 sprints of 6s, with 30s rest), hydrostatic weighing, and resting needle muscle biopsy. Testing revealed that subjects in CrS and Pl demonstrated significant decreases in body weight and % body fat (%BF) with no difference between groups. However, Pl demonstrated a significantly greater % loss in FFM (2.4 ± 0.25%) compared to CrS (1.4 ± 0.4%) (p

The role of glycogen in endurance performance has been accepted in theory. It has been shown that higher resting muscle glycogen levels prolong endurance performance. On the other hand, low glycogen levels have been associated with fatigue. Ultimately, a person's muscle glycogen level dictates the duration in which an activity can be maintained at a maximal effort, after which time, performance will decrease. As of yet, there has been no evidence as to what happens to the fatigued muscle. Force production in skeletal muscle is dictated by the release and uptake of Ca²⁺ from the sarcoplasmic reticulum (SR). Force production is proportional to [Ca²⁺], as [Ca²⁺] increases so does force. At the point of fatigue, there is a decrease in force production. Since fatigue has been associated with glycogen depletion, it is likely that SR function has been altered causing this decrease in force. The purpose of this study was to determine the effect of glycogen depletion on the SR. Twenty male Sprague-Dawley (Harlan Sprague-Dawley, Indianapolis, IN) rats weighing, 345 ± 70 gm were housed two per cage in the Virginia Tech Lab Animal Resources facility. They were fed ad libitum (Purina Rodent Laboratory Chow and water) until time of experiment. Ten of the rats were used as control animals and the other ten were assigned to the experimental group. Rats were allowed a minimum of 5 days to acclimate to their housing. On the morning of the day of testing, rats were selected in pairs according to the housing cage in an effort to decrease variations in food consumption. To reduce muscle glycogen levels, experimental rats were given an initial injection of either epinephrine (1mg/g: ip) while control rats were injected with saline (equal volume) at 0 hr. Thirty minutes later they received another injection of epinephrine or saline (0.5 mg/g: ip). At the end of the hour the rats were anesthetized with pentobarbital sodium (60 mg/kg:ip) for tissue harvesting. Upon reaching a surgical plane of anesthesia one gastrocnemious muscle was extracted for the muscle glycogen assay and the other removed for SR vesicle preparation. Rats were then euthanized with an overdose of pentobarbital sodium. The tissue was assayed for glycogen and glucose levels as well as for Ca²⁺ uptake and release and ATPase activity. It was found that epinephrine animals had 23% less glycogen than did the control animals and almost twice the amount of glucose (control — 2.9 nmol/g and epinephrine — 5.9 nmol/g). Ca²⁺ uptake rates in epinephrine animals were significantly decreased by 19.7% (p < .05). Control animals had a release rate of 77.15 ± 1.26 nmol/mg/min and epinephrine animals had a release rate of 75.01 ± 1.86 nmol/mg/min. Ca²⁺ release rates were decreased but not significantly. Ca²⁺ stimulated ATPase activity was significantly decreased by 17.7% in epinephrine animals (p < .05). This is one of the first studies that demonstrate that glycogen reduction in a rested muscle causes altered SR function similar to those caused by exercise. This study shows that low glycogen levels are associated with decreased SR function, which is the primary reason for causing the loss of force in muscle. Ultimately, this study suggests that glycogen loading will enhance endurance performance. Master of Science

The production of reactive oxygen species (ROS) may be a contributor to the progression of sarcopenia. Sarcopenia is a generic term for the loss of skeletal muscle mass, quality and strength. ROS are usually produced by radiation, but are also the byproducts of aerobic metabolism. ROS have been found to mediate various pathological conditions in a variety of tissues, to cause oxidative damage to DNA, proteins, and lipids with advancing age, and is presumably a major factor contributing to changes associated with aging. The purpose of this investigation was to determine whether the sarcoplasmic reticulum (SR) of muscle from aged animals are more susceptible to the deleterious effects of ROS. Using isolated gastrocnemius SR vesicles extracted from adult (12m) and aged (27m) male Brown Norway-Fischer 344 hybrid rats, Ca2+ uptake and release measurements were obtained. The data showed that there was a 33% difference between aged and adult gastrocnemius mass. When gastrocnemius mass was corrected for body mass, the differences was ~20% between the two groups. A 20% decrease in SR Ca2+ uptake rate was noted in aged animals. HOCl also, decreased uptake by similar extents in both groups. This result suggest that the Ca2+ pump's response to ROS are similar in both groups. AgNO3 -induced and H2O2 -induced release in aged animals was 17.94 and 7.39 nmol/mg/min and in adult animals was 30.46 and 7.18 nmol/mg/min, respectively. H2O2-induced release, when expressed as a percent of AgNO3-induced release was increased in aged animals by 54%. The results suggest that the release channel of aged muscle appears to be more sensitive to ROS. In conclusion, the data support the theory that aged animal skeletal muscle is more susceptible to the adverse effects of ROS. Master of Science

The decline of physical ability that occurs with aging has been linked to reduced skeletal muscle function. It has been theorized that Ca2+ uptake and release by the sarcoplasmic reticulum (SR) is altered with aging. Data pertaining to the actual structural and functional changes of SR due to aging are limited; thus, this theory has not yet been fully proven. The purpose of this research was to determine if SR function is altered as a result of aging in the following muscles: soleus, plantaris, and diaphragm. The soleus is composed of slow twitch muscle fibers. The plantaris is composed of fast twitch muscle fibers, and the diaphragm is composed of both slow and fast twitch muscle fibers. Fisher 344 Brown x Norway Cross Rats were used as subjects for this project. A total of 12 animals were used: six in group 12 months and six in group 27 months. A Jasco CAF-110 Fluorometer and fura-2 were used to determine the rate of Ca2+ uptake and release by isolated SR vesicles. In the aged animals, mass of the soleus was reduced by 22%, while the plantaris was reduced by 23%, and the diaphragm by 15%. However, these differences were eliminated when masses were normalized by body mass. In all three muscles examined, the rates of Ca2+ uptake were not significantly different between the young and aged animals. Rates of Ca2+ release, however, were reduced by 30% in both the plantaris and diaphragm of the aged animals. These results suggest that SR function is altered in "fast" muscles of the rat. It is possible that changes in SR Ca release may contribute to diminished muscle function and also lead to the decline in physical ability of older adults. Master of Science

Overtraining is a common problem in athletes that prevents many from becoming "elite". A decrement in an athlete's performance is usually an indicator that overtraining syndrome may be developing. Unfortunately, there is no model that can determine overtraining. A decline in performance results in a depression in maximum muscular force. It is not known whether the force depression is a result of central or peripheral factors. In this study, the two training protocols on different legs determined whether force declines are muscular (peripheral) or psychological (central). Specifically, in this study, the subjects trained one leg at maximal intensity for two weeks, and the other trained at a low intensity for two weeks. After training for two weeks, both legs were placed on a low intensity workout to monitor the recovery process. The purpose of this study was to observe muscle strength performance decrements after overtraining one leg in comparison to properly training the other leg by knee extension exercises for two weeks in trained males. Also, after overtraining the one leg for two weeks, the leg was placed on a reduced training program in order to look at recovery if overtraining occurred. Maximal force output was measured isokinetically on the Biodex three times: pre-, post-, and final test. An analysis of this data revealed no significant changes in maximal muscular force output after a high intensity training protocol. Therefore, this investigation demonstrated that overtraining in the quadricep did not result from the two weeks of high intensity resistance training. Master of Science

The essential amino acid tryptophan serves as the precursor to serotonin, a neurotransmitter which regulates hunger and satiety, promotes sleep, relieves depression, and is found in elevated levels following exercise. A quantitative deficit in serotonin or abnormality in its mode of action is thought to be one cause behind several psychological disorders such as depression, eating disorders, and obsessive-compulsive disorder. A decrease in dietary tryptophan has been shown to decrease serotonin production thereby, theoretically, producing the effects of a hyposerotonergic state. The purpose of this study was to further elucidate serotonin’s role in influencing an individual’s activity level by inducing a decrease in this neurotransmitter via a tryptophan-depleted diet. Specifically, 40 individually-housed mice were divided into four groups of ten. Group C received a control diet while group CW consumed a control diet and had access to a running wheel. Group E received a diet low in tryptophan while group EW was given the experimental diet and had access to a running wheel. A seven-day adaptation period was followed by a ten-day experimental period during which time groups E and EW received the experimental diet. Only the food consumption of group EW increased significantly over time. Running wheel activity was monitored every 12 hours corresponding to a light/dark cycle. An analysis of this data revealed a significant post-test rise in the activity levels of the mice in group EW compared to the activity of group CW. The wheel revolutions per 24 hours dropped by 17% in group CW while group EW’s revolutions increased by 19%. Furthermore, while revolutions increased from pre-test to post-test in only four out of 10 control subjects, they increased in all nine of the experimental subjects. It seems likely that the tryptophan depletion caused a decrease in brain serotonin levels. Therefore, the results of this experiment support the theory that the mice on a low-tryptophan diet increased their activity in a subconscious effort to normalize serotonin levels which would bring about a return of the desirable effects of this neurotransmitter. Master of Science

This study examined the effects of six weeks of velocity specific isokinetic training on peak torque (PT), and the estimated cross-sectional area of the upper arm (AG) in the trained. Thirty volunteers (M=15, F=15) were randomly assigned to an experimental, slow velocity group (S), 60 degrees-per-second (n=9; 25.4±..6.5yr), a fast velocity group (F), 450 degrees-per-second (n=ll, 23.7 ±..S.4yr), or control group (C) (n=10, 26 ± 3.2yr). One limb was randomly selected for isokinetic training (3 d/wk-elbow flexion) using a Biodex System 2 isokinetic dynamometer. The contralateral limb served as a control and as the basis for measurements measure of cross education (CE). Both experimental conditions (S) and (F) were assigned equal training workloads, calcu1ated from an isokinetic pre-test. Pre- and post-tests (PT) were recorded for both limbs at the training velocities of 60 and 450 degrees-per-second, as well as the velocity of 210 degrees-per-second. Pre and post-test (AG's) were measured on the training limb. The (S) condition was significantly different in strength gains from the control at 60 degrees-per-second, but not different from the fast velocity group in the trained limb. The (F) condition was significantly different in strength gains from the control at 450 degrees-per-second, but not different from the slow velocity group in the the trained limb. The conditions were not significantly different from each other in the trained limb at the test velocity of 210 degrees-per-second. The three conditions significantly different from each at the test velocity of 60 degrees-per-second in the trained limb. The conditions did not differ in strength at velocities of 210 and 450 degrees-per-second in the trained limb. The conditions did not differ in the cross-sectional area of the upper arm in the trained limb. The (S) and (F) training conditions improved (PT) by 12.36% and 18.84% at their respective training velocities of 60 and 450 degrees-per-second. These improvements were significantly (p

Force regulation at the level of the actin-myosin cross-bridge (XB) can be described by a 2 state model in which the XB's cycle between a strongly bound (SB), force generating state and a weakly bound (WB), non-force generating state. This cycle can be characterized by the apparent rate constants for transition into the SB state (fapp) and returning to the WB state (gapp), Increases in XB force can be accounted for by an increase in fapp a decrease in gapp., or both. While effort towards understanding XB force regulation has focused on the notion that force production is primarily regulated by fapp the purpose of this investigation was to determine if gapp continues to force regulation at the XB and to determine whether gapp differs in,muscles with differing contractile characteristics. Ph. D.

Although previous investigations have reported performance benefits following the administration of sodium bicarbonate, evidence of its influence on upper-body activity is limited. Master of Science