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This is an open access article under CC BY license (https://creativecommons.org/licenses/by/4.0/) Background: Effects of internal and external workloads (IL, EL) on lower limb soft-tissue injuries (LLSTI) risk in male soccer players has been described, the relationships remain unclear in collegiate female (soccer players. Objective: The purpose was to examine the mean difference in IL and EL in LLSTI between non-injured and injured groups (N-IG and IG). Method: 20 collegiate female soccer players (age: 19.2±1.2years; height: 168.2±7.3cm; body mass: 41.0±17.9kg) were included for 14 week competitive season. IL included average heart rate (Avg-HR) and high heart rate zone. EL included total distance, average speed (Avg-Spd), and high-speed running distance. Injuries were counted if (a) they were LLSTI and muscular/ ligamentous strains or tears and tendon problems, and (b) the players missed more than one match or training session. Acute (7-day simple average) and chronic (21-day simple average) IL and EL were calculated in the IG while the mean of acute (7-day) and chronic (21-day) IL and EL were computed in the NIG. Acute Chronic Workload Ratio (ACWR) was calculated as the ratio of acute and chronic IL and EL. Results: Seven LLSTI occurred over 14 weeks. The acute Avg-HR and ACWR of Avg-Spd were significantly higher in the IG than the N-IG (p=0.001 and 0.024). IL and EL in the IG were placed below or above the mean of the N-IG. Conclusion: LLSTI might occur at high and low workloads in collegiate female soccer players. This may support the use of micro-technology to monitor workload based on individual player’s threshold to reduce LLSTI.

Dietary protein is required to support recovery and adaptation following exercise training. While prior research demonstrates that many athletes meet total daily protein needs, intake seems to be predominantly skewed toward the evening meal. An even distribution of protein doses throughout the course of a day is theorized to confer greater skeletal muscle anabolism compared to a skewed pattern of intake. Protein quality is also an important dietary consideration for athletes, with the amino acid leucine being the primary driver of the postprandial anabolic response. The present thesis investigates the protein consumption characteristics among a selected cohort of NCAA Division 1 collegiate soccer players and evaluates differences between male and female athletes. Athletes were instructed to complete 3-day food diaries, which were subsequently analyzed and compared to nutrition guidelines for soccer players. Breakfast, lunch, and dinner explained 81.4% of total daily dietary protein intake. Most athletes (77.8%) ingested optimum amounts of protein at dinner, but not at breakfast (11.1%) or lunch (47.2%). In addition, statistically significant sex-based differences in daily dietary protein intake, meal-specific protein amounts, and protein quality measures were detected. Findings indicate suboptimal dietary protein intake practices among the collegiate athletes.

Over 270 million people play soccer worldwide, and its popularity grows every day. In team sport exercise, fatigue may result from numerous factors including limited fuel, depleted energy stores and production of compounds that promote an inflammatory response. While inflammation is an essential mechanism for repairing damaged muscle tissue with exercise, prolonged inflammation leads to increased production of reactive oxygen species that can damage cell membranes, muscle, and signaling proteins. To prevent this response and improve performance, athletes are increasingly looking to nutritional interventions. Carbohydrate and antioxidant supplementation have both shown evidence of producing an ergogenic effect and attenuating inflammation and oxidative stress with prolonged endurance exercise. Less is known about how these interventions may influence intermittent, high-intensity exercise characteristic of soccer. In particular, this exercise presents a unique challenge in that opportunities for nutrient intake are limited to pre-game and half-time. In our first study, we had 10 male collegiate soccer players perform a 90-min. soccer-simulation test, that we developed, which was followed by a progressive shuttle run (PSR) test to exhaustion. They consumed a honey-sweetened beverage (H), a sports drink (S), or a placebo (P) before and half-way through the protocol. Both H and S provided 1.0 g·kg⁻¹ carbohydrate and ~17.6 mL·kg⁻¹ total volume for each trial. Overall, the test resulted in increased fatigue and production of inflammatory markers and antioxidant capacity. There was no significant difference between treatments for any performance measure. Mean times for a high intensity run and rating of perceived exertion increased with time, and there was an overall decrease in PSR time compared to baseline (-22.9%). There was a rise in glucose (15.6%), IL-6 (548%), IL-1ra, IL-10 (514%) and ORAC (15%) post-test but no change in cortisol. Insulin was significantly lower by 1 h-post. IL-1ra levels increased post-test for H (25.8%), S (65.5%), and P (63.9%), but the change for H was less than the other treatments. No treatment effects for the other blood measures were observed. The lack of an ergogenic effect of carbohydrate on soccer performance calls into question the benefit of supplementation at a frequency typical of a regulation soccer match in highly trained athletes with adequate energy stores. Since acute carbohydrate ingestion in the first study did not attenuate some markers of inflammation (e.g. IL-6), we chose to focus on an alternative theory for the rise in inflammatory markers with strenuous exercise in our second study. One aspect of soccer, repeated sprinting, results in increased ROS production partially through the activation of the enzyme xanthine oxidase (XO). Quercetin, a flavonol in plants that has shown some ergogenic effects with endurance exercise, inhibits XO in vitro. The effect of quercetin on team sport exercise had not been studied. We gave recreationally active males a commercial sports drink (S) or S + 500 mg of quercetin (Q) 2x/d for 1 wk prior to a repeated sprint test (RST). Sprint times increased (5.9%) for both treatments as did plasma XO activity (47%), IL-6 (77%), and uric acid (25%) from pre-test to post-test. Q supplementation did not attenuate plasma XO activity or IL-6 and actually increased one calculated index of fatigue, percent fatigue decrement (5.1%- Q and 3.8%- P). These findings add to the growing body of literature that quercetin supplementation does not attenuate exercise-induced inflammation and oxidative stress in vivo. Collectively, this research has practical implications for sports drink companies who are exploring the use of flavonoid compounds in product formulation. Specifically, they should reconsider adding quercetin to their beverages if they are marketing to team sport athletes. Also, soccer players should be made aware that, at ingestion frequencies typical of a soccer match, they may not expect a significant performance benefit from acute carbohydrate supplementation. / Ph. D.

The purpose of this study was to examine the prevalence and potential abnormalities of biomarkers in female soccer and field hockey players by conducting a meta-analysis of previous studies. In this study, previous research on certain biomarkers (Creatine kinase, lactic acid, iron, hemoglobin, white blood cells, and cortisol) in collegiate, elite and national level female soccer and field hockey players was collected and evaluated. Studies on baseline measurements for these biomarkers in female soccer and field hockey athletes were collected and their group means were considered. These values were collectively put into individual forest plots, one for each biomarker, and were thereafter compared to a given normal laboratory blood value range for the general population. Whereas iron, white blood cell count and especially hemoglobin tended to lie either towards or beneath the lower limit of the reference range assigned to the general population, CK and cortisol have a tendency to be higher in athletes compared to the general population. The findings for lactic acid did not have a significant tendency in either direction. The findings made throughout this study indicate the importance of proper nutrition for the athletes. Furthermore, the findings reiterate and remind coaches and health professionals of the importance on not only the education on proper nutrition for athletes, including sufficient iron intake and possible iron and vitamin supplementation but also the importance of adequate rest and time for recovery to limit the risk of overtraining and high intensity exercise related illness and infection.

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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.

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.