Athlete’s Social Capital Influences and Feelings of Team Cohesion

Faculty Mentor: Dr. Joseph Merr

Athlete’s Social Capital Influences and Feelings of Team Cohesion

Faculty Mentor: Dr. Joseph Merr

METABOLIC EFFECTS OF HIGH-INTENSITY INTERVAL TRAINING AND ESSENTIAL AMINO ACID SUPPLEMENTATION

High-intensity interval training (HIIT) promotes rapid mitochondrial adaptation leading to increased cardiorespiratory fitness (VO2), metabolic rate (RMR), and fat oxidation, in addition to promoting fat loss and increases in lean mass (LM). Nutritional intake around exercise is also known to modulate metabolic responses during and after exercise, which is further influence by sex. Essential amino acids (EAA) may support positive body composition and metabolic changes associated with HIIT, especially related to LM, but studies evaluating potential synergistic effects are lacking. The purpose of this study was to compare independent and combined effects of HIIT and EAA on body composition, muscle characteristics, and total body metabolism in overweight and obese adults; an exploratory aim was to evaluate the modulatory effects of sex. Sixty-six adults (50% female; Age: 36.7±6.0 yrs; %BF: 36.0±7.8%) were randomly assigned to 8wks of: 1) HIIT (2 days/week); 2) EAA supplementation (3.6g twice daily); 3) HIIT+EAA; or 4) control. Body composition, RMR, substrate metabolism, VO2, and muscle characteristics were measured at baseline, 4wks, and 8wks; whole-body protein turnover and cardiometabolic blood markers were measured at baseline and 8wks. Results showed no significant changes in body composition (p>0.05). HIIT and EAA separately promoted increases in RMR (HIIT: +78.40 kcal/d) and fat oxidation (HIIT: +13%; EAA: +10%). HIIT and HIIT+EAA significantly increased VO2, with an average increase of +5.1 ml/kg/min and +4.1 ml/kg/min after 8wks of HIIT and HIIT+EAA, respectively. HIIT and HIIT+EAA increased thigh LM size and quality, as indicated by increases in thigh LM (+0.2 kg) and vastus lateralis cross sectional area (+2.6 cm2), volume (+58.45 cm3), and echo intensity (-6.75 a.u.); improvements appeared to be enhanced by EAA supplementation, via an increase in whole-body protein turnover (+1.0 g/kgBM/d). There were no significant changes in cardiometabolic markers (p>0.05). There was no sex interaction, indicating similar benefits in men and women. In conclusion, 8wks of HIIT, with and without EAA, did not improve total body composition, but increased thigh LM size and quality, while also promoting positive improvements in RMR, fat oxidation, and VO2 in overweight and obese men and women.Doctor of Philosoph

METABOLIC CHARACTERIZATION OF OVERWEIGHT AND OBESE ADULTS

Obesity is associated with diseases such as metabolic syndrome, but not all obese individuals have traditional markers of dysfunction like insulin resistance and dyslipidemia. To characterize metabolic health in 49 overweight and obese adults, body composition (fat mass [FM], lean mass [LM], percent body fat [%fat]), was calculated using a 4-compartment model; visceral adipose tissue (VAT) was quantified using B-mode ultrasound. Resting metabolic rate (RMR), respiratory exchange ratio (at rest and during exercise), fasting lipids, insulin, and leptin were also analyzed. Fat mass, %fat, and VAT correlated with insulin and leptin (r=0.369-0.829; p0.05). Higher RMR was associated with LM (r=0.900, p<0.001). When evaluating body composition and metabolism in addition to traditional metabolic syndrome criteria, individuals with disease risk increased from 29% to 80%. Lean mass, VAT, RMR, and hormones may be indicators of metabolic dysfunction in the absence of traditional risk factors.Master of Art

Body Composition and Muscle Characteristics of Division I Track and Field Athletes

The purpose of this study was to evaluate event-specific body composition and muscle characteristics of track and field athletes, and to assess body composition changes after one year. Sixty collegiate track and field athletes (Mean ± SD; Age = 19.2 ± 1.4 yrs, Height = 174.6 ± 9.0 cm, Weight = 71.5 ± 12.5 kg) were stratified into six event groups. Total and regional body composition measurements were assessed using dual-energy x-ray absorptiometry. A panoramic scan of the vastus lateralis was taken with B-mode ultrasound to determine muscle cross sectional area (mCSA) and echo intensity (EI). Body composition measurements were repeated a year later in a subset of returning athletes (n=33). Throwers had significantly more absolute fat mass (FM; 21.6 ± 11.0 kg), total body mass (89.7 ± 17.4 kg), percent fat (23.6 ± 7.8) and trunk fat (9.4 ± 5.8 kg) than all other event groups (p0.05), but relative to body mass had relatively less LM (0.72 ± 0.08 kg; p<0.05). Despite high FM, throwers had lower EI (63.4 ± 5.2 a.u). After one year, relative armLM increased slightly in all event groups (p<0.05). Evaluation of muscle characteristics in addition to total and regional body composition may be valuable for improving performance, injury prevention, and assessing health risks. With appropriate training, track and field athletes may be able to minimize losses in LM and gains in FM between seasons

Seasonal Effects on Body Composition, Muscle Characteristics, and Performance of Collegiate Swimmers and Divers

Previous researchers have indicated the importance of body composition and muscle quality in athletic performance. However, body composition and muscle-quality measures in swimmers and divers over a training season have yet to be evaluated

Municipal investment in off-road trails and changes in bicycle commuting in Minneapolis, Minnesota over 10 years: a longitudinal repeated cross-sectional study

Abstract Background We studied the effect of key development and expansion of an off-road multipurpose trail system in Minneapolis, Minnesota between 2000 and 2007 to understand whether infrastructure investments are associated with increases in commuting by bicycle. Methods We used repeated measures regression on tract-level (N = 116 tracts) data to examine changes in bicycle commuting between 2000 and 2008–2012. We investigated: 1) trail proximity measured as distance from the trail system and 2) trail potential use measured as the proportion of commuting trips to destinations that might traverse the trail system. All analyses (performed 2015–2016) adjusted for tract-level sociodemographic covariates and contemporaneous cycling infrastructure changes (e.g., bicycle lanes). Results Tracts that were both closer to the new trail system and had a higher proportion of trips to destinations across the trail system experienced greater 10-year increases in commuting by bicycle. Conclusions Proximity to off-road infrastructure and travel patterns are relevant to increased bicycle commuting, an important contributor to overall physical activity. Municipal investment in bicycle facilities, especially off-road trails that connect a city’s population and its employment centers, is likely to lead to increases in commuting by bicycle

Effects of coffee and caffeine anhydrous on strength and sprint performance

Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, ten-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300 mg flat dose; yielding 3–5 mg/kg bodyweight), COF (8.9 g; 303 mg caffeine), or placebo (PLA; 3.8 g noncaloric flavoring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p=0.04), but not PLA (p=0.99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p>0.05). There were no sprint × treatment interactions for PP or TW (p>0.05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise

Longitudinal Body Composition Changes in NCAA Division I College Football Players

Many athletes seek to optimize body composition to fit the physical demands of their sport. American football requires a unique combination of size, speed, and power. The purpose of the current study was to evaluate longitudinal changes in body composition in Division I collegiate football players. For 57 players (Mean ± SD; Age=19.5 ± 0.9 yrs; Height=186.9 ± 5.7 cm; Weight=107.7 ± 19.1 kg), body composition was assessed via dual-energy x-ray absorptiometry in the off-season (March-Pre), end of off-season (May), mid-July (Pre-Season), and the following March (March-Post). Outcome variables included weight, body fat percentage (BF%), fat mass (FM), lean mass (LM), android (AND) and gynoid (GYN) fat, bone mineral content (BMC), and bone density (BMD). For a subset of athletes (n=13 out of 57), changes over a 4-year playing career were evaluated with measurements taken every March. Throughout a single year, favorable changes were observed for BF% (Δ=−1.3 ± 2.5%), LM (Δ=2.8 ± 2.8 kg), GYN (Δ=−1.5 ± 3.0%), BMC (Δ=0.06 ± 0.14 kg), and BMD (Δ=0.015 ± 0.027g·cm−2; all p<0.05). Across four years, weight increased significantly (Δ=6.6 ± 4.1kg), and favorable changes were observed for LM (Δ=4.3 ± 3.0 kg), BMC (Δ=0.18 ± 0.17 kg), and BMD (Δ=0.033 ± 0.039 g·cm−2; all p<0.05). Similar patterns in body composition changes were observed for linemen and non-linemen. Results indicate that well-trained collegiate football players at high levels of competition can achieve favorable changes in body composition, even late in the career, which may confer benefits for performance and injury prevention

Strength and Mobility Measures in Division I Female Volleyball Student Athletes Across Different Positions

Shoulder internal and external rotation and hand grip measures are commonly used to evaluate upper extremity mobility and strength in college athletes. However, positional differences and their impact on these scores are rarely considered, therefore further research is needed in sports such as volleyball where information on these potential trends is lacking. PURPOSE: The purpose of this study was to identify possible differences between strength and mobility measures in female volleyball student-athletes whose responsibilities include hitting (predominantly overhead roles) versus those who are primarily passers and diggers (non-overhead roles). METHODS: Thirteen Division I volleyball student-athletes who volunteered to participate in this study were divided into two groups - hitters (H; age = 19.6 ± 1.5 y, height = 180.7 ± 6.7 cm) and passers (P; age = 19.3 ± 1.2 y, height = 172.0 ± 10.0 cm). Players were tested on their shoulder range of motion (ROM) for internal rotation (IR), external rotation (ER), and flexion using a goniometer. Total ROM was identified as a sum of IR and ER. Hand grip strength was measured in the dominant hand using a hand grip dynamometer. All testing was completed by certified healthcare professionals prior to preseason following clearance by the team physician. Descriptive statistics were calculated as mean ± standard deviations. RESULTS: H had higher total ROM than P in both the right arm (158.6 ± 65.8° vs 144.1 ± 65.8°) and left arm (165.0 ± 67.8° vs 155.7 ± 69.7°). H had higher flexion than P in the right, dominant arm (176.9 ± 7.9° vs 171.5 ± 18.7°), but similar flexion in the left, nondominant arm (180.1 ± 5.6° vs 180.7 ± 3.4°). H and P both had higher than average values for shoulder ROM compared to published normative data. Hand grip strength was also higher in H compared to P (31.6 ± 6.2 kg vs 26.1 ± 2.5 kg). CONCLUSIONS: H displayed greater total ROM in both arms, a higher flexion ROM in their dominant arm than P as well as greater strength in their dominant arm. This emphasizes the importance of mobility and strength in their positional demands, and the need for shoulder stability. This information provides strength and conditioning coaches preliminary information on possible foci for training and areas where further research is still needed