Association of in-competition injury risk and the degree of rapid weight cutting prior to competition in division I collegiate wrestlers.

OBJECTIVES: Weight cutting is thought to offer a competitive advantage in wrestling. Dehydration has deleterious effects on physical and cognitive function, which may increase the risk of injury. The purpose of the study was to investigate whether the degree of weight cutting was associated with injury risk. METHODS: Data were collected prospectively in a cohort of collegiate wrestlers over seven seasons. Changes in weight, body fat and lean mass were measured during the preseason, at midseason and before competition. Cox proportional-hazard ratios were calculated for risk of in-competition injury. RESULTS: Among 67 unique division 1 collegiate wrestlers (163 athlete seasons), there were 53 unique injuries affecting 46 athletes. There was no difference in absolute weight change, per cent weight change, per cent body fat change or per cent lean mass change between injured and non-injured wrestlers from the preseason to midseason measurements. From midseason to competition weight, change in body weight was -7.0%±3.2% (-5.3 kg±2.6) in injured athletes compared with -5.7%±3.3% (-4.3 kg±2.5) in non-injured athletes. For every kilogram of body weight lost, wrestlers had a 14% increased hazard of injury (HR 1.14, 95% CI 1.04 to 1.25, p=0.004). For every 1% of body weight lost, wrestlers had an 11% increased hazard of injury (HR 1.11, 95% CI 1.03 to 1.19, p=0.005). CONCLUSION: Rapid weight cutting was associated with a higher risk of in-competition injuries in division 1 collegiate wrestlers. For every per cent in body weight lost, wrestlers had an 11% increased hazard of injury during competition.

Contribution of Lean Mass Distribution on Aerobic Fitness and Performance in NCAA Division I Female Rowers.

ABSTRACT: Haraldsdottir, K, Sanfilippo, J, Dawes, S, and Watson, A. Contribution of lean mass distribution on aerobic fitness and performance in NCAA division I female rowers. J Strength Cond Res 36(7): 1956-1960, 2022-The purpose of this study was to determine the relative influence of total lean body mass (LBM), body fat percentage (BF%), upper extremity lean mass (ULM), lower extremity lean mass (LLM), and trunk lean mass (TLM) on maximal aerobic capacity (V̇o2max) and time to exhaustion (Tmax) in female collegiate rowers. One hundred seven female collegiate rowers (aged 18-22 years) performed maximal progressive rowing ergometer testing to determine V̇o2max and Tmax. Body mass, LBM, BF%, ULM, LLM, and TLM were determined by using dual-energy x-ray absorptiometry. Separate multivariable linear regression models were performed to predict V̇o2max and Tmax by using LBM and BF% as predictors. In addition, separate linear regression models were used to predict V̇o2max and Tmax with ULM, LLM, and TLM as covariates. Subjects were aged 20 ± 3 years. V̇o2max was significantly predicted by LBM (r2 = 0.29, p < 0.001), but not BF% (r2 = 0.002, p = 0.79). Similarly, Tmax was significantly predicted by LBM (r2 = 0.25, p < 0.001), but not BF% (r2 = 0.003, p = 0.19). V̇o2max was significantly predicted by LLM (r2 = 0.12, p < 0.01), but not ULM (r2 = 0.08, p = 0.68) or TLM (r2 = 0.09, p = 0.17), and Tmax was significantly predicted by TLM (r2 = 0.09, p = 0.02), but not ULM (r2 = 0.07, p = 0.89) or LLM (r2 = 0.08, p = 32). Among female collegiate rowers, whole body LBM is a significant predictor of both V̇o2max and Tmax. However, LLM is a stronger predictor of V̇o2max while TLM is a stronger predictor Tmax, although each of these relationships has a low coefficient of determination. These findings suggest that aerobic fitness and performance may be influenced by regions of lean mass differently.

Lower step rate is associated with a higher risk of bone stress injury: a prospective study of collegiate cross country runners.

OBJECTIVES: To determine if running biomechanics and bone mineral density (BMD) were independently associated with bone stress injury (BSI) in a cohort of National Collegiate Athletic Association Division I cross country runners. METHODS: This was a prospective, observational study of 54 healthy collegiate cross country runners over three consecutive seasons. Whole body kinematics, ground reaction forces (GRFs) and BMD measures were collected during the preseason over 3 years via motion capture on an instrumented treadmill and total body densitometer scans. All medically diagnosed BSIs up to 12 months following preseason data collection were recorded. Generalised estimating equations were used to identify independent risk factors of BSI. RESULTS: Univariably, step rate, centre of mass vertical excursion, peak vertical GRF and vertical GRF impulse were associated with BSI incidence. After adjusting for history of BSI and sex in a multivariable model, a higher step rate was independently associated with a decreased risk of BSI. BSI risk decreased by 5% (relative risk (RR): 0.95; 95% CI 0.91 to 0.98) with each one step/min increase in step rate. BMD z-score was not a statistically significant risk predictor in the final multivariable model (RR: 0.93, 95% CI 0.85 to 1.03). No other biomechanical variables were found to be associated with BSI risk. CONCLUSION: Low step rate is an important risk factor for BSI among collegiate cross country runners and should be considered when developing comprehensive programmes to mitigate BSI risk in distance runners.

Athletes with a concussion history in the last two years have impairments in dynamic balance performance.

The purpose of this study was to determine if National Collegiate Athletics Association Division 1 American Football and Ice Hockey athletes with a history of concussion have impaired dynamic balance control when compared to healthy control athletes. This cross-sectional observational study recruited 146 athletes; 90 control athletes and 56 athletes with a history of concussion. Athletes were tested during a pre-season evaluation using the inertial-sensor instrumented Y Balance Test. Independent variables were normalized reach distance, gyroscope magnitude sample entropy, and jerk magnitude root mean square. Kruskal-Wallis H test and Dunn-Bonferroni analysis demonstrated that individuals with a concussion history within the last 2 years have statistically significantly lower jerk magnitude root mean square in the posteromedial (Z = 23.22, P = .015) and posterolateral (Z = 24.64, P = .010) reach directions, when compared to the control group. There was no significant difference between those who sustained a concussion longer than two years ago and the control group for the posteromedial (Z = -1.25; P = .889) and posterolateral (Z = 6.44; P = .469) directions. These findings show that athletes with a concussion history within the last two years possess dynamic balance deficits, when compared to healthy control athletes. Conversely, athletes whose injury occurred greater than 2 years ago possessed comparable performance to the healthy controls. This suggests that sensorimotor control deficits may persist beyond clinical recovery, for up to 2 years. Therefore, clinicians should integrate balance training interventions into the return-to-play process to accelerate sensorimotor recovery and mitigate the risk of future injury.

Preseason Aerobic Capacity Is an Independent Predictor of In-Season Injury in Collegiate Soccer Players.

PURPOSE: To determine whether preseason aerobic capacity is independently associated with in-season injury among collegiate soccer players. DESIGN: Prospective cohort study. SETTING: University athletic department. PARTICIPANTS: Forty-three NCAA Division I soccer athletes (male = 23). INDEPENDENT VARIABLES: Gender and preseason lean body mass (LBM), body fat percentage (BF%), and maximal aerobic capacity (V[Combining Dot Above]O2max). MAIN OUTCOME MEASURES: In-season injuries were recorded during the season, and body composition and fitness variables were compared between injured and uninjured players. Multivariate regression models were developed to predict injury during the entire season and during the first 4 weeks of the season. RESULTS: Thirty-five injuries among 25 players were recorded during the season. Players injured at any point during the season had lower V[Combining Dot Above]O2max (57.7 vs 63.4 mL·kg·min, P = 0.014) and Tmax (15.8 vs 17.2 minutes, P = 0.035), compared with uninjured players, but no differences were noted in age, gender, LBM, or BF%. Players injured during the first 4 weeks of the season had lower LBM (49.7 vs 56.0 kg, P = 0.038) and Tmax (15.1 vs 16.7 minutes, P = 0.043) than uninjured players. For injuries occurring throughout the entire season, V[Combining Dot Above]O2max was an independent predictor of injury (P = 0.043), whereas gender, LBM, and BF% were not. During the first 4 weeks of the season, V[Combining Dot Above]O2max (P = 0.035) and LBM (P = 0.049) were related to injury, whereas gender and BF% were not. CONCLUSIONS: Aerobic fitness is an independent predictor of in-season injury. Early-season injuries are related to aerobic fitness and LBM. CLINICAL RELEVANCE: Efforts to increase aerobic capacity and LBM among soccer players in the off-season may help reduce in-season injury.

A DXA Whole Body Composition Cross-Calibration Experience: Evaluation With Humans, Spine, and Whole Body Phantoms.

New densitometer installation requires cross-calibration for accurate longitudinal assessment. When replacing a unit with the same model, the International Society for Clinical Densitometry recommends cross-calibrating by scanning phantoms 10 times on each instrument and states that spine bone mineral density (BMD) should be within 1%, whereas total body lean, fat, and %fat mass should be within 2% of the prior instrument. However, there is limited validation that these recommendations provide adequate total body cross-calibration. Here, we report a total body cross-calibration experience with phantoms and humans. Cross-calibration between an existing and new Lunar iDXA was performed using 3 encapsulated spine phantoms (GE [GE Lunar, Madison, WI], BioClinica [BioClinica Inc, Princeton, NJ], and Hologic [Hologic Inc, Bedford, MA]), 1 total body composition phantom (BioClinica), and 30 human volunteers. Thirty scans of each phantom and a total body scan of human volunteers were obtained on each instrument. All spine phantom BMD means were similar (within 1%; <-0.010 g/cm2 bias) between the existing and new dual-energy X-ray absorptiometry unit. The BioClinica body composition phantom (BBCP) BMD and bone mineral content (BMC) values were within 2% with biases of 0.005 g/cm2 and -3.4 g. However, lean and fat mass and %fat differed by 4.6%-7.7% with biases of +463 g, -496 g, and -2.8%, respectively. In vivo comparison supported BBCP data; BMD and BMC were within ∼2%, but lean and fat mass and %fat differed from 1.6% to 4.9% with biases of +833 g, -860 g, and -1.1%. As all body composition comparisons exceeded the recommended 2%, the new densitometer was recalibrated. After recalibration, in vivo bias was lower (<0.05%) for lean and fat; -23 and -5 g, respectively. Similarly, BBCP lean and fat agreement improved. In conclusion, the BBCP behaves similarly, but not identical, to human in vivo measurements for densitometer cross-calibration. Spine phantoms, despite good BMD and BMC agreement, did not detect substantial lean and fat differences observed using BBCP and in vivo assessments. Consequently, spine phantoms are inadequate for dual-energy X-ray absorptiometry whole body composition cross-calibration.

Dual-energy X-ray absorptiometry measured regional body composition least significant change: effect of region of interest and gender in athletes.

Dual-energy X-ray absorptiometry (DXA) is widely used to evaluate body composition in athletes. Knowledge of measurement precision is essential for monitoring body composition changes over time. This study begins characterizing DXA body composition precision in 60 (30 males and 30 females) Division 1 athletes focusing on gender, regional, and tissue type differences. Two total body scans with repositioning between were performed on the same day. Least significant change (LSC) for the root-mean-square deviation (LSCRMSD) and the percent coefficient of variation (LSC%CV) for total, lean, and fat mass was calculated for 6 regions of interest. The effect of gender, region, tissue type, and mass on the standard deviation (SD) and percent coefficient of variation (%CV) between the 2 scans was evaluated using repeated measures regression analysis. Statistically significant effects of gender, region, tissue type, and mass on SD and %CV were noted. To generalize, a nonlinear positive relationship between LSCRMSD and mass and a nonlinear negative relationship between LSC%CV and mass were observed. In conclusion, DXA body composition LSC varies among genders, regions, tissues, and mass. As such, when evaluating serial body composition in athletes, especially if assessing regional change, knowledge of precision in individuals of similar body size and gender to the population of interest is needed.

Lean mass asymmetry influences force and power asymmetry during jumping in collegiate athletes.

The purpose of this investigation was to (a) examine how asymmetry in lower extremity lean mass influenced force and power asymmetry during jumping, (b) determine how power and force asymmetry affected jump height, and (c) report normative values in collegiate athletes. Force and power were assessed from each limb using bilateral force plates during a countermovement jump in 167 division 1 athletes (mass = 85.7 ± 20.3 kg, age = 20.0 ± 1.2 years; 103 men and 64 women). Lean mass of the pelvis, thigh, and shank was assessed using dual-energy x-ray absorptiometry. Percent asymmetry was calculated for lean mass at each region (pelvis, thigh, and shank) as well as force and power. Forward stepwise regressions were performed to determine the influence of lean mass asymmetry on force and power asymmetry. Thigh and shank lean mass asymmetry explained 20% of the variance in force asymmetry (R = 0.20, p < 0.001), whereas lean mass asymmetry of the pelvis, thigh, and shank explained 25% of the variance in power asymmetry (R = 0.25, p < 0.001). Jump height was compared across level of force and power asymmetry (p > 0.05) and greater than 10% asymmetry in power tended to decrease the performance (effect size >1.0). Ninety-five percent of this population (2.5th to 97.5th percentile) displayed force asymmetry between -11.8 and 16.8% and a power asymmetry between -9.9 and 11.5%. A small percentage (<4%) of these athletes displayed more than 15% asymmetry between limbs. These results demonstrate that lean mass asymmetry in the lower extremity is at least partially responsible for asymmetries in force and power. However, a large percentage remains unexplained by lean mass asymmetry.

Changes in Quality of Life Among Collegiate Athletes During COVID-19.

BACKGROUND: The COVID-19 pandemic has had a significant effect on the mental health of athletes. How this has affected quality of life (QoL), specifically in the college population, is poorly defined. HYPOTHESIS: During the COVID-19 pandemic, the mental and physical QoL will have decreased in collegiate athletes as compared with before the pandemic. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Division I athletes from a total of 23 varsity teams at a single institution completed surveys between 2018 and 2022. QoL was assessed using the Veterans RAND 12-Item Health Survey (VR-12). VR-12 scores were separated into mental component scores (MCS) and physical component scores (PCS). Separate linear mixed effects models evaluated changes in MCS and PCS from pre-COVID to during COVID overall, as well as differences in changes by sex and sport type (individual, team). RESULTS: For all athletes, the PCS increased (54.6 [95% CI 54.4-54.7] vs 55.1 [54.9-55.3]; P < 0.01) and the MCS decreased (55.2 [54.9-55.5] vs 53.5 [53.1-53.8]; P < 0.01) from pre-COVID to during COVID. When evaluating for sex, women demonstrated a greater increase in PCS (0.57 ± 0.22; P = 0.01) and greater decrease in MCS (1.06 ± 0.38; P < 0.01). With respect to sport type, individual sports demonstrated a greater decrease in MCS (1.46 ± 0.39; P < 0.01), but no interaction was identified for PCS (0.42 ± 0.23; P = 0.07). CONCLUSION: Collegiate athletes demonstrated a decrease in their self-reported mental QoL during the COVID-19 pandemic, as compared with before the pandemic. This effect was most evident in women and in individual sports. Athletes also reported an increase in physical QoL during COVID that was also larger in women, but not related to sport. CLINICAL RELEVANCE: This study demonstrates the impact of the COVID-19 pandemic on collegiate athletes' QoL, including negative effects on mental health. It also identifies cohorts of athletes (women, individual) who may be more significantly affected.

The Associations Between Wellbeing and Injury Differ by Time Loss in Collegiate Athletes.

BACKGROUND: Self-reported wellbeing measures such as mood and soreness have been identified as predictors of injury risk. However, most research has focused on investigating time-loss injuries even though nontime-loss injuries are more prevalent. HYPOTHESIS: Impairments in sleep and subjective wellbeing would be associated with increased injury for both time-loss and nontime-loss injuries. STUDY DESIGN: Prospective longitudinal study. LEVEL OF EVIDENCE: Level 3. METHODS: During 2022, 127 athletes completed a daily survey that inquired about training load and sleep from the previous day along with mood, stress, and soreness on the current day. Incidence of injury was also monitored using documentation provided by athletes' respective athletic trainers. Mixed effect models were used to analyze the relationship between wellbeing and sleep measures with injury. RESULTS: Self-reported wellbeing, based most closely on soreness the day of injury, by National Collegiate Athletic Association Division 1 collegiate athletes was predictive of time-loss injuries, whereas no significant relationship was identified for nontime-loss injuries. Specifically, 1 unit increase in soreness was associated with a 39% increase in odds of sustaining a time-loss injury. CONCLUSION: This study found that subjective wellbeing and sleep have a different relationship with injury dependent upon whether the resulting injury leads to time loss. CLINICAL RELEVANCE: Self-reported wellbeing appears to be a relevant predictor of injury among collegiate athletes for time-loss injuries.

Mindfulness Practice Is Associated With Improved Well-Being and Reduced Injury Risk in Female NCAA Division I Athletes.

BACKGROUND: Injury in sport is an inherent risk to participation, and it can have devastating consequences for the athlete, both mentally and physically. Previous research has found that impairments in well-being can increase the risk of injury, and that various forms of mindfulness training and practice can improve well-being and mental health in various populations. HYPOTHESIS: Mindfulness would be associated with greater well-being and lower risk of injury. STUDY DESIGN: Cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 21 female Division I athletes underwent a formal 6-week mindfulness training program and were encouraged to continue mindfulness exercises. The athletes completed daily surveys on their smartphones in relation to mood, muscle readiness (soreness), readiness to train, energy level, daily training load, and whether they had participated in mindfulness training that day. Linear mixed effects models were used to evaluate well-being variables and mindfulness state, and separate mixed effects logistics regression models were used to evaluate injury incidence and wellness variables. RESULTS: On days with mindfulness practice, athletes reported higher mood (19.6 [18.8-20.3] vs 19.4 [18.6-20.1, P = 0.03), muscle readiness (18.9 [17.8-20.0] vs 18.6 [17.5-19.6], P = 0.03), readiness to train (78.7 [75.9-81.5] vs 77.4 [74.7-80.2], P < 0.01), and energy level (19.3 [18.6-20.1] vs 18.8 [18.1-19.5, P < 0.01) than on the days when they did not participate in mindfulness training. Mindfulness practice was associated with significantly reduced likelihood of suffering an acute injury the following day (odds ratio, 0.42; 95% CI, 0.42-0.43; P < 0.01). CONCLUSION: On an individual level, participation in mindfulness by female collegiate athletes was associated with a dramatic reduction in injury risk the following day. In addition, mindfulness was associated with significantly improved mood, muscle readiness, readiness to train, and energy level. CLINICAL RELEVANCE: These findings suggest that mindfulness training in athletes may improve well-being and reduce the risk of injury among high-level athletes.

Anxiety and Depression Prevalence in Incoming Division I Collegiate Athletes From 2017 to 2021.

BACKGROUND: Young adults report increased rates of anxiety and depression than other age groups. Furthermore, young adult athletes experience additional stressors that may negatively impact their mental health. The aim of this study was to investigate the prevalence of anxiety and depression symptoms among Division I collegiate athletes and the influences of sex, sport type, and distance from home. HYPOTHESIS: It was hypothesized that self-reported levels of anxiety and depression would increase among this population during this timeframe. STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 3. METHODS: Participants included 792 incoming Division I collegiate athletes. The Generalized Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9) scores were completed by all incoming student athletes at a single institution as part of their preparticipation examination over 5 years. Both survey scores were categorized into different levels of severity and separately compared with chi-square tests. Continuous scores were modeled separately using negative binomial regression models including year, sex, sport type, and home location as covariates. RESULTS: Results showed consistent levels of anxiety and depression over time. Female athletes reported higher levels of both anxiety and depression than male athletes, and individual sport athletes reported higher levels of depression than team sport athletes. Distance from home was not associated with anxiety or depression levels. CONCLUSION: Overall, levels of anxiety and depression did not change in this population over this time period. However, differences in anxiety and depression were seen between sexes and depression between sport types. CLINICAL RELEVANCE: Understanding anxiety and depression risk factors among collegiate athletes can enhance early identification and intervention to improve mental health and allow for better allocation of resources to at-risk groups among Division I collegiate athletes.

Preseason Eccentric Strength Is Not Associated with Hamstring Strain Injury: A Prospective Study in Collegiate Athletes.

INTRODUCTION: Established risk factors for hamstring strain injuries (HSI) include older age and prior HSI. However, these are nonmodifiable and have a limited role in injury prevention. Eccentric hamstring strength is a common component of HSI prevention programs, but its association with injury is less clear. PURPOSE: This study aimed to determine if eccentric hamstring strength was prospectively associated with HSI among collegiate athletes, while controlling for sex, age, and prior HSI. We hypothesized that athletes with lower eccentric hamstring strength or greater between-limb strength asymmetry at preseason would have an increased risk of HSI. METHODS: Hamstring eccentric strength measures, maximum total force ( FTotal ) and between-limb asymmetry in maximum force ( FAsym ), were measured at preseason on male and female athletes. HSIs were tracked over the subsequent 12 months. Generalized estimating equations were used to identify univariable and multivariable associations between athlete demographics, eccentric hamstring strength, and HSI risk. RESULTS: Data for 326 athletes (85 female; 30 track, 43 basketball, 160 American football, 93 soccer) were included, and 64 HSIs were observed. Univariable associations between eccentric hamstring strength and subsequent HSI were nonsignificant ( FTotal : odds ratio [OR], 0.99 (95% confidence interval (CI), 0.93-1.05); P = 0.74; FAsym : OR, 1.35 (95% CI, 0.87-2.09); P = 0.23). No relationship between eccentric hamstring strength and HSI ( FAsym : OR, 1.32 (95% CI, 0.84-2.08); P = 0.23) was identified after adjusting for confounders including sex, age, and prior HSI. CONCLUSIONS: No association between preseason eccentric hamstring strength and risk of subsequent HSI was identified after controlling for known risk factors and sex among collegiate athletes. Eccentric hamstring strengthening may continue to serve as a preventative approach to HSI, but it does not provide additional insight into HSI risk beyond factors such as age and prior HSI.

Comparing High School Sport Specialization Trends Between Division I and Club Collegiate Athletes.

BACKGROUND: Adolescent athletes report that sports specialization improves their ability to receive a collegiate athletics scholarship, though this is not well-understood. The purpose of this study was to examine self-reported trends in high school specialization and influences for sport participation between Division I (D-I) and college-aged club (club) athletes. HYPOTHESIS: There would be no difference in high school sport specialization or sport participation influences between D-I and club athletes. STUDY DESIGN: Retrospective cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A survey included specialization classification (low, moderate, and high) for 9th to 12th grade, age that the athlete started organized sport and his or her collegiate sport, and several influential factors for participation in one's primary high school sport (1 = no influence to 5 = extremely influential). Chi-square analyses were used to compare specialization classifications between groups. Nonparametric tests were used to determine significant differences in age-related variables and influential factors between D-I and club athletes. All analysis were also conducted with boys and girls separately. RESULTS: Participants included 266 D-I (girls, 155; 58%) and 180 club (girls, 122; 68%) athletes. Club athletes were more likely to be classified as low specialization at every grade in high school, and this difference was more pronounced between D-I and club female athletes than male athletes. The number of years an athlete was classified as highly specialized in high school was not different between D-I and club athletes. Club athletes were more influenced by playing with friends than D-I athletes and D-I athletes were more influenced by pursuing a collegiate scholarship than club athletes. CONCLUSION: High levels of specialization in high school sport may not be necessary for playing at the collegiate level, though some level of specialization in high school might be necessary. CLINICAL RELEVANCE: Clinicians should advocate for healthy long-term athlete development, which does not support high specialization in high school sports.

Decreased Sleep and Subjective Well-Being as Independent Predictors of Injury in Female Collegiate Volleyball Players.

BACKGROUND: The relationship among sleep duration, subjective well-being, and injury risk in athletes is poorly defined. PURPOSE: To evaluate the independent effects of sleep duration, sleep quality, and subjective well-being on in-season injuries in collegiate female volleyball athletes. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: During a 9-month competitive season, 17 female National Collegiate Athletic Association (NCAA) Division I volleyball players reported mood, fatigue, stress, soreness, sleep duration (hours), and sleep quality every morning. Well-being measures were recorded from 0 (worst) to 5 (best), and all time-loss injuries were recorded by the team athletic trainer. Separate mixed-effects logistic regression models were used to evaluate the effects of sleep and subjective well-being on in-season injury. Each well-being variable was also included in a separate mixed-effects logistic regression model with sleep duration as a covariate. RESULTS: A total of 54 injuries were recorded during the study period. Compared with days without an injury, mood, fatigue, stress, soreness, sleep quality, and sleep duration were significantly worse the day before an injury occurred. In the separate prediction models, in-season injury was significantly predicted by fatigue (odds ratio [OR], 0.56 [95% CI, 0.36-0.86]; P = .008), mood (OR, 0.52 [95% CI, 0.35-0.78]; P = .002), stress (OR, 0.63 [95% CI, 0.42-0.94]; P = .023), soreness (OR, 0.54 [95% CI, 0.38-0.79]; P = .001), sleep quality (OR, 0.49 [95% CI, 0.34-0.7]; P < .001), and sleep duration (OR, 0.69 [95% CI, 0.55-0.87]; P = .001). In the multivariable models, sleep duration remained a significant independent predictor in each of the subsequent multivariable models (OR, 0.72-0.74; P < .05 for all), as did mood (OR, 0.55 [95% CI, 0.36-0.83); P = .005) and soreness (OR, 0.57 [95% CI, 0.39-0.83]; P = .003), while fatigue (OR, 0.65 [95% CI, 0.42-1]; P = .054) and stress (OR, 0.68 [95% CI, 0.45-1]; P = .061) no longer reached statistical significance. CONCLUSION: Increased sleep duration, mood, and decreased soreness were independently associated with a reduced risk of in-season injury in this cohort of female NCAA volleyball players.

Decreased Sleep Is an Independent Predictor of In-Season Injury in Male Collegiate Basketball Players.

BACKGROUND: Although decreased sleep has been associated with decreased performance, increased illness risk, and impaired well-being in athletes, the relationship between sleep and injury risk in collegiate athletes is unknown. PURPOSE/HYPOTHESIS: To evaluate the independent effects of sleep duration and subjective well-being on in-season injury in male collegiate basketball athletes. We hypothesized that decreased sleep would be associated with an increased risk of in-season injury. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: During 2 consecutive seasons, 19 male National Collegiate Athletic Association Division I basketball players reported mood, fatigue, stress, soreness, sleep duration (hours), and previous day's training load every morning. Well-being measures were recorded on a scale from 0 (worst) to 5 (best), and all time-loss injuries were recorded by the team athletic trainer. Separate mixed-effects logistic regression models were used to evaluate the effects of sleep and subjective well-being on in-season injury, with adjustment for same-day training load and individual repeated measures. To determine the independence of sleep and well-being as predictors of injury, each well-being variable was included in a separate mixed-effects logistic regression model, with sleep and training load as covariates. RESULTS: During the study period, 32 injuries were recorded. In the initial separate prediction models, in-season injury was significantly predicted by mood (odds ratio [OR], 0.50; 95% CI, 0.37-0.66), fatigue (OR, 0.44; 95% CI, 0.33-0.59), stress (OR, 0.57; 95% CI, 0.42-0.76), soreness (OR, 0.41; 95% CI, 0.32-0.54), and sleep duration (OR, 0.57; 95% CI, 0.49-0.66) (P < .001 for all). In the multivariable models, sleep duration remained a significant, independent predictor in each of the subsequent multivariable models (OR, 0.52-0.69; P < .001 for all) as did soreness (OR, 0.65; 95% CI, 0.44-0.95; P = .024), whereas mood (OR, 1.2; 95% CI, 0.76-1.9; P = .43), fatigue (OR, 1.1; 95% CI, 0.65-1.9; P = .68), and stress (OR, 1.1; 95% CI, 0.75-1.5; P = .69) were no longer significant. CONCLUSION: Increased sleep duration is independently associated with a reduced risk of in-season injury in male collegiate basketball players, even after adjustment for training load and subjective well-being. The effects of mood, fatigue, and stress on injury were no longer evident after adjustment for the effect of sleep duration.

Dual-Energy X-Ray Absorptiometry Body Composition in NCAA Division I Athletes: Exploration of Mass Distribution.

BACKGROUND: Body composition assessment is frequently used in sports medicine and athletic performance environments to assess change in response to strength training and nutrition programs. However, to effectively do so requires knowledge regarding expected body composition values relative to sport and sex. Dual-energy x-ray absorptiometry (DXA) is widely used to evaluate body composition, although its utility in relationship to specific sports, performance, or rehabilitation is not clearly defined. HYPOTHESIS: Body composition metrics and distribution of National Collegiate Athletic Association Division I collegiate athletes will vary based on sport and sex. LEVEL OF EVIDENCE: Level 4. STUDY DESIGN: Cross-sectional study. METHODS: A convenience sample of 337 athletes (229 men and 108 women) participating in football, wrestling, soccer, hockey, basketball, golf, softball, or volleyball was evaluated. DXA-measured total body composition, including bone mineral density (BMD), % lean mass, % fat, and regional distribution, were compared by sex, sport, and with an age-matched National Health and Nutrition Examination Survey (NHANES) population. RESULTS: Men had higher BMD, lower % fat (16.4% vs 25.2%) and higher % lean mass (79.2% vs 70.6%) (P < 0.001). Regional composition varied by sport and sex, with women having a greater proportion of lean mass at the trunk and men in their arms (P < 0.0001). Leg lean mass was distributed similarly between sexes (35%). Overall, the normative group (NHANES) had lower BMD and higher percentage fat. CONCLUSION: DXA-measured body composition and lean mass distribution varies by sport and sex in Division I athletes. The observed difference to the NHANES population emphasizes challenges in identifying appropriate comparison populations, reinforcing the need to compare athletes with their own baseline. CLINICAL RELEVANCE: These findings establish a framework to investigate the relevance of these variances and determine the utility of body composition analysis in elite athletes.

Star Excursion Balance Test Anterior Asymmetry Is Associated With Injury Status in Division I Collegiate Athletes.

Study Design Retrospective cohort. Background Star Excursion Balance Test (SEBT) performance differs by sport in healthy collegiate athletes, and lower extremity injury rates also vary by sport, sex, and athletic exposure. The relationship between SEBT performance and injury risk has not been evaluated with consideration of these additional variables, which may be necessary to fully describe the relationship between SEBT performance and injury risk. Objectives To assess the association between preseason SEBT performance and noncontact injury occurrence to the knee or ankle in Division I collegiate athletes when controlling for sport, sex, and athletic exposure. Methods Star Excursion Balance Test performance, starting status, and injury status were reviewed retrospectively in National Collegiate Athletic Association Division I collegiate athletes from a single institution. A total of 147 athletes were healthy at the time of preseason SEBT testing and either remained healthy (n = 118) or sustained a noncontact injury to the knee or ankle (n = 29) during their sport's subsequent competitive season. Side-to-side asymmetries were calculated in each direction as the absolute difference in reach distance between limbs. Star Excursion Balance Test reach distances and asymmetries were compared between groups using multivariable regression, controlling for sport, sex, and athletic exposure (starter, nonstarter). Receiver operating characteristic curves were used to determine optimal sensitivity and specificity for significant models. Results When controlling for sport, sex, and athletic exposure, SEBT side-to-side asymmetry in the anterior direction, expressed as an absolute or normalized to limb length, discriminated between injured and noninjured athletes (area under the curve greater than 0.82). Conclusion Assessing side-to-side reach asymmetry in the anterior direction of the SEBT may assist in identifying collegiate athletes who are at risk for sustaining noncontact injuries to the knee or ankle. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2017;47(5):339-346. Epub 29 Mar 2017. doi:10.2519/jospt.2017.6974.

High School Sport Specialization Patterns of Current Division I Athletes.

BACKGROUND: Sport specialization is a strategy to acquire superior sport performance in 1 sport but is associated with increased injury risk. Currently, the degree of high school specialization among Division I athletes is unknown. HYPOTHESIS: College athletes will display increased rates of specialization as they progress through their high school careers. STUDY DESIGN: Descriptive epidemiological study. LEVEL OF EVIDENCE: Level 4. METHODS: Three hundred forty-three athletes (115 female) representing 9 sports from a Midwest Division I University completed a previously utilized sport specialization questionnaire regarding sport participation patterns for each grade of high school. McNemar and chi-square tests were used to investigate associations of grade, sport, and sex with prevalence of sport specialization category (low, moderate, high) (a priori P ≤ 0.05). RESULTS: Specialization increased throughout high school, with 16.9% (n = 58) and 41.1% (n = 141) of athletes highly specialized in 9th and 12th grades, respectively. Football athletes were less likely to be highly specialized than nonfootball athletes for each year of high school ( P < 0.001). There was no difference in degree of specialization between sexes at any grade level ( P > 0.23). CONCLUSION: The majority of Division I athletes were not classified as highly specialized throughout high school, but the prevalence of high specialization increased as athletes progressed through high school. Nonfootball athletes were more likely to be highly specialized than football athletes at each grade level. CLINICAL RELEVANCE: Most athletes who are recruited to participate in collegiate athletics will eventually specialize in their sport, but it does not appear that early specialization is necessary to become a Division I athlete. Athletes should be counseled regarding safe participation in sport during high school to minimize injury and maximize performance.