Epidemiology of National Collegiate Athletic Association men's and women's swimming and diving injuries from 2009/2010 to 2013/2014.

BACKGROUND: Recent injury data for collegiate-level swimming and diving are limited. This study describes the epidemiology of men's and women's swimming and diving injuries reported by the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) during the 2009/2010 to 2013/2014 academic years. METHODS: Injuries and athlete-exposure (AE) data reported within 9 men's and 13 women's swimming and diving programmes were analysed. Injury rates, injury rate ratios (IRR), and injury proportions by body site, diagnosis and mechanism were reported with 95% CIs. RESULTS: The ISP captured 149 and 208 injuries for men's and women's swimming and diving, respectively, leading to injury rates of 1.54/1000 and 1.71/1000 AEs. Among females, divers had a higher injury rate (2.49/1000 AEs) than swimmers (1.63/1000 AEs; IRR=1.53; 95% CI 1.07 to 2.19). Injury rates for male divers (1.94/1000 AEs) and swimmers (1.48/1000 AEs) did not differ (IRR=1.33; 95% CI 0.85 to 2.31). Most injuries occurred to the shoulder, resulted in strains and were classified as overuse or non-contact. Female swimmers had a higher overuse injury rate (1.04/1000 AEs) than male swimmers (0.66/1000 AEs; IRR=1.58; 95% CI 1.14 to 2.19). Overuse injury rates for female divers (0.54/1000 AEs) and male divers (0.46/1000 AEs) did not differ (IRR=1.16; 95% CI 0.40 to 3.34). Injury rates in 2012/2013-2013/2014 were lower than those in 2009/2010-2011/2012 for women's swimming (IRR=0.70; 95% CI 0.52 to 0.95) and diving (IRR=0.56; 95% CI 0.30 to 1.08), respectively. No time trends existed for men's swimmers or divers. CONCLUSIONS: Shoulder, strain and overuse injuries were common in collegiate men's and women's swimming and diving. Female swimmers were more likely to suffer an overuse injury than male swimmers. In addition, divers may have higher injury rates than swimmers, although small reported numbers warrant additional research.

Development and validation of a movement and activity in physical space score as a functional outcome measure.

OBJECTIVE: To develop and validate a functional measure, the Movement and Activity in Physical Space (MAPS) score, that encompasses both physical activity and environmental interaction. DESIGN: Observational matched-pair cohort with 2-month follow-up. SETTING: General community under free-living conditions. PARTICIPANTS: Adult participants (N=18; n=9 postsurgical, n=9 matched control; mean age ± SD, 28.9 ± 12.0y) were monitored by an accelerometer and global positioning system receiver for 3 days within 1 week (4.1 ± 2.8d) after knee surgery (T=0) and 2 months later (T+2). The healthy controls were matched for age, sex, smoking, perceived physical activity level, and occupation of a postsurgical participant. Correlation, t test (with Bonferroni adjustment: α=.05/2), analysis of variance, and intraclass correlation coefficient were used to establish validity and reliability evidence. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: MAPS scores. RESULTS: MAPS scores were moderately correlated with the Knee Injury and Osteoarthritis Outcome Score (P<.05). There was a significant group difference at T = 0 for MAPS (t(9.9)=-3.60; P=.01). Analysis of variance results for the MAPS indicated a time and group interaction (F(1,12)=4.60, P=.05). Reliability of 3 days of MAPS scores ranged from 0.75 to 0.81 (postsurgical and control), and 2-month test-retest reliability in the control group was 0.94. CONCLUSIONS: The results provide a foundation of convergent and known-group difference validity evidence along with reliability evidence for the use of MAPS as a functional outcome measure.

Effect of exercise training on walking mobility in multiple sclerosis: a meta-analysis.

OBJECTIVE: The study used meta-analytic procedures to examine the overall effect of exercise training interventions on walking mobility among individuals with multiple sclerosis. METHODS: A search was conducted for published exercise training studies from 1960 to November 2007 using MEDLINE, PsychINFO, CINAHL, and Current Contents Plus. Studies were selected if they measured walking mobility, using instruments identified as acceptable walking mobility constructs and outcome measures for individuals with neurologic disorders, before and after an intervention that included exercise training. RESULTS: Forty-two published articles were located and reviewed, and 22 provided enough data to compute effect sizes expressed as Cohen's d. Sixty-six effect sizes were retrieved from the 22 publications with 600 multiple sclerosis participants and yielded a weighted mean effect size of g = 0.19 (95% confidence interval, 0.09-0.28). There were larger effects associated with supervised exercise training ( g = 0.32), exercise programs that were less than 3 months in duration (g = 0.28), and mixed samples of relapsing-remitting and progressive multiple sclerosis (g = 0.52). CONCLUSIONS: The cumulative evidence supports that exercise training is associated with a small improvement in walking mobility among individuals with multiple sclerosis.

Calibration of accelerometer output for ambulatory adults with multiple sclerosis.

UNLABELLED: Motl RW, Snook EM, Agiovlasitis S, Suh Y. Calibration of accelerometer output for ambulatory adults with multiple sclerosis. OBJECTIVES: To examine the association between the rates of accelerometer activity counts and energy expenditure during walking in persons with multiple sclerosis (MS) versus controls and then to calibrate the output of accelerometers for computing time spent in light, moderate, and vigorous physical activity based on common metabolic equivalent unit categories in persons with MS. DESIGN: Mixed-model design. SETTING: Laboratory. PARTICIPANTS: People with MS (n=24) and people without MS (n=24) who were similar in age, sex, height, and weight. INTERVENTIONS: The participants undertook three 6-minute periods of walking at 3.2, 4.8, and 6.4km.h(-1) on a motor-driven treadmill. MAIN OUTCOME MEASURES: Activity counts and energy expenditure were measured with an accelerometer worn on the right hip and open-circuit spirometry, respectively. RESULTS: The results indicated that (1) persons with MS had greater energy expenditure, but not activity counts, during walking on a treadmill than did controls; (2) there was a strong linear relationship between activity counts and energy expenditure during treadmill walking, but the slope of the relationship was steeper in persons with MS than in controls; and (3) the cut-points for light, moderate, and vigorous physical activity were lower in persons with MS than in controls. CONCLUSIONS: Such findings provide evidence for a strong linear relationship between activity counts and energy expenditure during walking in persons with MS and cut-points based on counts per minute for quantifying time spent in light, moderate, and vigorous physical activity using accelerometers in this population.

Effect of a 4-week period of unloaded leg cycling exercise on spasticity in multiple sclerosis.

We conducted a small pilot study that examined the effect of a 4-week period of unloaded leg cycling on spasticity in individuals with multiple sclerosis (MS). The sample included 22 individuals with MS who were assigned using a quasi-experimental method into either exercise (n = 12) or control (n = 10) conditions. The exercise condition consisted of unloaded leg cycling for 30 minutes per session, 3 times per week, across a 4-week period. The control condition served as a control for passage of time and instrumentation effects. The H-reflex, modified Ashworth scale (MAS), and Multiple Sclerosis Spasticity Scale (MSSS-88) were collected before, 1-day after, and 1 and 4 weeks after the 4-week period. The 4-week period of unloaded leg cycling exercise was not associated with reductions in the H-reflex or MAS, whereas the exercise condition was associated with a reduction in MSSS-88 scores. This pattern of results suggests that chronic, unloaded leg cycling exercise is associated with improvements in spasticity from the participant's perspective, but neither improves nor worsens spasticity from electrophysiological and clinical perspectives.

Physical activity and quality of life in multiple sclerosis: intermediary roles of disability, fatigue, mood, pain, self-efficacy and social support.

Physical activity has been associated with a small improvement in quality of life (QOL) among those with multiple sclerosis (MS). This relationship may be indirect and operate through factors such as disability, fatigue, mood, pain, self-efficacy and social support. The present study examined variables that might account for the relationship between physical activity and QOL in a sample (N = 292) of individuals with a definite diagnosis of MS. The participants wore an accelerometer for 7 days and then completed self-report measures of physical activity, QOL, disability, fatigue, mood, pain, self-efficacy and social support. The data were analysed using covariance modelling in Mplus 3.0. The model provided an excellent fit for the data (chi(2) = 51.33, df = 18, p < 0.001, standardised root mean squared residual = 0.03, comparative fit index = 0.98). Those who were more physically active reported lower levels of disability (gamma = -0.50), depression (gamma = -0.31), fatigue (gamma = -0.46) and pain (gamma = -0.19) and higher levels of social support (gamma = 0.20), self-efficacy for managing MS (gamma = 0.41), and self-efficacy for regular physical activity (gamma = 0.49). In turn, those who reported lower levels of depression (beta = -0.37), anxiety (beta = -0.15), fatigue (beta = -0.16) and pain (beta = -0.08) and higher levels of social support (beta = 0.26) and self-efficacy for controlling MS (beta = 0.17) reported higher levels of QOL. The observed pattern of relationships supports the possibility that physical activity is indirectly associated with improved QOL in individuals with MS via depression, fatigue, pain, social support and self-efficacy for managing MS.

Cortical recruitment during selective attention in multiple sclerosis: an fMRI investigation of individual differences.

Recent studies with multiple sclerosis (MS) participants have provided evidence for cortical reorganization. Greater recruitment of task-related areas and additional brain regions are thought to play an adaptive role in the performance of cognitive tasks. In this study, we compared cortical circuitry recruited by MS patients and controls during a selective attention task that requires both focusing attention on task-relevant information and ignoring or inhibiting task-irrelevant information. Despite comparable behavioral performance, MS patients demonstrated increased neural recruitment of task-related areas along with additional activation of the prefrontal cortices. However, this additional activation was associated with poor behavioral performance, thereby providing evidence against compensatory brain reorganization. Future studies specifically investigating the nature of additional activation seen in MS patients in a wider variety of cognitive tasks would provide insight into the specific cognitive decline in MS.

Does the relationship between physical activity and quality of life differ based on generic versus disease-targeted instruments?

BACKGROUND: There has been an increased interest in the study of physical activity and its relationship with quality of life (QOL) and health-related quality of life (HRQL) in chronic disease conditions. The investigations have used either generic or disease-targeted instruments for measuring QOL and HRQL, but have not examined differences in the associations as a function of the types of instruments. PURPOSE: The present study examined the associations among physical activity, QOL, and HRQL using generic and disease-targeted instruments in persons with multiple sclerosis (MS). METHODS: Participants were 292 individuals with MS who wore an accelerometer for 7 days and then completed the Godin Leisure-Time Exercise Questionnaire (GLTEQ), Multiple Sclerosis Impact Scale-29 (MSIS-29), Leeds Multiple Sclerosis Quality of Life Scale (LMSQOL), Short Form-12 Health Survey (SF-12), and Satisfaction With Life Scale (SWLS). RESULTS: Accelerometer counts and GLTEQ scores had similarly sized correlations with scores from generic (SF-12) and the disease-specific (MSIS-29) measures of HRQL and generic (SWLS) and the disease-specific (LMSQOL) measures of QOL. Path analysis indicated a similar pattern of directional relationships between accelerometer counts and GLTEQ scores with physical and mental HRQL and, in turn, physical and mental HRQL with QOL using generic and disease-targeted instruments. CONCLUSIONS: Our results suggest that in cross-sectional analysis, physical activity is similarly related with QOL and HRQL using generic and disease-targeted instruments in persons with MS.

Confirmation and extension of the validity of the Multiple Sclerosis Walking Scale-12 (MSWS-12).

OBJECTIVE: The Multiple Sclerosis Walking Scale-12 (MSWS-12) is a 12-item patient-rated measure of the impact of MS on walking. As validation of scores from a measure is an ongoing and evolving process, the provision of additional evidence is warranted that confirms and extends the validity of inferences from scores on the MSWS-12. METHOD: Participants (N=133) were recruited through support group meetings of the Greater Illinois and Indiana State Chapters of the National Multiple Sclerosis Society, and wore an accelerometer for a seven-day period and completed the MSWS-12 and other outcome measures. RESULTS: Confirmatory factor analysis indicated that a single-factor model provided an adequate fit for MSWS-12 scores. MSWS-12 scores demonstrated strong evidence of internal consistency. The correlations between MSWS-12 scores with scores from other scales, including an accelerometer, were consistent with our a priori hypotheses. CONCLUSION: We provide evidence that both confirms and extends the validity of inferences from scores of the MSWS-12 as a measure of the impact of MS on walking in a community-based sample of individuals with MS.

Physical activity correlates with neurological impairment and disability in multiple sclerosis.

This study examined the correlation of physical activity with neurological impairment and disability in persons with multiple sclerosis (MS). Eighty individuals with MS wore an accelerometer for 7 days and completed the Symptom Inventory (SI), Performance Scales (PS), and Expanded Disability Status Scale. There were large negative correlations between the accelerometer and SI (r = -0.56; rho = -0.58) and Expanded Disability Status Scale (r = -0.60; rho = -0.69) and a moderate negative correlation between the accelerometer and PS (r = -0.39; rho = -0.48) indicating that physical activity was associated with reduced neurological impairment and disability. Such findings provide a preliminary basis for using an accelerometer and the SI and PS as outcome measures in large-scale prospective and experimental examinations of the effect of physical activity behavior on disability and dependence in MS.

Symptoms and physical activity behavior in individuals with multiple sclerosis.

We examined overall and specific symptoms as correlates of physical activity in individuals with multiple sclerosis (MS). Participants (N = 133) completed questionnaires that measured overall symptoms; and specific symptoms of depression, pain, and fatigue; difficulty walking; and physical activity. Initial analyses indicated that higher levels of overall symptoms (r = -.50), fatigue (r = -.26), and difficulty walking (r = -.46) were associated with lower levels of physical activity. Path analysis demonstrated that higher levels of overall symptoms were directly and indirectly associated with lower levels of physical activity; the indirect pathway involved difficulty walking (gamma beta = -.17). Such findings indicate that walking difficulty may partially explain the negative relationship between overall symptoms and physical activity behavior in MS.

Demographic correlates of physical activity in individuals with multiple sclerosis.

PURPOSE: There is limited information about the demographic characteristics associated with participation in physical activity among those with multiple sclerosis (MS). Hence, the present study examined 12 demographic variables in association with physical activity in a sample of individuals with MS. METHOD: Participants were 196 individuals with MS from the Midwestern portion of the United States. The participants provided demographic information and then wore a pedometer for a seven-day period. RESULTS: Analyses indicated that increasing age, use of a cane for ambulation, unemployment, and primary and secondary progressive MS were independently associated with less physical activity participation in this sample of MS patients. CONCLUSION: Individuals with those characteristics are likely to be inactive and in need of a targeted intervention for increasing their participation in physical activity.

Effect of acute leg cycling on the soleus H-reflex and modified Ashworth scale scores in individuals with multiple sclerosis.

This study examined the effect of a single bout of unloaded leg cycling on the soleus H-reflex and modified Ashworth scale (MAS) in 27 individuals with multiple sclerosis (MS) who had spasticity of the leg muscles, but were not currently taking anti-spastic medications. The soleus H-reflex and MAS data were collected before and 10, 30, and 60 min after 20 min of unloaded leg cycling and a control condition. The acute bout of unloaded leg cycling resulted in concomitant and prolonged reductions in the soleus H-reflex and MAS scores compared with the control condition. This provides converging evidence for the anti-spastic potential of acute unloaded leg cycling in individuals with MS.

Validity of physical activity measures in ambulatory individuals with multiple sclerosis.

PURPOSE: The literature suggests that individuals with multiple sclerosis (MS) engage in less physical activity than non-diseased individuals. That conclusion, however, depends upon the validity of scores from measures of physical activity among the MS population. This study evaluated the validity of scores from two self-report surveys, a pedometer, and an accelerometer and during seven days of free-living conditions among individuals with MS. METHOD: Participants were 30 individuals (28 females, two males) with an established definite diagnosis of MS. The participants wore a pedometer and a single-axis accelerometer during the waking hours of a 7-day period. After the 7-day period, participants returned to the lab and completed a self-administered physical activity questionnaire and then underwent a 7-day physical activity recall. RESULTS: There were strong correlations (a) between scores from the two self-report measures of physical activity and (b) between scores from the two objective measures of physical activity, and (c) weaker, but moderate-to-strong correlations between scores from the self-report and objective measures of physical activity. CONCLUSION: Our results support the quantification of physical activity among those with MS using validated self-report and objective measures.

Concussion-Related Protocols and Preparticipation Assessments Used for Incoming Student-Athletes in National Collegiate Athletic Association Member Institutions.

CONTEXT: National Collegiate Athletic Association (NCAA) legislation requires that member institutions have policies to guide the recognition and management of sport-related concussions. Identifying the nature of these policies and the mechanisms of their implementation can help identify areas of needed improvement. OBJECTIVE: To estimate the characteristics and prevalence of concussion-related protocols and preparticipation assessments used for incoming NCAA student-athletes. DESIGN: Cross-sectional study. SETTING: Web-based survey. PATIENTS OR OTHER PARTICIPANTS: Head athletic trainers from all 1113 NCAA member institutions were contacted; 327 (29.4%) completed the survey. INTERVENTION(S): Participants received an e-mail link to the Web-based survey. Weekly reminders were sent during the 4-week window. MAIN OUTCOME MEASURE(S): Respondents described concussion-related protocols and preparticipation assessments (eg, concussion history, neurocognitive testing, balance testing, symptom checklists). Descriptive statistics were compared by division and football program status. RESULTS: Most universities provided concussion education to student-athletes (95.4%), had return-to-play policies (96.6%), and obtained the number of previous concussions sustained by incoming student-athletes (97.9%). Fewer had return-to-learn policies (63.3%). Other concussion-history-related information (e.g., symptoms, hospitalization) was more often collected by Division I universities. Common preparticipation neurocognitive and balance tests were the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT; 77.1%) and Balance Error Scoring System (46.5%). In total, 43.7% complied with recommendations for preparticipation assessments that included concussion history, neurocognitive testing, balance testing, and symptom checklists. This was due to moderate use of balance testing (56.6%); larger proportions used concussion history (99.7%), neurocognitive testing (83.2%), and symptom checklists (91.7%). More Division I universities (55.2%) complied with baseline assessment recommendations than Division II (38.2%, χ2 = 5.49, P = .02) and Division III (36.1%, χ2 = 9.11, P = .002) universities. CONCLUSIONS: National Collegiate Athletic Association member institutions implement numerous strategies to monitor student-athletes. Division II and III universities may need additional assistance to collect in-depth concussion histories and conduct balance testing. Universities should continue developing or adapting (or both) return-to-learn policies.

Incidence of Concussion During Practice and Games in Youth, High School, and Collegiate American Football Players.

IMPORTANCE: A report by the Institute of Medicine called for comprehensive nationwide concussion incidence data across the spectrum of athletes aged 5 to 23 years. OBJECTIVE: To describe the incidence of concussion in athletes participating in youth, high school, and collegiate American football. DESIGN, SETTING, AND PARTICIPANTS: Data were collected by athletic trainers at youth, high school, and collegiate football practices and games to create multiple prospective observational cohorts during the 2012 and 2013 football seasons. Data were collected from July 1, 2012, through January 31, 2013, for the 2012 season and from July 1, 2013, through January 31, 2014, for the 2013 season. The Youth Football Surveillance System included 118 youth football teams, providing 4092 athlete-seasons. The National Athletic Treatment, Injury and Outcomes Network program included 96 secondary school football programs, providing 11 957 athlete-seasons. The National Collegiate Athletic Association Injury Surveillance Program included 24 member institutions, providing 4305 athlete-seasons. EXPOSURES: All injuries regardless of severity, including concussions, and athlete exposure information were documented by athletic trainers during practices and games. MAIN OUTCOMES AND MEASURES: Injury rates, injury rate ratios, risks, risk ratios, and 95% CIs were calculated. RESULTS: Concussions comprised 9.6%, 4.0%, and 8.0% of all injuries reported in the Youth Football Surveillance System; National Athletic Treatment, Injury and Outcomes Network; and National Collegiate Athletic Association Injury Surveillance Program, respectively. The game concussion rate was higher than the practice concussion rate across all 3 competitive levels. The game concussion rate for college athletes (3.74 per 1000 athlete exposures) was higher than those for high school athletes (injury rate ratio, 1.86; 95% CI, 1.50-2.31) and youth athletes (injury rate ratio, 1.57; 95% CI, 1.17-2.10). The practice concussion rate in college (0.53 per 1000 athlete exposures) was lower than that in high school (injury rate ratio, 0.80; 95% CI, 0.67-0.96). Youth football had the lowest 1-season concussion risks in 2012 (3.53%) and 2013 (3.13%). The 1-season concussion risk was highest in high school (9.98%) and college (5.54%) in 2012. CONCLUSIONS AND RELEVANCE: Football practices were a major source of concussion at all 3 levels of competition. Concussions during practice might be mitigated and should prompt an evaluation of technique and head impact exposure. Although it is more difficult to change the intensity or conditions of a game, many strategies can be used during practice to limit player-to-player contact and other potentially injurious behaviors.

Injury Rates in Age-Only Versus Age-and-Weight Playing Standard Conditions in American Youth Football.

BACKGROUND: American youth football leagues are typically structured using either age-only (AO) or age-and-weight (AW) playing standard conditions. These playing standard conditions group players by age in the former condition and by a combination of age and weight in the latter condition. However, no study has systematically compared injury risk between these 2 playing standards. PURPOSE: To compare injury rates between youth tackle football players in the AO and AW playing standard conditions. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Athletic trainers evaluated and recorded injuries at each practice and game during the 2012 and 2013 football seasons. Players (age, 5-14 years) were drawn from 13 recreational leagues across 6 states. The sample included 4092 athlete-seasons (AW, 2065; AO, 2027) from 210 teams (AW, 106; O, 104). Injury rate ratios (RRs) with 95% CIs were used to compare the playing standard conditions. Multivariate Poisson regression was used to estimate RRs adjusted for residual effects of age and clustering by team and league. There were 4 endpoints of interest: (1) any injury, (2) non-time loss (NTL) injuries only, (3) time loss (TL) injuries only, and (4) concussions only. RESULTS: Over 2 seasons, the cohort accumulated 1475 injuries and 142,536 athlete-exposures (AEs). The most common injuries were contusions (34.4%), ligament sprains (16.3%), concussions (9.6%), and muscle strains (7.8%). The overall injury rate for both playing standard conditions combined was 10.3 per 1000 AEs (95% CI, 9.8-10.9). The TL injury, NTL injury, and concussion rates in both playing standard conditions combined were 3.1, 7.2, and 1.0 per 1000 AEs, respectively. In multivariate Poisson regression models controlling for age, team, and league, no differences were found between playing standard conditions in the overall injury rate (RRoverall, 1.1; 95% CI, 0.4-2.6). Rates for the other 3 endpoints were also similar (RRNTL, 1.1 [95% CI, 0.4-3.0]; RRTL, 0.9 [95% CI, 0.4-1.9]; RRconcussion, 0.6 [95% CI, 0.3-1.4]). CONCLUSION: For the injury endpoints examined in this study, the injury rates were similar in the AO and AW playing standards. Future research should examine other policies, rules, and behavioral factors that may affect injury risk within youth football.

Acute cardiovascular exercise and executive control function.

Acute cardiovascular exercise effects on cognitive function were examined using an executive control task by comparing neuroelectric and behavioral performance at baseline with post-exercise in 20 undergraduates. A within-subjects design was used to assess the P3 component of an event-related brain potential (ERP) and behavioral performance using a task that varied the amount of executive control required. The baseline session involved participation on the Eriksen flankers task followed by a graded maximal exercise test to measure cardiovascular fitness. The exercise session consisted of a 30-min acute bout of exercise on a treadmill followed by the Eriksen flankers task after heart rate returned to within 10% of pre-exercise levels. Across midline recordings sites, results indicated larger P3 amplitude following acute exercise compared to baseline. Shorter P3 latency was observed during the baseline Eriksen flankers task for the neutral compared to the incompatible condition; an effect not found following the acute bout of exercise. These findings suggest that acute bouts of cardiovascular exercise affect neuroelectric processes underlying executive control through the increased allocation of neuroelectric resources and through changes in cognitive processing and stimulus classification speed.

National collegiate athletic association injury surveillance system: review of methods for 2004-2005 through 2013-2014 data collection.

BACKGROUND: Since 1982, the National Collegiate Athletic Association has used the Injury Surveillance System (ISS) to collect injury and athlete-exposure data from a representative sample of collegiate institutions and sports. At the start of the 2004-2005 academic year, a Web-based ISS replaced the paper-based platform previously used for reporting injuries and exposures. OBJECTIVE: To describe the methods of the Web-based National Collegiate Athletic Association ISS for data collection as implemented from the 2004-2005 to 2013-2014 academic years. DESCRIPTION: The Web-based ISS monitored National Collegiate Athletic Association-sanctioned practices and competitions, the number of participating student-athletes, and time-loss injuries during the preseason, regular season, and postseason in 25 collegiate sports. Starting in the 2009-2010 academic year, non-time-loss injuries were also tracked. Efforts were made to better integrate ISS data collection into the workflow of collegiate athletic trainers. Data for the 2004-2005 to 2013-2014 academic years are available to researchers through a standardized application process available at the Datalys Center Web site. CONCLUSIONS: As of February 2014, more than 1 dozen data sets have been provided to researchers. The Datalys Center encourages applications for access to the data.

Systematic review and meta-analysis of skeletal muscle fatigue in old age.

UNLABELLED: Despite intense interest in understanding how old age may alter skeletal muscle fatigability, a quantitative examination of the impact of study design on age-related differences in muscle fatigue does not exist. PURPOSE: The purpose of this study was to conduct a systematic review of the differences in muscle fatigue between young and older adults, with specific examination of moderator variables suggested to contribute to discrepancies across studies: contraction intensity, contraction mode, duty cycle, fatigue index, sex, muscle group, and contraction type. METHODS: The standardized effect of age on muscle fatigue was computed for 37 studies (60 standardized effects). Standardized effects were coded as positive when less fatigue was reported in older individuals compared with young individuals. RESULTS: The overall standardized effect of age on muscle fatigue was positive (0.56). In studies using dynamic contractions or using muscle power as the index of fatigue, the standardized effect was negative (-0.12 and -2.5, respectively). The standardized effect for all other moderator categories was positive (range = 0.09-0.90), indicating less fatigue in older adults under all other methodological conditions. CONCLUSION: This review provides the first quantitative analysis of the effect of study design on age-related differences in muscle fatigue. The results indicate that older individuals develop less muscle fatigue than young individuals, particularly during isometric contractions of the elbow flexor and knee extensor muscles. However, the results also suggest that older adults develop greater fatigue during dynamic contractions, particularly when the decline in power is assessed. Studies that verify this latter outcome are needed, as are studies designed to elucidate the mechanisms of fatigue.