Head Impact Biomechanics Differ Between Girls and Boys Youth Ice Hockey Players

The influence of sex on head impact biomechanics is unknown for youth ice hockey. We sought to determine sex differences in head impact severity and frequency in youth ice hockey players. Male (n = 110) and female (n = 25) players (13–16 years old) were recruited from a local hockey organization. Players wore helmets instrumented with the Head Impact Telemetry System for all competitions and practices throughout the season. Seven team-seasons were captured. Random intercepts general mixed linear models determined whether linear acceleration and rotational acceleration differed by sex. Linear regression models evaluated the relationship between sex and impact frequency. All head impact biomechanics were natural log-transformed as their distributions were right-skewed. Females sustained fewer impacts per player than males (27 fewer impacts per player-season, p < 0.0001) even when analysis was limited to games only (21 fewer impacts per player-season, p < 0.0001). The linear acceleration was higher among females (1.07 g; 95% CI 1.00, 1.13; p = 0.04). There were no other meaningful sex differences in head impact severity. Female players are not permitted to body check, and this likely explains why they sustain fewer head impacts than males. However, as a result, females likely sustain a higher proportion of head impacts through illegal or unintentional head contact, and these impacts may result in more force being delivered to the head

Evaluating the "threshold Theory": Can Head Impact Indicators Help?

Purpose This study aimed to determine the clinical utility of biomechanical head impact indicators by measuring the sensitivity, specificity, positive predictive value (PV+), and negative predictive value (PV-) of multiple thresholds. Methods Head impact biomechanics (n = 283,348) from 185 football players in one Division I program were collected. A multidisciplinary clinical team independently made concussion diagnoses (n = 24). We dichotomized each impact using diagnosis (yes = 24, no = 283,324) and across a range of plausible impact indicator thresholds (10g increments beginning with a resultant linear head acceleration of 50g and ending with 120g). Results Some thresholds had adequate sensitivity, specificity, and PV-. All thresholds had low PV+, with the best recorded PV+ less than 0.4% when accounting for all head impacts sustained by our sample. Even when conservatively adjusting the frequency of diagnosed concussions by a factor of 5 to account for unreported/undiagnosed injuries, the PV+ of head impact indicators at any threshold was no greater than 1.94%. Conclusions Although specificity and PV- appear high, the low PV+ would generate many unnecessary evaluations if these indicators were the sole diagnostic criteria. The clinical diagnostic value of head impact indicators is considerably questioned by these data. Notwithstanding, valid sensor technologies continue to offer objective data that have been used to improve player safety and reduce injury risk

Fundamentals of Sports Analytics

Recently, the importance of statistics and analytics in sports has increased. This review describes measures of sports injury and fundamentals of sports injury research with a brief overview of some of the emerging measures of sports performance. We describe research study designs that can be used to identify risk factors for injury, injury surveillance programs, and common measures of injury risk and association. Finally, we describe measures of physical performance and training and considerations for using these measures. This review provides sports medicine clinicians with an understanding of current research measures and considerations for designing sports injury research studies

Estimating Concussion Incidence Using Sports Injury Surveillance Systems: Complexities and Potential Pitfalls

Numerous sports injury surveillance systems exist with the capability of tracking concussion incidence data. It is important for the consumers of sport-related concussion data, be they researchers or the public, to have a comprehensive understanding of the strengths and limitations of sports injury surveillance systems. This article discusses issues of system design and analysis that affect the interpretation and understanding of sport-related concussion incidence data from sports injury surveillance systems. Such understanding will help inform the design of sports injury surveillance systems and research studies that aim to identify risk factors, develop prevention strategies, and evaluate prevention mechanisms

High Pressure Thermoelasticity of Body-centered Cubic Tantalum

We have investigated the thermoelasticity of body-centered cubic (bcc) tantalum from first principles by using the linearized augmented plane wave (LAPW) and mixed--basis pseudopotential methods for pressures up to 400 GPa and temperatures up to 10000 K. Electronic excitation contributions to the free energy were included from the band structures, and phonon contributions were included using the particle-in-a-cell (PIC) model. The computed elastic constants agree well with available ultrasonic and diamond anvil cell data at low pressures, and shock data at high pressures. The shear modulus $c_{44}$ and the anisotropy change behavior with increasing pressure around 150 GPa because of an electronic topological transition. We find that the main contribution of temperature to the elastic constants is from the thermal expansivity. The PIC model in conjunction with fast self-consistent techniques is shown to be a tractable approach to studying thermoelasticity.Comment: To be appear in Physical Review

The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school boys' ice hockey (2008-2009 through 2013-2014) and National Collegiate Athletic Association men's and women's ice hockey (2004-2005 through 2013-2014)

Context: Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided efforts to collect data on ice hockey injuries. Objective: To describe the epidemiology of injuries sustained in high school boy's ice hockey in the 2008-2009 through 2013-2014 academic years and collegiate men's and women's ice hockey in the 2004-2005 through 2013-2014 academic years using Web-based surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance of ice hockey teams of high school boys (annual average ¼ 34), collegiate men (annual average ¼ 20), and collegiate women (annual average ¼ 11). Patients or Other Participants: Boys', men's, and women's ice hockey players who participated in practices and competitions during the 2008-2009 through 2013-2014 high school academic years or the 2004-2005 through 2013-2014 collegiate academic years. Main Outcome Measure(s): Athletic trainers collected time-loss (24 hours) injury and exposure data. We calculated injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis. Results: The High School Reporting Information Online system documented 831 boys' ice hockey time-loss injuries during 356 997 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2611 men's ice hockey time-loss injuries during 552 642 AEs and 752 women's ice hockey injuries during 232 051 AEs. Injury rates were higher in collegiate men than in high school boys during 2008-2009 through 2013-2014 (4.38 versus 2.33/1000 AEs; IRR ¼ 1.88; 95% CI ¼ 1.73, 2.05) and collegiate women during 2004-2005 through 2013-2014 (IRR ¼ 1.46; 95% CI ¼ 1.34, 1.58). Most injuries occurred during competitions (boys ¼ 80.0%, men ¼ 66.9%, women ¼ 55.3%); injury rates were higher in competitions than in practices for boys (IRR ¼ 8.14; 95% CI ¼ 6.87, 9.65), men (IRR ¼ 6.58; 95% CI ¼ 6.06, 7.13), and women (IRR ¼ 3.63; 95% CI ¼ 3.14, 4.19). At all levels, most injuries occurred to the head/face and shoulder/clavicle and resulted in concussions, contusions, or ligament sprains. Conclusions: Injury rates varied across sports but were consistently higher in competitions than in practices. In competitions, concussions were common injuries, highlighting the need for continued development of injury-prevention strategies

The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in us high school girls' volleyball (2005-2006 through 2013-2014) and national collegiate athletic association women's volleyball (2004-2005 Through 2013-2014)

Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided in the acquisition of girls' and women's volleyball injury data. Objective: To describe the epidemiology of injuries sustained in high school girls' volleyball in the 2005-2006 through 2013-2014 academic years and collegiate women's volleyball in the 2004-2005 through 2013-2014 academic years using Webbased sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from high school girls' (annual average=100) and collegiate women's (annual average = 50) volleyball teams. Patients or Other Participants: Girls' and women's volleyball players who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school and the 2004-2005 through 2013-2014 academic years in college. Main Outcome Measure(s): Athletic trainers collected timeloss (≥24 hours) injury and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis were calculated. Results: The High School Reporting Information Online system documented 1634 time-loss injuries during 1 471 872 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2149 time-loss injuries during 563 845 AEs. The injury ratewas higher in college than in high school (3.81/ 1000 versus 1.11/1000 AEs; IRR=3.43; 95%CI=3.22, 3.66), and higher in high schools with ≤1000 students than in those with >1000 students (IRR=1.35; 95% CI=1.23, 1.49). Injury rates did not vary by collegiate division. The injury rate was higher during competitions than practices for high school (IRR=1.23; 95% CI= 1.12, 1.36) but not for college (IRR= 1.01; 95% CI= 0.92, 1.10). Ankle sprains were common in both the high school and collegiate setting. However, liberos had a high incidence of concussion. Conclusions: Injury rates were higher among collegiate than high school players. However, injury rates differed by event type in high school, unlike college. Concussion injury patterns among liberos varied from those for other positions. These findings highlight the need for injury-prevention interventions specific to setting and position

The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school boys' wrestling (2005-2006 through 2013-2014) and National Collegiate Athletic Association Men's Wrestling (2004-2005 through 2013-2014)

Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of wrestling injury data. Objective: To describe the epidemiology of injuries sustained in high school boys' wrestling in the 2005-2006 through 2013-2014 academic years and collegiate men's wrestling in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from wrestling teams of high school boys (annual average ¼ 100) and collegiate men (annual average ¼ 11). Patients or Other Participants: Male wrestlers who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school or the 2004-2005 through 2013-2014 academic years in college. Main Outcome Measure(s): Athletic trainers collected time-loss (24 hours) injuries and exposure data during this time period. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios with 95% confidence intervals, and injury proportions by body site and diagnosis were calculated. Results: The High School Reporting Information Online documented 3376 time-loss injuries during 1 416 314 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2387 time-loss injuries during 257 297 AEs. The total injury rate was higher in college than in high school (9.28 versus 2.38/1000 AEs; injury rate ratio ¼ 3.89; 95% confidence interval ¼ 3.69, 4.10). In high school, the most commonly injured body parts for both practices and competitions were the head/face (practices ¼ 19.9%, competitions ¼ 21.4%) and shoulder/clavicle (practices ¼ 14.1%, competitions ¼ 21.0%). In college, the most frequently injured body parts for both practices and competitions were the knee (practices ¼ 16.7%, competitions ¼ 30.4%) and head/face (practices ¼ 12.1%, competitions ¼ 14.6%). Conclusions: Injury rates were higher in collegiate than in high school players, and the types of injuries sustained most often differed. Based on these results, continued study of primary and secondary prevention of injury in wrestlers across levels of competition is warranted

The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in United States high school football (2005-2006 through 2013-2014) and National collegiate athletic association football (2004-2005 through 2013-2014)

Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of football injury data. Objective: To describe the epidemiology of injuries sustained in high school football in the 2005-2006 through 2013-2014 academic years and collegiate football in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from football teams of high school boys (annual average ¼ 100) and collegiate men (annual average ¼ 43). Patients or Other Participants: Football players who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school or the 2004-2005 through 2013-2014 academic years in college. Main Outcome Measure(s): Athletic trainers collected time-loss injury (24 hours) and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis were calculated. Results: The High School Reporting Information Online system documented 18 189 time-loss injuries during 4 539 636 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 22 766 time-loss injuries during 3 121 476 AEs. The injury rate was higher among collegiate than high school (7.29 versus 4.01/1000 AEs; IRR ¼ 1.82; 95% CI ¼ 1.79, 1.86) athletes. Most injuries occurred during competitions in high school (53.2%) and practices in college (60.9%). The competition injury rate was higher than the practice injury rate among both high school (IRR ¼ 5.62; 95% CI ¼ 5.46, 5.78) and collegiate (IRR ¼ 6.59; 95% CI ¼ 6.41, 6.76) players. Most injuries at both levels affected the lower extremity and the shoulder/clavicle and were diagnosed as ligament sprains and muscle/tendon strains. However, concussion was a common injury during competitions among most positions. Conclusions: Injury rates were higher in college than in high school and higher for competitions than for practices. Concussion was a frequent injury sustained during competitions, which confirms the need to develop interventions to mitigate its incidence and severity

The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school girls’ softball (2005–2006 through 2013–2014) and National Collegiate Athletic Association women’s softball (2004–2005 through 2013–2014)

Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of girls’ and women’s softball injury data. Objective: To describe the epidemiology of injuries sustained in high school girls’ softball in the 2005–2006 through 2013–2014 academic years and collegiate women’s softball in the 2004–2005 through 2013–2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from softball teams in high school girls (annual average ¼ 100) and collegiate women (annual average ¼ 41). Patients or Other Participants: Girls’ or women’s softball players who participated in practices and competitions during the 2005–2006 through 2013–2014 academic years in high school and the 2004–2005 through 2013–2014 academic years in college. Main Outcome Measure(s): Athletic trainers collected time-loss injury and exposure data. Injury rates per 1000 athlete-exposures (AEs) were calculated. Injury rate ratios (IRRs) with 95% confidence intervals (CIs) compared injury rates by competition level, school size or division, event type, and time in season. Results: The High School Reporting Information Online system documented 1357 time-loss injuries during 1 173 722 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 1848 time-loss injuries during 579 553 AEs. The injury rate was higher in college than in high school (3.19 versus 1.16/1000 AEs; IRR ¼ 2.76; 95% CI ¼ 2.57, 2.96). The competition injury rate was higher than the practice injury rate in high school (IRR ¼ 2.02; 95% CI ¼ 1.82, 2.25) and in college (IRR ¼ 1.39; 95% CI ¼ 1.27, 1.52). Softball players at both levels sustained a variety of injuries, with the most common being ankle sprains and concussions. Many injuries also occurred while fielding or running bases. Conclusions: Injury rates were greater in collegiate versus high school softball and in competitions versus practices. These findings highlight the need for injury-prevention interventions, including strength-training and prevention programs to reduce ankle sprains and provide protection for batters from pitches and fielders from batted balls