Comparison of Concussion Rates Between NCAA Division I and Division III Men's and Women's Ice Hockey Players

The Role of Level of Play in Concussions in High School Athletes

OBJECTIVES

To examine level of play (LOP) as a risk factor for concussion severity and recovery-related outcomes among high school athletes, stratified by sex, and among boys, by sport (football, non-football male sports).

DESIGN/SETTING

Secondary analysis of data collected through the High School Reporting Information Online surveillance system for academic years 2007-2008 through 2018-2019.

PARTICIPANTS

A total of 9916 concussions were reported between the academic years 2007-2008 and 2018-2019 from 9 sports (5189 from football; 2096 from non-football male sports; 2631 from female sports).

MAIN OUTCOME MEASURE

Examined the association between LOP (Freshman, Junior Varsity [JV], and Varsity teams) and concussion outcomes (number of concussion symptoms, symptom resolution time [SRT], and time to return to play [RTP]).

RESULTS

Compared with Varsity football athletes, concussed JV football athletes had on average 0.19 fewer concussion symptoms, longer SRT (>1 week vs <1 week: odds ratio [OR] = 1.3; 95% confidence interval [CI], 1.1-1.5), and longer RTP (1-3 weeks vs <1 week: OR = 1.5; 95% CI, 1.2-1.9; >3 weeks vs <1 week: OR = 1.6; 95% CI, 1.1-2.3). Compared with Varsity football athletes, Freshman football athletes had on average 0.48 fewer concussion symptoms, longer SRT (OR = 1.3; 95% CI, 1.1-1.5), and longer RTP (1-3 weeks vs <1 week: OR = 1.5; 95% CI, 1.1-2.0; >3 weeks vs <1 week: OR = 2.0; 95% CI, 1.3-3.0). Similarly, compared with female athletes on Varsity teams, concussed JV female athletes had longer RTP (1-3 weeks vs <1 week: OR = 1.8; 95% CI, 1.2-2.7). Trend analyses revealed an increase in the number of concussion symptoms between 2015-2016 and 2018-2019, a decrease between 2009-2010 and 2018-2019 for SRT of less than 1 week, and an increase between 2014-2015 and 2018-2019 for RTP of less than 1 week among Varsity football athletes. Among Varsity female athletes, there was a linear decrease during the study period for RTP of less than 1 week.

CONCLUSIONS

Despite a higher number of symptoms overall and in recent years, Varsity football players had shorter RTP than Freshman and JV athletes.

Injury patterns in Swedish elite female and male ice hockey - A cross-sectional comparison of past-season's injuries

OBJECTIVES

To describe and compare seasonal prevalence, anatomical location, severity, and onset of injuries between female and male elite ice hockey players.

DESIGN

Cross-sectional survey study.

SETTING

Elite ice hockey.

PARTICIPANTS

Swedish elite ice hockey players (170 females & 190 males).

MAIN OUTCOME MEASURES

Past season injuries reported on a modified version of the Oslo Sports Trauma Research Center overuse injury questionnaire. Proportions of players who experienced any and substantial problems, as well as respective injury severity scores were presented and compared between sexes.

RESULTS

Highest seasonal prevalence was reported for hip/groin [31.1% (n = 112)], lower back [24.2% (n = 87)], and shoulder injuries [23.6% (n = 85)]. Prevalence of injuries was approximately similar between sexes. Substantial injuries were most prevalent in the hip/groin (13.3% [n = 48]) and knee (18.6% [n = 67]) region. Females reported a higher proportion of substantial hip/groin injuries. Most reported injuries were acute except for hip/groin and lower back injuries (74.4% and 81.8% due to overuse).

CONCLUSION

Seasonal prevalence of injuries in elite ice hockey players were comparable between sexes. Acute injuries were most common but hip/groin as well as lower back injuries were predominantly due to overuse. The highest reported prevalence was found for hip and groin-, lower back-, and shoulder injuries.

The effect of specialization and level of competition on injury in elite male ice hockey players

OBJECTIVE

Young players experience pressure to focus on ice hockey at the exclusion of other sports in order to improve chances of success. Early specialization in other sports has been associated with increased injury without the benefit of improved success. The objective of the current study was to investigate whether earlier specialization results in increased injury without higher rates of career success. This study also aimed to compare rates of injury in athletes at various levels of competition.

METHODS

An original survey was issued to men's ice hockey players at the juniorA, collegiate, and professional levels. The survey consisted of 34 questions on various demographic, specialization, and injury variables. All participants were >18 years of age.

RESULTS

The survey was completed by 101 athletes. The mean age at specialization was 13 (±4) overall and 14 (±3), 13 (±4), and 11(±4) for professional, collegiate, and junior players, respectively. There was no difference in age at specialization between each group and professional players did not specialize earlier than the remainder of the cohort as a whole (p > 0.05). There was no significant correlation between age at specialization and total injuries (p > 0.05). There was no difference in concussions causing missed play time between groups (p > 0.05) but professional players had more overall concussions and underwent more surgeries due to hockey-related injuries (p = 0.01).

CONCLUSIONS

Specializing exclusively in ice hockey earlier in life was not associated with playing professionally. Both collegiate and professional players do not tend to specialize prior to age 12. Age at specialization was not associated with overall number of injuries. Professional players with longer careers appear to sustain more concussions and undergo more surgery.

Parent influence on concussion reporting in first-year collegiate athletes

OBJECTIVE

To assess the relationship between sport-parenting practices and concussion reporting intentions of collegiate athletes across two levels of competition.

PARTICIPANTS

Entering first-year student-athletes (varsity and club) at a mid-sized university in the Southeast region of the United States (n = 327).

METHODS

Written surveys were completed prior to the start of the 2015 academic year. Structural equation modeling was used to test a model predicting concussion-reporting intentions.

RESULTS

College athletes were more likely to intend to report a suspected concussion when they believed their parents wanted them to report (B=-0.88, SD = 0.94), and when they experienced less sport achievement pressure from their parents (B=-0.12, SD = 8.07).

CONCLUSIONS

Parents influence the concussion safety of entering collegiate athletes at both the varsity and club level. Lower pressure sport parenting prior to college entry may help foster safer concussion reporting behaviors and may be an appropriate target for future intervention development work.

Sex Differences in Neck Strength Force and Activation Patterns in Collegiate Contact Sport

The purpose of this study was to assess changes in cervical musculature throughout contact-heavy collegiate ice hockey practices during a regular season of NCAA Division III ice hockey teams. In this cross-sectional study, 36 (male n = 13; female n = 23) ice hockey players participated. Data were collected over 3 testing sessions (baseline; pre-practice; post-practice). Neck circumference, neck length, head-neck segment length, isometric strength and electromyography (EMG) activity for flexion and extension were assessed. Assessments were completed approximately 1h before a contact-heavy practice and 15 min after practice. For sternocleidomastoid (SCM) muscles, males had significantly greater peak force and greater time to peak force versus females. For both left and right SCMs, both sexes had significantly greater peak EMG activity pre-practice versus baseline, and right (dominant side) SCM time to peak EMG activity was decreased post-practice compared to pre-practice. There were no significant differences for EMG activity of the upper trapezius musculature, over time or between sexes. Sex differences observed in SCM force and activation patterns of the dominant side SCM may contribute to head stabilization during head impacts. Our study is the first investigation to report changes in cervical muscle strength in men's and women's ice hockey players in the practical setting.

Epidemiology of Concussions in National Collegiate Athletic Association (NCAA) Sports: 2014/15-2018/19

BACKGROUND

Updated epidemiology studies examining sports-related concussions (SRCs) are critical in evaluating recent efforts aimed at reducing the incidence of SRCs in National Collegiate Athletic Association (NCAA) sports.

PURPOSE

To describe the epidemiology of SRCs in 23 NCAA sports during the 2014/15-2018/19 academic years.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

SRC and exposure data collected in the NCAA Injury Surveillance Program were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics by sport, event type (practices, competitions), injury mechanism (player contact, surface contact, equipment/apparatus contact), and injury history (new, recurrent). Injury rate ratios (IRRs) were used to examine differential injury rates, and injury proportion ratios (IPRs) were used to examine differential distributions.

RESULTS

A total of 3497 SRCs from 8,474,400 athlete-exposures (AEs) were reported during the study period (4.13 per 10,000 AEs); the competition-related SRC rate was higher than was the practice-related SRC rate (IRR, 4.12; 95% CI, 3.86-4.41). The highest SRC rates were observed in men's ice hockey (7.35 per 10,000 AEs) and women's soccer (7.15 per 10,000 AEs); rates in women's soccer and volleyball increased during 2015/16-2018/19. Player contact was the most prevalently reported mechanism in men's sports (77.0%), whereas equipment/apparatus contact was the most prevalently reported mechanism in women's sports (39.2%). Sex-related differences were observed in soccer, basketball, softball/baseball, and swimming and diving. Most SRCs reported in men's sports (84.3%) and women's sports (81.1%) were reported as new injuries.

CONCLUSION

Given the increasing SRC rates observed in women's soccer and volleyball during the latter years of the study, these results indicate the need to direct further attention toward trajectories of SRC incidence in these sports. The prevalence of equipment/apparatus contact SRCs in women's sports also suggests that SRC mechanisms in women's sports warrant further investigation. As most SRCs during the study period were reported as new injuries, the prevalence of recurrent SRCs in men's and women's ice hockey is also noteworthy.

Multiple Past Concussions in High School Hockey Players: Examining Cognitive Functioning and Symptom Reporting

OBJECTIVE

To investigate (1) if there are meaningful differences in baseline preseason cognitive functioning or symptom reporting between high school ice hockey players with and without prior concussions and (2) determine which health history variables predict symptom reporting.

DESIGN

Cross-sectional study.

SETTING

High schools across the state of Maine.

PARTICIPANTS

Participants were 1616 male high school ice hockey players (mean age = 15.6 years; SD = 1.5 years) who completed baseline testing between 2009 and 2015.

INDEPENDENT VARIABLES

Athletes were grouped according to their self-reported concussion history [0 (n = 1136), 1 (n = 321), 2 (n = 112), or 3+ (n = 47) previous concussions].

MAIN OUTCOME MEASURES

Cognitive functioning was measured by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery, and symptom ratings were obtained from the Post-Concussion Symptom Scale.

RESULTS

There were no statistically significant differences between groups in cognitive functioning as measured by ImPACT. The group with ≥3 prior concussions endorsed higher total symptom scores, but the effect sizes were small and not statistically significant. In a multivariate model, prior treatment for headaches (not necessarily migraines), prior treatment for a psychiatric condition, and prior treatment for substance/alcohol use all significantly predicted total symptom scores, with concussion history being the weakest independent predictor.

CONCLUSIONS

Players with a history of prior concussions performed similarly to players with no prior concussions on cognitive testing. Health history factors were more strongly associated with symptom reporting than concussion history.

Epidemiology of Injuries in National Collegiate Athletic Association Women's Ice Hockey: 2014-2015 Through 2018-2019

CONTEXT

The National Collegiate Athletic Association (NCAA) has sponsored women's ice hockey championships since 2001, and sponsorship has grown over time.

BACKGROUND

Routine examinations of injuries sustained by athletes are important for identifying and understanding patterns that can be used to inform sport safety practices.

METHODS

Exposure and injury data collected in the NCAA Injury Surveillance Program from 2014-2015 through 2018-2019 were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differential injury rates.

RESULTS

The overall injury rate was 5.89 per 1000 athlete-exposures; preseason injury incidence rose sharply during 2016-2017 through 2018-2019. Head/face injuries (15.2%), knee injuries (13.2%), and shoulder injuries (12.9%) were the most commonly injured body parts, and injuries were most often classified as contusions (18.9%), strains (18.7%), and sprains (15.5%). Concussion (11.9%) was the most commonly reported specific injury, and concussion rates notably increased during 2017-2018 through 2018-2019.

SUMMARY

Study findings were generally consistent with the existing epidemiological evidence. Injury incidence in preseason and the etiology of strains warrant further attention in this population.

Epidemiology of NCAA Bone Stress Injuries: A Comparison of Athletes in Divisions I, II, and III

Background:

Bone stress injuries (BSIs) are a major source of functional impairment in athletes of all sports, with many risk factors, including athlete characteristics and type of sport. In National Collegiate Athletic Association (NCAA) athletics, the stratification of programs into divisions with different characteristics and makeup has been identified as increasing the risk for certain kinds of injuries, but there have been no studies on the difference of BSI rates and characteristics between athletes in Division I (DI) and those in Divisions II and III (DII and DIII).

Purpose/Hypothesis:

To characterize the BSI rates in each division and compare the incidence and characteristics of BSIs within divisions. Our hypothesis was that BSI rates would be higher in DII and DIII athletes as compared with DI athletes.

Study Design:

Descriptive epidemiology study.

Methods:

Five years of recorded BSI data in collegiate athletes via the NCAA Injury Surveillance Program were examined for the academic years 2009-2010 to 2013-2014. BSI rates per 100,000 athlete-exposures (AEs) were compared for DI versus DII and DIII athletes using risk ratios and 95% CIs. Time lost to injury, time of season of injury, and class composition of injured athletes were also compared between divisions.

Results:

Over the 5 years studied, DII and DIII programs reported 252 BSIs more than 1,793,777 AEs (14.05 per 100,000 AEs), and DI programs reported 235 BSIs over 2,022,592 AEs (11.62 per 100,000 AEs). The risk ratio was significant for D1 versus DII and DIII (1.21; 95% CI, 1.01-1.44). There was a significant difference in time lost to injury in DI versus DII and DIII, χ²(5, n = 449) = 16.54; P = .006. When data were stratified by individual sport, there were no significant divisional differences in high-risk sports.

Conclusion:

In the current study, NCAA DII and DIII athletes had higher rates of BSI than their DI counterparts. As compared with DII and DIII athletes, the DI athletes had a significantly greater proportion of BSIs that did not result in absence from participation in sport.

An Examination of Perceived Pressure From Stakeholders on Concussion Reporting Intentions and Behavior in Ice Hockey Athletes

OBJECTIVE

We aimed to assess whether perceived pressure predicts concussion reporting intentions and behavior in youth, high school, and collegiate ice hockey athletes, and, secondarily, whether perceived pressure from stakeholders differed between sex or level of play.

SETTING

Online survey.

PARTICIPANTS

One hundred fifty-two ice hockey athletes (males: n = 96, 63.2%; females: n = 55, 36.2%; missing: n = 1, 0.7%; age = 14.04 ± 3.6 years).

DESIGN

Cross-sectional.

MAIN MEASURES

Respondents answered a survey that elicited information about demography, perceived pressure from 6 stakeholders, and concussion reporting intentions and behavior. For the first aim, we used a generalized linear model to determine whether perceived pressure from any stakeholder predicted intention (symptom reporting, concussion reporting, and intention beliefs) or behavior ("all concussions," "not obvious concussions"; α < .05) while controlling for level of play. To determine whether pressure from any stakeholder predicted symptom reporting behavior, we used logistic regression while controlling for level of play. For the second aim, to examine sex differences in perceived pressure from each stakeholder, we employed Mann-Whitney tests and to examine level of play differences, we used Kruskal-Wallis tests.

RESULTS

Controlling for level of play, a 1-point increase in perceived pressure from parents and athletic administrators decreased concussion reporting intentions by 0.92 (P = .004) and 1.09 (P = .005) points, respectively. Perceived pressure from a sports medicine professional decreased intention beliefs by 0.17 (P = .029) points. Perceived pressure from stakeholders did not predict symptom reporting (P = .440) or "not obvious concussion" reporting (P = .655) behavior. We observed no difference in perceived pressure across stakeholders (all P values >.05); however, collegiate ice hockey respondents perceived greater pressure from coaches than youth or high school athletes (P < .001). We noted no other differences in perceived pressure across levels of play (all P values >.05).

CONCLUSIONS

Concussion reporting intentions were negatively influenced by perceived pressure from parents, athletic administrators, and sports medicine professionals, but these findings did not translate to reporting behavior.

Data-Driven Risk Classification of Concussion Rates: A Systematic Review and Meta-Analysis

BACKGROUND

Concussion is a growing public health concern and generating concussion prevention programs depends on identifying high-risk sports and characteristics. Identifying the roles of sport, sex, and participation level (e.g., high school versus collegiate athletics) in concussion risk would facilitate more informed decision-making regarding sports participation and generate better targeted prevention strategies.

OBJECTIVES

The current study's objectives were to: (1) determine the magnitude and hierarchy of sports-related concussion (SRC) risk across an array of events and (2) evaluate the modifying roles of sex, participation level, and session type on SRC rates.

METHODS

A literature search was conducted on PubMed, searching concussion studies published between 2001 and December 2019. Inclusion criteria for studies required: (1) concussion occurred during sport, (2) that the SRC was clinically diagnosed, and (3) athlete exposures and concussions could be extracted or estimated. A study was excluded if it: (1) was not an original research article, (2) was not written in English language, (3) was an animal study, (4) did not have enough data to calculate SRC rates, (5) included professional or youth sample, and/or (6) contained data collected prior to 2001. The meta-analysis and meta-regression analyses were fit using a random effects model.

RESULTS

Search results returned 2695 unique research articles, with 83 studies included in analyses. Sport, sex, participation level, and session type all significantly influenced SRC rates. Overall, rugby had the highest concussion rate and was classified as the highest risk sport (28.25 concussions per 10,000 athlete exposures). Overall, females had a higher concussion rate than males. Only lacrosse demonstrated a higher concussion rate for males compared to females. Collegiate athletes had higher concussion rates than high school athletes. Games were associated with 2.01 more concussions per 10,000 AEs than practices.

CONCLUSIONS

This meta-analysis demonstrated rugby has the highest concussion risk, followed by American Football, ice hockey, and wrestling. Concussion risk was influenced by sport, sex, participation, and session. Identifying the factors and environments that influence concussion risk can facilitate risk reduction and prevention strategies.

Detailed description of Division I ice hockey concussions: Findings from the NCAA and Department of Defense CARE Consortium

OBJECTIVE

Since concussion is the most common injury in ice hockey, the objective of the current study was to elucidate risk factors, specific mechanisms, and clinical presentations of concussion in men's and women's ice hockey.

METHODS

Ice hockey players from 5 institutions participating in the Concussion Assessment, Research, and Education Consortium were eligible for the current study. Participants who sustained a concussion outside of this sport were excluded. There were 332 (250 males, 82 females) athletes who participated in ice hockey, and 47 (36 males, 11 females) who sustained a concussion.

RESULTS

Previous concussion (odds ratio (OR) = 2.00; 95% confidence interval (95% CI): 1.02‒3.91) was associated with increased incident concussion odds, while wearing a mouthguard was protective against incident concussion (OR = 0.43; 95%CI: 0.22‒0.85). Overall, concussion mechanisms did not significantly differ between sexes. There were specific differences in how concussions presented clinically across male and female ice hockey players, however. Females (9.09%) were less likely than males (41.67%) to have a delayed symptom onset (p = 0.045). Additionally, females took significantly longer to reach asymptomatic (p = 0.015) and return-to-play clearance (p = 0.005). Within the first 2 weeks post-concussion, 86.11% of males reached asymptomatic, while only 45.50% of females reached the same phase of recovery. Most males (91.67%) were cleared for return to play within 3 weeks of their concussion, compared to less than half (45.50%) of females.

CONCLUSION

The current study proposes possible risk factors, mechanisms, and clinical profiles to be validated in future concussions studies with larger female sample sizes. Understanding specific risk factors, concussion mechanisms, and clinical profiles of concussion in collegiate ice hockey may generate ideas for future concussion prevention or intervention studies.

Unexpected Findings from a Pilot Study on Vision Training as a Potential Intervention to Reduce Subconcussive Head Impacts during a Collegiate Ice Hockey Season

Player-to-player contact is the most frequent head impact mechanism in collegiate ice hockey. Training with three-dimensional multiple-object tracking (3D-MOT) could potentially reduce the quantity and severity of head impacts by enhancing player anticipation of these impacts. The purpose of this study was to evaluate the efficacy of 3D-MOT training to reduce the numbers of head impacts sustained by National Collegiate Athletic Association Division III men's and women's ice hockey players. Collegiate men's and women's ice hockey players (N = 33; men = 17, women = 16) were randomly assigned to a 3D-MOT group (n = 17) or a control (C) group (n = 16). Head impacts were monitored during practices and games, and 3D-MOT training occurred twice per week for 12 weeks throughout one regular season. 3D-MOT forwards sustained head impacts with greater mean peak linear acceleration (3D-MOT = 41.33 ± 28.54 g; C = 38.03 ± 24.30 g) and mean peak rotational velocity (3D-MOT = 13.59 ± 8.18 rad^.sec^-1; C = 12.47 ± 7.69 rad^.sec^-1) in games, and greater mean peak rotational velocity in practices versus C forwards (3D-MOT = 11.96 ± 6.77 rad^.sec^-1; C = 10.22 ± 6.95 rad^.sec^-1). Conversely, 3D-MOT defensemen sustained head impacts with a mean peak rotational velocity less than that of C defensemen (3D-MOT = 11.54 ± 6.76 rad^.sec^-1; C = 13.65 ± 8.43 rad^.sec^-1). There was no significant difference for all other parameters analyzed between 3D-MOT and C groups. Player position may play an important role in future interventions to reduce head impacts in collegiate ice hockey.

Considering Biological Sex in Traumatic Brain Injury

Published epidemiological studies of traumatic brain injury (TBI) of all severities consistently report higher incidence in men. Recent increases in the participation of women in sports and active military service as well as increasing awareness of the very large number of women who sustain but do not report TBI as a result of intimate partner violence (IPV) suggest that the number of women with TBI is significantly larger than previously believed. Women are also grossly under-represented in clinical and natural history studies of TBI, most of which include relatively small numbers of women, ignore the role of sex- and age-related gonadal hormone levels, and report conflicting results. The emerging picture from recent studies powered to detect effects of biological sex as well as age (as a surrogate of hormonal status) suggest young (i.e., premenopausal) women are more likely to die from TBI relative to men of the same age group, but this is reversed in the 6th and 7th decades of life, coinciding with postmenopausal status in women. New data from concussion studies in young male and female athletes extend this finding to mild TBI, since female athletes who sustained mild TBI are significantly more likely to report more symptoms than males. Studies including information on gonadal hormone status at the time of injury are still too scarce and small to draw reliable conclusions, so there is an urgent need to include biological sex and gonadal hormone status in the design and analysis of future studies of TBI.

Epidemiology of Concussions in High School Boys' Ice Hockey, 2008/09 to 2016/17 School Years

OBJECTIVE

This study examined the epidemiology of concussions in high school boys' ice hockey during the 2008/09 to 2016/17 school years.

DESIGN

Prospective cohort study. Athletic trainers from an average 33 high schools annually reported boys' ice hockey concussion and athlete-exposure (AE) data for the High School Reporting Information Online system.

SETTING

Convenience sample of high school boys' ice hockey programs during the 2008/09 to 2016/17 school years.

PATIENTS OR OTHER PARTICIPANTS

High school boys' ice hockey players (aged ∼14-18 years).

INDEPENDENT VARIABLES

Concussion data on event type, injury mechanism, symptom resolution time, and time loss were obtained.

MAIN OUTCOME MEASURES

Concussion rates with 95% confidence intervals (CIs) and distributions were calculated.

RESULTS

Overall, 348 concussions were reported in boys' ice hockey during the 2008/09 to 2016/17 academic years, leading to a concussion rate of 0.68/1000 AEs (95% CI, 0.61-0.75). Most occurred in competitions (85.6%), particularly after the first period (72.1% of all competition concussions). Among practice concussions, most occurred after the first hour of practice (60.0%). Most concussions were due to player contact (47.7%) and boards/glass contact (31.9%). Although 69.0% of concussed athletes had symptoms resolve in less than 7 days, only 14.1% returned to activity within a week.

CONCLUSIONS

Most concussions occurred within the second and third periods. Preventive strategies that counter an increased risk of concussion due to a greater intensity of gameplay coupled with increased fatigue may be warranted. Moreover, athletes may further benefit from prevention efforts that focus on anticipating impacts during gameplay.

Differences in sport-related concussion for female and male athletes in comparable collegiate sports: a study from the NCAA-DoD Concussion Assessment, Research and Education (CARE) Consortium

OBJECTIVES

To examine sex differences in sport-related concussion (SRC) across comparable sports.

METHODS

Prospective cohort of collegiate athletes enrolled between 2014 and 2017 in the Concussion Assessment, Research and Education Consortium study.

RESULTS

Among 1071 concussions (females=615; 57.4%), there was no difference in recovery (median days to full return to play) (females=13.5 (IQR 9.0, 23.1) vs males=11.8 (IQR 8.1, 19.0), p=0.96). In subgroup analyses, female recovery was longer in contact (females=12.7 days (IQR 8.8, 21.4) vs males=11.0 days (IQR 7.9, 16.2), p=0.0021), while male recovery was longer in limited contact sports (males=16.9 days (IQR 9.7, 101.7) vs females=13.8 days (IQR 9.1, 22.0), p<0.0001). There was no overall difference in recovery among Division I schools (females=13.7 (IQR 9.0, 23.1) vs males=12.2 (IQR 8.2 19.7), p=0.5), but females had longer recovery at the Division II/III levels (females=13.0 (IQR 9.2, 22.7) vs males=10.6 (IQR 8.1, 13.9), p=0.0048).

CONCLUSION

Overall, no difference in recovery between sexes across comparable women's and men's sports in this collegiate cohort was found. However, females in contact and males in limited contact sports experienced longer recovery times, while females had longer recovery times at the Division II/III level. These disparate outcomes indicate that, while intrinsic biological sex differences in concussion recovery may exist, important, modifiable extrinsic factors may play a role in concussion outcomes.

Women Are at Higher Risk for Concussions Due to Ball or Equipment Contact in Soccer and Lacrosse

BACKGROUND

There is ample evidence to suggest sex- and gender-based differences in the incidence of sports-related concussions. The mechanisms of concussion may vary between male and female athletes and contribute to this observed difference. Understanding the underlying etiology by pooling data from primary studies across different settings and sport types will inform interventions that can reduce concussion rates.

QUESTIONS/PURPOSES

Specifically, we asked: (1) In which sports are female athletes less likely to experience concussions from player contact? (2) In which sports are female athletes more likely to experience concussions because of ball or equipment contact?

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched to identify articles published from January 2000 to December 2018. Ten studies met the inclusion criteria, which were studies that reported concussion incidence by mechanism for both male and female athletes. Exclusion criteria included non-English studies, conference abstracts, and studies on non-sports related concussions. The sports represented by the 10 studies included ice hockey (n = 4), soccer (n = 5), basketball (n = 4), baseball/softball (n = 4), and lacrosse (n = 5). The rate ratio was calculated as the incidence rate in female athletes/male athletes for each concussion mechanism or activity. Data were pooled using the DerSimonian-Laird random-effects model. Study quality was assessed with the Newcastle-Ottawa Scale.

RESULTS

Female athletes were at lower risk of player-contact-induced concussions in lacrosse (pooled rate ratio 0.33 [95% CI 0.25 to 0.43]; p < 0.001), basketball (pooled rate ratio 0.86 [95% CI 0.76 to 0.97]; p = 0.01), ice hockey (pooled rate ratio 0.64 [95% CI 0.56 to 0.73]; p < 0.001), soccer (pooled rate ratio 0.70 [95% CI 0.66 to 0.75]; p < 0.001), and soccer heading (pooled rate ratio 0.80 [95% CI 0.72 to 0.90]; p < 0.001); in these sports, men were at higher risk of concussions from player contact. Female athletes were more likely to experience concussions because of ball or equipment contact in lacrosse (pooled rate ratio 3.24 [95% CI 2.10 to 4.99]; p < 0.001), soccer (pooled rate ratio 2.04 [95% CI 1.67 to 2.49]; p < 0.001), and soccer heading (pooled rate ratio 2.63 [95% CI 1.84 to 3.77]; p < 0.001).

CONCLUSIONS

The mechanism or activity underlying concussions differs between male and female athletes across different sports. This finding remains the same regardless of whether there are rule differences between the men's and women's games. The implementation of other interventions are required to further ensure player safety, including protective head equipment, concussion prevention training, or rules limiting player contact in the men's game.

LEVEL OF EVIDENCE

Level III, retrospective study.

The Epidemiology of Sport-Related Concussion: What the Rehabilitation Clinician Needs to Know

Sport-related concussion is common in full-contact and collision sports. Epidemiology studies use different types of surveillance systems and concussion definitions. Concussion incidence rates vary across age, sex, sport, and level of competition. Incidence rates are increasing, likely due to higher rates of reporting following improved knowledge and increased regulations. In this review, we summarize 7 key concepts related to concussion epidemiology: concussion definition, changes in concussion knowledge, reliability and accuracy of injury surveillance systems, conservative management and return to play, reliability of self-report, incidence of concussion across levels of play, and understanding the behaviors of players, coaches, and medical personnel from a multidisciplinary management perspective. J Orthop Sports Phys Ther 2019;49(11):768-778. doi:10.2519/jospt.2019.9105.

Sex-Based Differences in the Incidence of Sports-Related Concussion: Systematic Review and Meta-analysis

CONTEXT

The incidence of sports-related concussion in females has been increasing in recent years.

OBJECTIVE

To conduct a meta-analysis on sex-based differences in concussion incidence in various sports and to determine the effects of study design (retrospective vs prospective), setting (competition vs practice), and population (university and above vs high school and below) via a meta-regression.

DATA SOURCES

PubMed (Medline), EMBASE, and Cochrane Library databases were searched from January 2000 to January 2018.

STUDY SELECTION

Studies reporting sports-related concussion incidence data for both males and females (age ≥10 years) were included.

STUDY DESIGN

Systematic review with meta-analysis and meta-regression.

LEVEL OF EVIDENCE

Level 4.

METHODS

The rate ratio was calculated as the concussion rate in females/males. Data were pooled using the DerSimonian-Laird random-effects model.

RESULTS

Thirty-eight studies met the eligibility criteria and were included in the meta-analysis. Soccer and basketball demonstrated significantly higher incidence of concussions in females compared with males (rate ratio [95% CI], 1.76 [1.43-2.16] and 1.99 [1.56-2.54], respectively; P < 0.01). Sex-based differences in concussion incidence rates for baseball/softball, ice hockey, lacrosse, swimming/diving, and track and field were not statistically significant. In the meta-regression analysis, there were no significant effects on the rate ratio when evaluating study design, setting, and population.

CONCLUSION

Concussion incidence rates were significantly higher in females than in males for soccer and basketball.

A systematic review of sex differences in concussion outcome: What do we know?

Objective: The purpose of this review was to examine sex differences in concussion, or mild traumatic brain injury (mTBI) outcome, updating previous critical reviews of the literature. Method: Within adult human studies, we reviewed a wide range of concussion outcome variables: prevalence of concussion, injury characteristics, postconcussion symptom trajectories and psychiatric distress, neuropsychological performance, and neuroimaging findings. Sports-related concussion, civilian, and military samples were included in the review. Results: Given the robust concussion literature, there is a relative paucity of research addressing sex differences following concussion. The majority of available studies focused on sports-related concussion, with fewer studies targeting other civilian causes of concussion or military-related concussion in females. Prevalence of concussion was generally reported to be higher in females than males. Although symptom reporting largely showed a pattern for females to report greater overall symptoms than males, examining individual symptoms or symptom clusters resulted in mixed findings between the sexes. Neuropsychological studies generally showed females performing more poorly than males on measures of visual memory following concussion, though this finding was not consistently reported. Conclusion: Research examining sex differences in humans following concussion, in general, is in its infancy, and exploration of sex differences in studies outside of the sports concussion domain is particularly nascent. Given the increased prevalence of concussion and potential higher symptom reporting among women, ongoing research is necessary to better understand the role of biological sex on outcome following concussion. Understanding sex differences has important implications for assessment, management, and treatment of concussion.

Difference Between Male and Female Ice Hockey Players in Muscle Activity, Timing, and Head Kinematics During Sudden Head Perturbations

This study examined sex differences in head kinematics and neck muscle activity during sudden head perturbations. Sixteen competitive ice hockey players participated. Three muscles were monitored bilaterally using surface electromyography: sternocleidomastoid, scalene, and splenius capitis. Head and thorax kinematics were measured. Head perturbations were induced by the release of a 1.5-kg weight attached to a wire wrapped around an adjustable pulley secured to the participant's head. Perturbations were delivered in 4 directions (flexion, extension, right lateral bend, and left lateral bend). Muscle onset times, muscle activity, and head kinematics were examined during 3 time periods (2 preperturbation and 1 postperturbation). Females had significantly greater head acceleration during left lateral bend (31.4%, P < .05) and flexion (37.9%, P = .01). Females had faster muscle onset times during flexion (females = 51 ± 11 ms; males = 61 ± 10 ms; P = .001) and slower onset times during left lateral bend and extension. Females had greater left/right sternocleidomastoid and scalene activity during extension (P = .01), with no difference in head acceleration. No consistent neuromuscular strategy could explain all directional sex differences. Females had greater muscle activity postperturbation during extension, suggesting a neuromuscular response to counter sudden acceleration, possibly explaining the lack of head acceleration differences.

Epidemiology of Upper Extremity Soccer Injuries Among High School- and College-Aged Players in the United States: An Analysis of the 1999-2016 NEISS Database

BACKGROUND:

Although lower extremity injuries are more common than upper extremity injuries in high school- and college-aged soccer players, upper extremity injuries may be equally severe. The epidemiology of upper extremity injuries is poorly characterized in this population.

HYPOTHESIS:

Upper extremity injuries are an important contributor to soccer-related morbidity among high school- and college-aged players.

STUDY DESIGN:

Descriptive epidemiology study.

LEVEL OF EVIDENCE:

Level 3.

METHODS:

The National Electronic Injury Surveillance System (NEISS) is a nationally representative sample of 100 hospital emergency departments (EDs). Each record contains demographic and injury information. Records from 1999 to 2016 were analyzed, including patients between the ages of 14 and 23 years with a soccer-related injury sustained at school or during an athletic event.

RESULTS:

A total of 1,299,008 high school- or college-aged patients presented to the ED for a soccer-related injury from 1999 to 2016, of which 20.4% were in the upper extremity. Patients were predominantly male (58.0%) and high school-aged (81.4%). Males constituted a greater proportion of upper extremity injuries when compared with other injury locations (63.5% male for upper extremity). Upper extremity injuries were more likely to be fractures (43.7% vs 13.9%) and dislocations (7.1% vs 3.4%) and less likely to be strains/sprains (27.8% vs 56.6%). Males suffered more shoulder dislocations (81.8% males among patients with shoulder dislocation vs 57.8% among those with other injuries), finger dislocations (72.0% vs 58.0%), upper arm fractures (74.9% vs 57.6%), and forearm fractures (68.3% vs 57.3%).

CONCLUSION:

Upper extremity injuries are frequent in high school- and college-aged soccer players presenting to the ED. Efforts to reduce soccer-related injuries should include strategies targeting the upper extremity, perhaps reducing the incidence of high-energy falls.

CLINICAL RELEVANCE:

Efforts to reduce soccer-related injuries should include strategies targeting upper extremity injuries, particularly among males and college-aged players.