Risk of injury associated with bodychecking experience among youth hockey players

Psychosocial Factors Associated With Time to Recovery After Concussion in Adolescent Ice Hockey Players

OBJECTIVE

To investigate the association between psychosocial factors and physician clearance to return to play (RTP) in youth ice hockey players after sport-related concussion.

DESIGN

Prospective cohort study, Safe to Play (2013-2018).

SETTING

Youth hockey leagues in Alberta and British Columbia, Canada.

PARTICIPANTS

Three hundred fifty-three ice hockey players (aged 11-18 years) who sustained a total of 397 physician-diagnosed concussions.

INDEPENDENT VARIABLES

Psychosocial variables.

MAIN OUTCOME MEASURES

Players and parents completed psychosocial questionnaires preinjury. Players with a suspected concussion were referred for a study physician visit, during which they completed the Sport Concussion Assessment Tool (SCAT3/SCAT5) and single question ratings of distress and expectations of recovery. Time to recovery (TTR) was measured as days between concussion and physician clearance to RTP. Accelerated failure time models estimated the association of psychosocial factors with TTR, summarized with time ratios (TRs). Covariates included age, sex, body checking policy, days from concussion to the initial physician visit, and symptom severity at the initial physician visit.

RESULTS

Self-report of increased peer-related problems on the Strengths and Difficulties Questionnaire (TR, 1.10 [95% CI, 1.02-1.19]), higher ratings of distress about concussion outcomes by participants (TR, 1.06 [95% CI, 1.01-1.11]) and parents (TR, 1.05 [95% CI, 1.01-1.09]), and higher parent ratings of distress about their child's well-being at the time of injury (TR, 1.06 [95% CI, 1.02-1.09]) were associated with longer recovery.

CONCLUSIONS

Greater pre-existing peer-related problems and acute distress about concussion outcomes and youth well-being predicted longer TTR. Treatment targeting these psychosocial factors after concussion may promote recovery.

Factors Associated With Concussion Rates in Youth Ice Hockey Players: Data From the Largest Longitudinal Cohort Study in Canadian Youth Ice Hockey

OBJECTIVES

To examine factors associated with rates of game and practice-related concussion in youth ice hockey.

DESIGN

Five-year prospective cohort (Safe2Play).

SETTING

Community arenas (2013-2018).

PARTICIPANTS

Four thousand eighteen male and 405 female ice hockey players (6584 player-seasons) participating in Under-13 (ages 11-12), Under-15 (ages 13-14), and Under-18 (ages 15-17) age groups.

ASSESSMENT OF RISK FACTORS

Bodychecking policy, age group, year of play, level of play, previous injury in the previous year, lifetime concussion history, sex, player weight, and playing position.

MAIN OUTCOME MEASUREMENTS

All game-related concussions were identified using validated injury surveillance methodology. Players with a suspected concussion were referred to a study sport medicine physician for diagnosis and management. Multilevel Poisson regression analysis including multiple imputation of missing covariates estimated incidence rate ratios (IRRs).

MAIN RESULTS

A total of 554 game and 63 practice-related concussions were sustained over the 5 years. Female players (IRR Female/Male = 1.79; 95% CI: 1.26-2.53), playing in lower levels of play (IRR = 1.40; 95% CI: 1.10-1.77), and those with a previous injury (IRR = 1.46; 95% CI: 1.13, 1.88) or lifetime concussion history (IRR = 1.64; 95% CI: 1.34-2.00) had higher rates of game-related concussion. Policy disallowing bodychecking in games (IRR = 0.54; 95% CI: 0.40-0.72) and being a goaltender (IRR Goaltenders/Forwards = 0.57; 95% CI: 0.38-0.87) were protective against game-related concussion. Female sex was also associated with a higher practice-related concussion rate (IRR Female/Male = 2.63; 95% CI: 1.24-5.59).

CONCLUSIONS

In the largest Canadian youth ice hockey longitudinal cohort to date, female players (despite policy disallowing bodychecking), players participating in lower levels of play, and those with an injury or concussion history had higher rates of concussion. Goalies and players in leagues that disallowed bodychecking had lower rates. Policy prohibiting bodychecking remains an effective concussion prevention strategy in youth ice hockey.

Persisting Concussion Symptoms from Bodychecking: Unrecognized Toll in Boys' Ice Hockey

OBJECTIVES

Youth hockey is a high-impact sport and can cause concussions with lasting effects. We hypothesized that important injury prevention information would accrue from longitudinal tracking of concussed players with persisting concussion symptoms (PCS).

METHODS

This case series comprised 87 consecutive concussed ice hockey players aged 10-18 including 66 males and 21 females referred to our Concussion Clinic from 1997 to 2017 and followed longitudinally by clinic visits and questionnaires.

RESULTS

PCS occurred in 70 (80.4%) of 87 concussed players and lasted 1-168 months in males and 3-26 months in females. Bodychecking was the most common concussion mechanism in 34 (39.1%) players and caused PCS in 24 (70.6%) with symptom duration 4.00 [2.75, 14.50] months (median [IQR]). The remaining 53 players had other concussion mechanisms with PCS in 86.8% (p = 0.113) with similar duration (p = 0.848).

CONCLUSIONS

This is the first longitudinal study of concussion with PCS in youth hockey and showed that symptoms can last for several years. Bodychecking was the commonest mechanism of prolonged disability from concussion in boys and girls' hockey with average PCS duration of 12.3 months but several years in some players. The injury prevention message is to raise the age of permitted bodychecking to 18 in boys' hockey from age 13 to 14 where it is currently. In this case series, this change could have prevented the majority of the bodycheck concussions and several years of suffering from PCS and is strong evidence for raising the permitted age for bodychecking in boys' ice hockey to age 18.

Prevention strategies and modifiable risk factors for sport-related concussions and head impacts: a systematic review and meta-analysis

OBJECTIVES

To evaluate prevention strategies, their unintended consequences and modifiable risk factors for sport-related concussion (SRC) and/or head impact risk.

DESIGN

This systematic review and meta-analysis was registered on PROSPERO (CRD42019152982) and conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA SOURCES

Eight databases (MEDLINE, CINAHL, APA PsycINFO, Cochrane (Systematic Review and Controlled Trails Registry), SPORTDiscus, EMBASE, ERIC0 were searched in October 2019 and updated in March 2022, and references searched from any identified systematic review.

ELIGIBILITY CRITERIA

Study inclusion criteria were as follows: (1) original data human research studies, (2) investigated SRC or head impacts, (3) evaluated an SRC prevention intervention, unintended consequence or modifiable risk factor, (4) participants competing in any sport, (5) analytic study design, (6) systematic reviews and meta-analyses were included to identify original data manuscripts in reference search and (7) peer-reviewed. Exclusion criteria were as follows: (1) review articles, pre-experimental, ecological, case series or case studies and (2) not written in English.

RESULTS

In total, 220 studies were eligible for inclusion and 192 studies were included in the results based on methodological criteria as assessed through the Scottish Intercollegiate Guidelines Network high ('++') or acceptable ('+') quality. Evidence was available examining protective gear (eg, helmets, headgear, mouthguards) (n=39), policy and rule changes (n=38), training strategies (n=34), SRC management strategies (n=12), unintended consequences (n=5) and modifiable risk factors (n=64). Meta-analyses demonstrated a protective effect of mouthguards in collision sports (incidence rate ratio, IRR 0.74; 95% CI 0.64 to 0.89). Policy disallowing bodychecking in child and adolescent ice hockey was associated with a 58% lower concussion rate compared with bodychecking leagues (IRR 0.42; 95% CI 0.33 to 0.53), and evidence supports no unintended injury consequences of policy disallowing bodychecking. In American football, strategies limiting contact in practices were associated with a 64% lower practice-related concussion rate (IRR 0.36; 95% CI 0.16 to 0.80). Some evidence also supports up to 60% lower concussion rates with implementation of a neuromuscular training warm-up programme in rugby. More research examining potentially modifiable risk factors (eg, neck strength, optimal tackle technique) are needed to inform concussion prevention strategies.

CONCLUSIONS

Policy and rule modifications, personal protective equipment, and neuromuscular training strategies may help to prevent SRC.

PROSPERO REGISTRATION NUMBER

CRD42019152982.

Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport-Amsterdam, October 2022

For over two decades, the Concussion in Sport Group has held meetings and developed five international statements on concussion in sport. This 6th statement summarises the processes and outcomes of the 6th International Conference on Concussion in Sport held in Amsterdam on 27-30 October 2022 and should be read in conjunction with the (1) methodology paper that outlines the consensus process in detail and (2) 10 systematic reviews that informed the conference outcomes. Over 3½ years, author groups conducted systematic reviews of predetermined priority topics relevant to concussion in sport. The format of the conference, expert panel meetings and workshops to revise or develop new clinical assessment tools, as described in the methodology paper, evolved from previous consensus meetings with several new components. Apart from this consensus statement, the conference process yielded revised tools including the Concussion Recognition Tool-6 (CRT6) and Sport Concussion Assessment Tool-6 (SCAT6, Child SCAT6), as well as a new tool, the Sport Concussion Office Assessment Tool-6 (SCOAT6, Child SCOAT6). This consensus process also integrated new features including a focus on the para athlete, the athlete's perspective, concussion-specific medical ethics and matters related to both athlete retirement and the potential long-term effects of SRC, including neurodegenerative disease. This statement summarises evidence-informed principles of concussion prevention, assessment and management, and emphasises those areas requiring more research.

Are Self-Reported and Parent-Reported Attention Problems and Hyperactivity Associated With Higher Rates of Concussion in Youth Ice Hockey Players?

OBJECTIVE

To examine the association between self-reported and parent-reported attention problems and hyperactivity and rates of injury and concussion in Canadian youth ice hockey players.

DESIGN

Secondary analyses of 2 prospective cohort studies.

SETTING

Canadian youth ice hockey teams.

PARTICIPANTS

Ice hockey players (ages 11-17 years) were recruited by team, over 4 seasons (2011-2016). A combined 1709 players contributing 1996 player-seasons were analyzed (257 players participated in more than one season).

ASSESSMENT OF RISK FACTORS

Data were collected from preseason baseline questionnaires, including child and parent proxy forms of the Behavior Assessment System for Children, second edition.

MAIN OUTCOME MEASURES

Injury and concussion rates and incidence rate ratios (IRR) comparing players with and without self-identified or parent-identified attention problems and hyperactivity, adjusted for covariates (ie, body checking policy, previous injury/concussion, and age) and a random effect for team, were estimated using multiple multilevel negative binomial regression.

RESULTS

When analyzed continuously, rates of concussion increased with higher self-reported and parent-reported measures of attention problems [IRR SELF = 1.025; 95% confidence interval (CI): 1.011-1.040; IRR PARENT = 1.032; 95% CI: 1.008-1.057]. Self-reported hyperactivity was significantly associated with concussion (IRR = 1.021; 95% CI: 1.007-1.035), but parent-reported hyperactivity was not (IRR = 1.005; 95% CI: 0.983-1.028). A T score ≥ 60 cutoff combining attention problems and hyperactivity scores (an estimate of probable attention-deficit hyperactivity disorder) was not significantly associated with rates of injury or concussion.

CONCLUSIONS

Attention problems and hyperactivity may place youth ice hockey players at increased risk of concussion and injury. Preseason assessments could identify players for targeted concussion education and risk reduction strategies.

No association found between body checking experience and injury or concussion rates in adolescent ice hockey players

OBJECTIVES

To compare rates of injury and concussion among U-15 (ages 13-14 years) ice hockey players playing in leagues allowing body checking, but who have a varying number of years of body checking experience.

METHODS

This 5-year longitudinal cohort included U-15 ice hockey players playing in leagues where policy allowed body checking. Years of body checking experience were classified based on national/local body checking policy. All ice hockey game-related injuries were identified using a validated injury surveillance methodology. Players with a suspected concussion were referred to a study sport medicine physician. Multiple multilevel Poisson regression analysis was performed, adjusting for important covariates and a random effect at a team level (offset by game exposure hours), to estimate injury and concussion incidence rate ratios (IRRs).

RESULTS

In total, 1647 players participated, contributing 1842 player-seasons (195 players participating in two seasons). Relative to no body checking experience, no significant differences were found in the adjusted IRRs for game-related injury for players with 1 year (IRR=1.06; 95% CI: 0.77 to 1.45) or 2+ years (IRR=1.16; 95% CI: 0.74 to 1.84) body checking experience. Similarly, no differences were found in the rates of concussion for players with 1 year (IRR=0.92; 95% CI: 0.59 to 1.42) or 2+ years (IRR=0.69; 95% CI: 0.38 to 1.25) body checking experience.

CONCLUSIONS

Among ice hockey players aged 13-14 years participating in leagues permitting body checking, the adjusted rates of all injury and concussion were not significantly different between those that had body checking experience and those that did not. Based on these findings, no association was found between body checking experience and rates of injury or concussion specifically in adolescent ice hockey.

Injuries in Canadian high school boys’ collision sports: insights across football, ice hockey, lacrosse, and rugby

Background

Collision sport participation rates among high school youth in Canada are high. While participation is beneficial for physical and mental well-being, the rates of injury in these sports are high.

Aims

This study aims to compare injury rates and profiles across four common youth collision sports (ice hockey, tackle football, lacrosse, rugby).

Methods

Data from a cross-sectional questionnaire of 2029 high school youth were used to identify male collision sport participants to be included in this secondary analysis (n = 360).

Results

Of the 2029 students who completed the questionnaire, 360 participated in collision-based sports [Ages: 14 (5%), 15 (41%), 16 (25%), 17 (26%), 18 (3%)]. The rates of injury ranged from 12.7 injuries/100 participants/year (rugby) to 33.1 injuries/100 participants/year (ice hockey). Concussion rates ranged from 12.4 (football) to 15.8 (ice hockey) concussions/100 participants/year. Similarities existed in the profile of injuries between sports, with most injuries occurring due to contact with another player (range 57.0% to 87.5%). Injuries to the head (33.3%), wrist/hand (16.0%), shoulder (12.8%), and knee (12.0%) were the most prevalent injury type. Substantial differences in previous playing experience existed between sports.

Discussion

The high rate of injury and concussion reported across each of these sports highlights the need for the introduction of primary prevention strategies in these sports aimed to reduce the risk of injury.

Bodychecking experience and rates of injury among ice hockey players aged 15-17 years

BACKGROUND

Although high rates of injury occur in youth ice hockey, disagreements exist about the risks and benefits of permitting bodychecking. We sought to evaluate associations between experience with bodychecking and rates of injury and concussion among ice hockey players aged 15-17 years.

METHODS

We obtained data from a prospective cohort study of ice hockey players aged 15-17 years in Alberta who played in leagues that permitted bodychecking. We collected data over 3 seasons of play (2015/16-2017/18). We compared players based on experience with bodychecking (≤ 2 v. ≥ 3 yr), estimated using local and national bodychecking policy and region of play. We used validated methodology of ice hockey injury surveillance to identify all injuries related to ice hockey games and defined concussions according to the Consensus Statement on Concussion in Sport.

RESULTS

We included 941 players who contributed to 1168 player-seasons, with 205 players participating in more than 1 season. Compared with players with 2 years or less of bodychecking experience, those with 3 or more years of experience had higher rates of all injury (adjusted incidence rate ratio [IRR] 2.55, 95% confidence interval [CI] 1.57-4.14), injury with more than 7 days of time loss (adjusted IRR 2.65, 95% CI 1.50-4.68) and concussion (adjusted IRR 2.69, 95% CI 1.34-5.42).

INTERPRETATION

Among ice hockey players aged 15-17 years who participated in leagues permitting bodychecking, more experience with bodychecking did not protect against injury. This provides further support for removing bodychecking from youth ice hockey.

National Athletic Trainers' Association Position Statement: Reducing Intentional Head-First Contact Behavior in American Football Players

OBJECTIVE

To provide evidence-based recommendations for reducing the prevalence of head-first contact behavior in American football players with the aim of reducing the risk of head and neck injuries.

BACKGROUND

In American football, using the head as the point of contact is a persistent, well-documented, and direct cause of catastrophic head and cervical spine injury. Equally concerning is that repeated head-impact exposures are likely to result from head-first contact behavior and may be associated with long-term neurocognitive conditions such as dementia, depression, and chronic traumatic encephalopathy.

CONCLUSIONS

The National Athletic Trainers' Association proposes 14 recommendations to help the certified athletic trainer, allied health care provider, coach, player, parent, and broader community implement strategies for reducing the prevalence of head-first contact in American football.

Body checking in non-elite adolescent ice hockey leagues: it is never too late for policy change aiming to protect the health of adolescents

OBJECTIVES

The objective of this study is to evaluate the effect of policy change disallowing body checking in adolescent ice hockey leagues (ages 15-17) on reducing rates of injury and concussion.

METHODS

This is a prospective cohort study. Players 15-17 years-old were recruited from teams in non-elite divisions of play (lower 40%-70% by division of play depending on year and city of play in leagues where policy permits or prohibit body checking in Alberta and British Columbia, Canada (2015-18). A validated injury surveillance methodology supported baseline, exposure-hours and injury data collection. Any player with a suspected concussion was referred to a study physician. Primary outcomes include game-related injuries, game-related injuries (>7 days time loss), game-related concussions and game-related concussions (>10 days time loss).

RESULTS

44 teams (453 player-seasons) from non-body checking and 52 teams (674 player-seasons) from body checking leagues participated. In body checking leagues there were 213 injuries (69 concussions) and in non-body checking leagues 40 injuries (18 concussions) during games. Based on multiple multilevel mixed-effects Poisson regression analyses, policy prohibiting body checking was associated with a lower rate of injury (incidence rate ratio (IRR): 0.38 (95% CI 0.24 to 0.6)) and concussion (IRR: 0.49; 95% CI 0.26 to 0.89). This translates to an absolute rate reduction of 7.82 injuries/1000 game-hours (95% CI 2.74 to 12.9) and the prevention of 7326 injuries (95% CI 2570 to 12083) in Canada annually.

CONCLUSIONS

The rate of injury was 62% lower (concussion 51% lower) in leagues not permitting body checking in non-elite 15-17 years old leagues highlighting the potential public health impact of policy prohibiting body checking in older adolescent ice hockey players.

Facemasks Block Lower Visual Field in Youth Ice Hockey

Wearing a facemask (FM) reduces the spread of COVID-19, but it also blocks a person's lower visual field. Many new public safety rules were created in response to COVID-19, including mandated FM wearing in some youth sports like youth ice hockey. We hypothesized that FM wearing in youth hockey players obstructs the lower field of view and may impact safety. Youth hockey players (n = 33) aged 12.03 (1.6) years button press when they saw an LED on the floor turn on in two conditions (wearing FM or no FM) in random order. An interleaved one-up/one-down two-alternative-forced-choice adaptive staircase design was used. Visual thresholds were calculated for each condition and participant. The visual angle threshold (VAT) was determined using standing eye height and the linear distance from the tip of the skates to the visual threshold. Paired t-tests determined whether mask wearing changed the VAT. We modeled the probability a player could see the puck on their stick in four distinct scenarios to estimate the potential impact of FM wearing during hockey play. The average unmasked VAT (11.4 degrees) was significantly closer to the skates than the masked VAT (20.3 degrees) (p < 0.001). Our model indicated a significant reduction in ability to visualize the puck using peripheral vision when more upright while wearing a FM. FM wearing compromised their lower visual field, suggesting a downward head tilt may be necessary to see the puck. Playing ice hockey while wearing a FM may lead to unsafe on-ice playing conditions due to downward head tilt to see the puck.

Concussion Among Children in the United States General Population: Incidence and Risk Factors

The objective of this study was to examine the incidence of concussion and risk factors for sustaining concussion among children from the United States general population. This prospective cohort study used data from the Adolescent Brain Cognitive Development (ABCD) Study^®. Children were recruited from schools across the US, sampled to reflect the sociodemographic variation of the US population. The current sample includes 11,013 children aged 9 to 10 years old (47.6% girls; 65.5% White) who were prospectively followed for an average of 1 year (mean = 367.9 days, SD = 40.8, range 249–601). The primary outcome was caregiver-reported concussion during a 1 year follow-up period. Logistic regression was used to determine which potential clinical, health history, and behavioral characteristics (assessed at baseline) were prospectively associated with concussion. In the 1 year follow-up period between ages 10 and 11, 1 in 100 children (n = 123, 1.1%) sustained a concussion. In univariate models, three baseline predictors (ADHD, prior concussion, and accident proneness) were significantly associated with sustaining a concussion. In a multivariate model, controlling for all other predictors, only prior concussion remained significantly associated with the occurrence of a concussion during the observation period (Odds Ratio = 5.49, 95% CI: 3.40–8.87). The most robust and only independent prospective predictor of sustaining a concussion was history of a prior concussion. History of concussion is associated with 5.5 times greater odds of sustaining concussion between ages 10 and 11 among children from the general US population.

Blood-Brain Barrier Breakdown and Astrocyte Reactivity Evident in the Absence of Behavioral Changes after Repeated Traumatic Brain Injury

Repeated traumatic brain injuries (TBIs) cause debilitating effects. Without understanding the acute effects of repeated TBIs, treatment options to halt further degeneration and damage cannot be developed. This study sought to examine the acute effects of blood-brain barrier (BBB) dysfunction, edema, inflammation and behavioral changes after either a single or double TBI using a C57BL/6 mouse model. We examined the effects of one or two TBIs, of either a mild or moderate severity. Double injuries were spaced 7 days apart, and all analysis was performed 24 h post-injury. To examine edema and inflammation, protein levels of glial fibrillary acidic protein (GFAP), S100 calcium-binding protein B, interleukin-6, and matrix metallopeptidase 9 (MMP9) were analyzed. Aquaporin-4 (AQP4) and zonula occludens-1 (ZO-1) were analyzed to observe BBB dysfunction. Ionized calcium-binding adapter molecule 1 (IBA1) was analyzed to observe microglial activation. Rotarod, beam walking, and grip strength tests were used to measure changes in physical behavior post-injury. A sample size of ≥5 was used for all analysis. Double injuries led to an increase in BBB breakdown, as indicated by altered MMP-9, AQP4, and ZO-1 protein expression. Single injuries showed an increase in microglial activation, astrocyte activation, and BBB breakdown. Behavioral tasks showed no significant differences between injured and control groups. Based on our findings, we suggest that behavioral studies should not be used as the sole clinical indicator on brain tissue recovery. Analysis of markers such as IBA1, GFAP, MMP-9, AQP4, and ZO-1 provide valuable insight on pathophysiological response to injury.

Differences in Head Impact Exposures Between Youth Tackle and Flag Football Games and Practices: Potential Implications for Prevention Strategies

BACKGROUND

Interventions designed to reduce the risk for head impacts and concussion in youth football have increased over the past decade; however, understanding of the role of regular game play on head impact exposure among youth tackle and flag football athletes is currently limited.

PURPOSE

To explore head impact exposure among youth tackle and flag football athletes (age range, 6-14 years) during both practices and games.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Using the Vector MouthGuard sensor, the authors collected head impact data from 524 tackle and flag youth football athletes over the course of a football season. Quantities of interest were estimated from regression models using Bayesian methods.

RESULTS

For impacts ≥10g, a tackle football athlete had an estimated 17.55 (95% CI, 10.78-28.96) times more head impacts per practice compared with a flag football athlete (6.85 [95% CI, 6.05-7.76] and 0.39 [95% CI, 0.24-0.62] head impacts, respectively). Additionally, a tackle football athlete had an estimated 19.48 (95% CI, 12.74-29.98) times more head impacts per game compared with a flag football athlete (13.59 [95% CI, 11.97-15.41] and 0.70 [95% CI, 0.46-1.05] head impacts, respectively). Among tackle football athletes, the estimated average impact rate was 6.51 (95% CI, 5.75-7.37) head impacts during a practice and 12.97 (95% CI, 11.36-14.73) impacts during a game, resulting in 2.00 (95% CI, 1.74-2.29) times more ≥10g head impacts in games versus practices. Tackle football athletes had 2.06 (95% CI, 1.80-2.34) times more high-magnitude head impacts (≥40g) during a game than during a practice. On average, flag football athletes experienced an estimated 0.37 (95% CI, 0.20-0.60) head impacts during a practice and 0.77 (95% CI, 0.53-1.06) impacts during a game, resulting in 2.06 (95% CI, 1.29-3.58) times more ≥10g head impacts in games versus practices. Because of model instability caused by a large number of zero impacts for flag football athletes, a comparison of high-magnitude head impacts is not reported for practices or games.

CONCLUSION

This study provides a characterization of the head impact exposure of practices and games among a large population of youth tackle and flag football athletes aged 6 to 14 years. These findings suggest that a greater focus on game-based interventions, such as fair play interventions and strict officiating, may be beneficial to reduce head impact exposures for youth football athletes.

Proceedings From the Ice Hockey Summit III: Action on Concussion

OBJECTIVES

The Ice Hockey Summit III provided updated scientific evidence on concussions in hockey to inform these 5 objectives: (1) describe sport related concussion (SRC) epidemiology; (2) classify prevention strategies; (3) define objective, diagnostic tests; (4) identify treatment; and (5) integrate science and clinical care into prioritized action plans and policy.

METHODS

Our action plan evolved from 40 scientific presentations. The 155 attendees (physicians, athletic trainers, physical therapists, nurses, neuropsychologists, scientists, engineers, coaches, and officials) voted to prioritize these action items in the final Summit session.

RESULTS

To (1) establish a national and international hockey database for SRCs at all levels; (2) eliminate body checking in Bantam youth hockey games; (3) expand a behavior modification program (Fair Play) to all youth hockey levels; (4) enforce game ejection penalties for fighting in Junior A and professional hockey leagues; (5) establish objective tests to diagnose concussion at point of care; and (6) mandate baseline testing to improve concussion diagnosis for all age groups.

CONCLUSIONS

Expedient implementation of the Summit III prioritized action items is necessary to reduce the risk, severity, and consequences of concussion in the sport of ice hockey.

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.

A Qualitative Study of Youth Football Coaches' Perception of Concussion Safety in American Youth Football and Their Experiences With Implementing Tackling Interventions

Due in part to concern about the potential long-term effects of concussion and repetitive head injuries in football, some programs have implemented tackling interventions. This paper explores youth football coaches' perception of football safety and their experiences implementing these interventions aimed at athlete safety. Using a qualitative approach, coaches were interviewed by means of a semi-structured protocol that covered: (a) demographics; (b) background and experiences; (c) personal relevance risks, safety, and benefits of youth football; (d) experiences with tackling technique; (e) experiences with mouth guard sensors; and (f) opinions on disseminating information on football safety. Most coaches felt that learning tackling at a young age helped prepare them for their playing later in life and believed that youth should begin playing tackle football at a young age. Coaches were mixed regarding their concerns about the risk for concussion and subconcussive head impacts. Still, most were receptive to changes in rules and policies aimed at making football safer. Findings from this study demonstrate that youth football coaches are important stakeholders to consider when implementing changes to youth football. Understanding coach perceptions and experiences may inform future efforts aimed to educate coaches on rules and policies to make the game safer for youth athletes.

Concussion Burden, Recovery, and Risk Factors in Elite Youth Ice Hockey Players

OBJECTIVE

To examine rates of concussion and more severe concussion (time loss of greater than 10 days) in elite 13- to 17-year-old ice hockey players.

METHODS

This is a prospective cohort study (Alberta, Canada). Bantam (13-14 years) and Midget (15-17 years) male and female elite (top 20% by division of play) youth ice hockey players participated in this study. Players completed a demographic and medical history questionnaire and clinical test battery at the beginning of the season. A previously validated injury surveillance system was used to document exposure hours and injury during one season of play (8 months). Players with a suspected ice hockey-related concussion were referred to the study sport medicine physicians for assessment. Time loss from hockey participation was documented on an injury report form.

RESULTS

Overall, 778 elite youth ice hockey players (659 males and 119 females; aged 13-17 years) participated in this study. In total, 143 concussions were reported. The concussion incidence rate (IR) was 17.60 concussions/100 players (95% CI, 15.09-20.44). The concussion IR was 1.31 concussions/1000 player-hours (95% CI, 1.09-1.57). Time loss of greater than 10 days was reported in 74% of cases (106/143), and 20% (n = 28) had time loss of greater than 30 days.

CONCLUSIONS

Concussion is a common injury in elite youth ice hockey players. In this study population, a large proportion of concussions (74%) resulted in a time loss of greater than 10 days, possibly reflecting more conservative management or longer recovery in youth athletes.

Recovery of Theta Frequency Oscillations in Rats Following Lateral Fluid Percussion Corresponds With a Mild Cognitive Phenotype

Whether from a fall, sports concussion, or even combat injury, there is a critical need to identify when an individual is able to return to play or work following traumatic brain injury (TBI). Electroencephalogram (EEG) and local field potentials (LFP) represent potential tools to monitor circuit-level abnormalities related to learning and memory: specifically, theta oscillations can be readily observed and play a critical role in cognition. Following moderate traumatic brain injury in the rat, lasting changes in theta oscillations coincide with deficits in spatial learning. We hypothesized, therefore, that theta oscillations can be used as an objective biomarker of recovery, with a return of oscillatory activity corresponding with improved spatial learning. In the current study, LFP were recorded from dorsal hippocampus and anterior cingulate in awake, behaving adult Sprague Dawley rats in both a novel environment on post-injury days 3 and 7, and Barnes maze spatial navigation on post-injury days 8–11. Theta oscillations, as measured by power, theta-delta ratio, peak theta frequency, and phase coherence, were significantly altered on day 3, but had largely recovered by day 7 post-injury. Injured rats had a mild behavioral phenotype and were not different from shams on the Barnes maze, as measured by escape latency. Injured rats did use suboptimal search strategies. Combined with our previous findings that demonstrated a correlation between persistent alterations in theta oscillations and spatial learning deficits, these new data suggest that neural oscillations, and particularly theta oscillations, have potential as a biomarker to monitor recovery of brain function following TBI. Specifically, we now demonstrate that oscillations are depressed following injury, but as oscillations recover, so does behavior.

What is the risk of recurrent concussion in children and adolescents aged 5-18 years? A systematic review and meta-analysis

OBJECTIVE

We aimed to examine the risk of concussion in children with a previous history of concussion.

DESIGN

Systematic review and meta-analysis. The primary outcome was number of children with and without a previous lifetime history of concussion who sustained a diagnosed concussion within each study period. Risk of bias was assessed using the Newcastle-Ottawa Scale. A random effects model was used to estimate a pooled risk ratio (RR) with corresponding 95% CIs; results were summarised in forest plots.

DATA SOURCES

Four electronic databases (MEDLINE, Embase, CINAHL, SPORTDiscus) and selected reference lists were searched (PROSPERO registration No CRD42019135462).

ELIGIBILITY CRITERIA

Original English language peer-reviewed publications that compared concussion risk in children aged 5-18 years with and without a previous concussion history in which risk estimates were reported or able to be calculated.

RESULTS

Of 732 identified studies, 7 studies representing 23 411 children (risk of bias range, 7-9; maximum possible score=9) were included for meta-analysis. Pooled risk of sustaining a concussion was more than three times greater in children with a previous concussion compared with those with no previous concussion (RR=3.64; 95% CI: 2.68 to 4.96; p<0.0001; I ²=90.55%). Unreported sex-stratified data precluded direct comparison of concussion risk in male versus female athletes.

CONCLUSION

Previously concussed children have four times the risk of sustaining a concussion compared with those with no previous concussion history. This should be a consideration for clinicians in return to sport decision-making. Future studies examining subsequent recurrent concussion in youth sports must consider sex differences.

A new model of repeat mTBI in adolescent rats

Sports-related injury is frequently associated with repeated diffuse and mild traumatic brain injury (mTBI). We combined two existing models for inducing TBI in rats, the Impact Acceleration and Controlled Cortical Impact models, to create a new method relevant to the study of cognitive sequelae of repeat mTBI in adolescent athletes. Repeated mTBI, such as those incurred in sports, can result in a wide range of outcomes, with many individuals experiencing no chronic sequela while others develop profound cognitive and behavioral impairments, typically in the absence of lasting motor symptoms or gross tissue loss appreciable antemortem. It is critical to develop models of mTBI and repeat mTBI that have the flexibility to assess multiple parameters related to injury (e.g. number and magnitude of impacts, inter-injury interval, etc) that are associated with brain vulnerability compared to normal recovery. We designed a 3D-printed plastic implant to permanently secure a metal disc to the skull of adolescent rats in order to induce multiple injuries without performing multiple survival surgeries and also to minimize pre-injury anesthesia time. Rats were randomly assigned to sham injury (n = 12), single injury (n = 12; injury on P41), or repeat injury (n = 14; injuries on P35, P38, and P41) groups. Compared to single injury and sham injury, repeat injuries caused increased toe pinch reflex latency (F(2,34) = 4.126, p < .05) and diminished weight gain (F(2, 34) = 4.767, p < .05). Spatial navigation was tested using Morris water maze, beginning one week after the final injury (P48). While there were no differences between groups during acquisition, both single and repeat injuries resulted in deficits on probe trial performance (p < .01 and p < .05 respectively). Single injury animals also exhibited a deficit in working memory deficit across three days of testing (p < .05). Neither injury group had neuronal loss in the hilus or CA3, according to stereological quantification of NeuN. Therefore, by implanting a helmet we have created a relevant model of sports-related injury and repeated mTBI that results in subtle but significant changes in cognitive outcome in the absence of significant hippocampal cell death.

Does disallowing body checking in non-elite 13- to 14-year-old ice hockey leagues reduce rates of injury and concussion? A cohort study in two Canadian provinces

OBJECTIVE

To compare rates of injury and concussion among non-elite (lowest 60% by division of play) Bantam (ages 13-14 years) ice hockey leagues that disallow body checking to non-elite Bantam leagues that allow body checking.

METHODS

In this 2-year cohort study, Bantam non-elite ice hockey players were recruited from leagues where policy allowed body checking in games (Calgary/Edmonton 2014-2015, Edmonton 2015-2016) and where policy disallowed body checking (Kelowna/Vancouver 2014-2015, Calgary 2015-2016). All ice hockey game-related injuries resulting in medical attention, inability to complete a session and/or time loss from hockey were identified using valid injury surveillance methodology. Any player suspected of having concussion was referred to a study physician for diagnosis and management.

RESULTS

49 body checking (608 players) and 33 non-body checking teams (396 players) participated. There were 129 injuries (incidence rate (IR)=7.98/1000 hours) and 54 concussions (IR=3.34/1000 hours) in the body checking teams in games. After policy change, there were 31 injuries (IR=3.66/1000 hours) and 17 concussions (IR=2.01/1000 hours) in games. Policy disallowing body checking was associated with a lower rate of all injury (adjusted incidence rate ratio (IRR)=0.44; 95% CI: 0.27 to 0.74). The point estimate showed a lower rate of concussion (adjusted IRR=0.6; 95% CI: 0.31 to 1.18), but this was not statistically significant.

CONCLUSION

Policy change disallowing body checking in non-elite Bantam ice hockey resulted in a 56% lower rate of injury. There is growing evidence that disallowing body checking in youth ice hockey is associated with fewer injuries.

Factors Associated With Self-Reported Concussion History in Middle School Athletes

OBJECTIVE

Identifying personal characteristics associated with sustaining a concussion is of great interest, yet only a few have examined this in children. The purpose of this study was to examine the association between sex, neurodevelopmental disorders, health history, and lifetime history of self-reported concussion in 12- and 13-year-old athletes.

DESIGN

Cross-sectional study.

SETTING

Middle schools.

PARTICIPANTS

Participants were 1744 twelve- and thirteen-year-old student athletes who completed preseason Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) testing, including a self-report questionnaire about previous concussions, developmental diagnoses, and previous medical treatment.

INDEPENDENT VARIABLES

Age, sex, attention-deficit/hyperactivity disorder (ADHD), learning disabilities (LDs), and previous treatment for migraine.

MAIN OUTCOME MEASURES

Self-reported history of concussion.

RESULTS

A minority of athletes (13.7%) reported previous concussions (1 concussion, n = 181; 2 concussions, n = 41; and 3+ concussions, n = 17). A small proportion reported a history of ADHD (4.4%), LD (2.8%) or migraine treatment (4.0%). Higher rates of self-reported previous concussions were associated with male sex [16.9% vs 9.1%; χ(1) = 21.47, P < 0.001] and previous migraine treatment [31.9% vs 13.0%; χ(1) = 20.08, P < 0.001]. There were no differences in self-reported concussion history between 12- and 13-year olds (P = 0.18) and those with/without ADHD (P = 0.41) or LDs (P = 0.06). The overall logistic regression model was statistically significant [χ(5) = 42.01, P < 0.001] but explained only 4.3% of the variance. Previous treatment for migraine [P < 0.001, Exp(B) = 3.30] and male sex [P < 0.001, Exp(B) = 2.06] were independently associated with a self-reported concussion history, whereas age, LD, and ADHD were not (P's > 0.05).

CONCLUSIONS

Male sex and previous migraine treatment were associated with higher rates of self-reported previous concussions in both independent and multivariate models in middle school athletes, whereas age, ADHD, and LDs were not.

Mouthguard use in youth ice hockey and the risk of concussion: nested case–control study of 315 cases

Background

Concussion is the most common injury in youth ice hockey. Whether mouthguard use lowers the odds of concussion remains an unanswered question.

Objective

To determine the association between concussion and mouthguard use in youth ice hockey.

Methods

Nested case–control design. Cases and controls were identified from two prospective cohort studies using valid injury surveillance methods. Cases were players concussed during a game or practice; controls were players who sustained a non-concussion injury during a game or practice. The primary exposure was mouthguard use at time of injury; mouthguard type (dental custom fit or off the shelf) was a secondary exposure. Physician-diagnosed or therapist-suspected concussion was the primary outcome. Dental injury was a secondary outcome. Multilevel logistic regression with random effect at a team level was used to obtain ORs for the mouthguard effect, adjusted for level of play, age group, position, concussion history, mechanism of injury, cohort, session type and body checking policy.

Results

Among cases, 236/315 (75%) were wearing a mouthguard at time of injury, while 224/270 (83%) controls were wearing a mouthguard at time of injury. Any mouthguard use was associated with an adjusted OR for concussion of 0.36 (95% CI 0.17 to 0.73). Off-the-shelf mouthguards were associated with a 69% lower odds of concussion (adjusted OR: 0.31; 95% CI 0.14 to 0.65). Dental custom-fit mouthguards were associated with a non-significant 49% lower odds of concussion (adjusted OR: 0.51; 95% CI 0.22 to 1.10). No dental injuries were identified in either cohort.

Conclusion

Mouthguard use was associated with lower odds of concussion. Players should be required to wear mouthguards in youth ice hockey.

Frontal theta-gamma ratio is a sensitive index of concussion history in athletes on tasks of visuo-motor control

Patients with mTBI often show deficits in executive function and changes in neural activity. Similar changes in those with a history of mTBI (i.e. concussion), however, have not been consistently reported. Frontal theta-to-gamma frequency ratio has shown promise in EEG research in predicting performance on working memory tasks. In the present study we explored the sensitivity of the frontal theta-to-gamma relative power spectral density (PSD) ratio to the history of concussion in 81 youth athletes (18 with a history of concussion, ages 13–18) during the tests of the Nike Sensory Training Station that vary in working memory and processing speed demands and motor output requirements. The results showed that the theta-to-gamma relative PSD ratio was significantly lower in the concussion history group on the tests of target capture, perception span and hand reaction time. A principle component analysis further indicated that this metric reflects an underlying dimension shared by several visuo-motor control tests of the Nike battery. The results suggested persistent deficits in psychomotor ability in the athletes with a history of concussion that may have implications for diagnosis, rehabilitation and athletic training.

What Is Injury in Ice Hockey: An Integrative Literature Review on Injury Rates, Injury Definition, and Athlete Exposure in Men's Elite Ice Hockey

Injuries in men's elite ice hockey have been studied over the past 40 years, however, there is a lack of consensus on definitions of both injury and athlete exposure. These inconsistencies compromise the reliability and comparability of the research. While many individual studies report injury rates in ice hockey, we are not aware of any literature reviews that have evaluated the definitions of injury and athlete exposure in men's elite ice hockey. The purpose of this integrative review was to investigate the literature on hockey musculoskeletal injury to determine injury rates and synthesize information about the definitions of injury and athlete exposure. Injury rates varied from 13.8/1000 game athlete exposures to 121/1000 athlete exposures as measured by player-game hours. The majority of variability between studies is explained by differences in the definitions of both injury and athlete exposure. We were unable to find a consensus injury definition in elite ice hockey. In addition, we were unable to observe a consistent athlete exposure metric. We recommend that a consistent injury definition be adopted to evaluate injury risk in elite ice hockey. We recommend that injuries should be defined by a strict list that includes facial lacerations, dental injuries, and fractures. We also recommend that athlete exposure should be quantified using player-game hours.

Prevention of Concussion

Concussion is a common pediatric problem, and the best point of intervention would be to prevent a concussion from occurring. Unfortunately, information in this area has inconsistent support for the various methods that have been attempted. In infants, concussions are typically related to safety hazards in the environment and attempts to make the environment safer have resulted in decreased injuries over time. Toddlers also face environmental hazards that are slightly different in light of their increased mobility. School-aged children and adolescents primarily sustain concussions in the course of participation in organized contact sports. Although much research has been devoted to protective equipment, there is not a clearly effective piece of equipment that prevents concussions. Some effect has been demonstrated with changes in rules and policy that limit or eliminate certain kinds of dangerous contact. Research is still being performed to adequately evaluate methods that are already being used, as well as to find new methods in the future that may help protect today's children from concussions.

The Stability of Retrospective Pre-injury Symptom Ratings Following Pediatric Concussion

Objective: To determine the stability of children's retrospective ratings of pre-injury levels of symptoms over time following concussion.

Methods: Children and adolescents (n = 3,063) between the ages of 5–17 diagnosed with a concussion by their treating pediatric emergency department (PED) physician within 48 h of injury completed the Post-Concussion Symptom Inventory (PCSI) at the PED and at 1, 2, 4, 8, and 12-weeks post-injury. At each time point, participants retrospectively recalled their pre-injury levels of post-injury symptoms. The PCSI has three age-appropriate versions for children aged 5–7 (PCSI-SR5), 8–12 (PCSI-SR8), and 13–18 (PCSI-SR13). Total scale, subscales (physical, cognitive, emotional, and sleep), and individual items from the PCSI were analyzed for stability using Gini's mean difference (GMD).

Results: The mean GMD for total score was 0.31 (95% CI = 0.28, 0.34) for the PCSI-SR5, 0.19 (95% CI = 0.18, 0.20) for the PCSI-SR8, and 0.17 (95% CI = 0.16, 0.18) for the PCSI-SR13. Subscales ranged from mean GMD 0.18 (physical) to 0.31 (emotional) for the PCSI-SR8 and 0.16 (physical) to 0.31 (fatigue) for the PCSI-SR13. At the item-level, mean GMD ranged from 0.13 to 0.60 on the PCSI-SR5, 0.08 to 0.59 on the PCSI-SR8, and 0.11 to 0.41 on the PCSI-SR13.

Conclusions: Children and adolescents recall their retrospective pre-injury symptom ratings with good-to-perfect stability over the first 3-months following their concussion. Although some individual items underperformed, variability was reduced as items were combined at the subscale and full-scale level. There is limited benefit gained from collecting multiple pre-injury symptom queries.

Clinical Trial Registration: Clinicaltrials.gov through the US National Institute of Health/National Library of Medicine. (NCT01873287; http://clinicaltrials.gov/ct2/show/NCT01873287).

Epidemiology of Injuries in Ice Hockey

CONTEXT

Hockey is a skillful contact sport with an elevated injury risk at higher levels of play. An understanding of injury incidence, type, mechanism, and severity at various levels of competition aids the clinician treating these athletes. The purpose of this clinical review is to discuss the epidemiology of hockey injuries at various levels of participation, including youth, high school, junior, college, and professional.

EVIDENCE ACQUISITION

A literature search was performed by a review of PubMed, Embase, and Cochrane databases and included articles published from 1988 to 2017. Studies were included in this review if determined to be of high quality and containing injury data relevant to the levels of competition. Pertinent data regarding ice hockey injury epidemiology and prevention at various levels of competition were analyzed.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Youth, high school, junior, college, and professional hockey players have unique injury patterns. Injuries occur much more often in a game compared with a practice, and injury risk increases with each level of competition. Preventative measures, such as mandatory facial protection and delayed body checking in games until age 13 years, are proven strategies to reduce the risk of facial injury and concussion.

CONCLUSION

An understanding of common injury types and mechanisms according to age and level of play aids the clinician in diagnosis and management. This information can also guide preventative strategies in the areas of education, coaching, rule enforcement, rule modifications, equipment improvement, and sportsmanship.

What the research says about concussion risk factors and prevention strategies for youth sports: A scoping review of six commonly played sports

INTRODUCTION

Given the growing research on potential adverse outcomes related to concussion and other serious brain injuries and the increased susceptibility for concussion among youth athletes, primary prevention is vital to protect the health and safety of this population. The purpose of this study is to summarize the current research on risk factors and primary concussion prevention strategies focused on specific youth sports, and to identify research gaps.

METHODS

A literature search was conducted using six electronic databases. A scoping review method was used to identify studies that addressed risk factors or primary concussion prevention strategies focused on youth athletes (ages 5-18 years) in six sports (football, ice hockey, soccer, lacrosse, basketball, and wrestling).

RESULTS

Of the 18 publications identified, the publications focused on risk factors (N = 11), policy (N = 1), rule changes (N = 3), education (N = 2), equipment (N = 2), and playing technique (N = 0). Some articles had information related to multiple topics.

CONCLUSIONS

Current research on concussion prevention has primarily been focused on risk factors. There are a dearth of studies that examine primary concussion prevention in sports. When studies do exist, most focus on football and ice hockey. Only a small number of studies focus solely on risk factors or primary prevention in soccer, lacrosse, basketball, and wrestling-all sports in which concussions are common. Practical applications: This scoping review summarizes current research on concussion risk factors and primary prevention strategies in specific sports focused on youth athletes and identifies research gaps to help inform future efforts.

Proceedings from the Ice Hockey Summit III: Action on Concussion

The Ice Hockey Summit III provided updated scientific evidence on concussions in hockey to inform these five objectives: 1) describe sport-related concussion (SRC) epidemiology, 2) classify prevention strategies, 3) define objective, diagnostic tests, 4) identify treatment, and 5) integrate science and clinical care into prioritized action plans and policy. Our action plan evolved from 40 scientific presentations. The 155 attendees (physicians, athletic trainers, physical therapists, nurses, neuropsychologists, scientists, engineers, coaches, and officials) voted to prioritize these action items in the final Summit session. 1) Establish a national and international hockey data base for SRC at all levels, 2) eliminate body checking in Bantam youth hockey games, 3) expand a behavior modification program (Fair Play) to all youth hockey levels, 4) enforce game ejection penalties for fighting in Junior A and professional hockey leagues, 5) establish objective tests to diagnose concussion at point of care (POC), and 6) mandate baseline testing to improve concussion diagnosis for all age groups. Expedient implementation of the Summit III prioritized action items is necessary to reduce the risk, severity, and consequences of concussion in the sport of ice hockey.

Association of Dynamic Balance With Sports-Related Concussion: A Prospective Cohort Study

BACKGROUND

Concussion is one of the most common sports-related injuries, with little understood about the modifiable and nonmodifiable risk factors. Researchers have yet to evaluate the association between modifiable sensorimotor function variables and concussive injury.

PURPOSE

To investigate the association between dynamic balance performance, a discrete measure of sensorimotor function, and concussive injuries.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

A total of 109 elite male rugby union players were baseline tested in dynamic balance performance while wearing an inertial sensor and prospectively followed during the 2016-2017 rugby union season. The sample entropy of the inertial sensor gyroscope magnitude signal was derived to provide a discrete measure of dynamic balance performance. Logistic regression modeling was then used to investigate the association among the novel digital biomarker of balance performance, known risk factors of concussion (concussion history, age, and playing position), and subsequent concussive injury.

RESULTS

Participant demographic data (mean ± SD) were as follows: age, 22.6 ± 3.6 years; height, 185 ± 6.5 cm; weight, 98.9 ± 12.5 kg; body mass index, 28.9 ± 2.9 kg/m²; and leg length, 98.8 ± 5.5 cm. Of the 109 players, 44 (40.3%) had a history of concussion, while 21 (19.3%) sustained a concussion during the follow-up period. The receiver operating characteristic analysis for the anterior sample entropy demonstrated a statistically significant area under the curve (0.64; 95% CI, 0.52-0.76; P < .05), with the cutoff score of anterior sample entropy ≥1.2, which maximized the sensitivity (76.2%) and specificity (53.4%) for identifying individuals who subsequently sustained a concussion. Players with suboptimal balance performance at baseline were at a 2.81-greater odds (95% CI, 1.02-7.74) of sustaining a concussion during the rugby union season than were those with optimal balance performance, even when controlling for concussion history.

CONCLUSION

Rugby union players who possess poorer dynamic balance performance, as measured by a wearable inertial sensor during the Y balance test, have a 3-times-higher relative risk of sustaining a sports-related concussion, even when controlling for history of concussion. These findings have important implications for research and clinical practice, as it identifies a potential modifiable risk factor. Further research is required to investigate this association in a large cohort consisting of males and females across a range of sports.

Experimental Designs for Repeated Mild Traumatic Brain Injury: Challenges and Considerations

Mild traumatic brain injury (mild TBI) is a growing public concern, as evidence mounts that even brain injuries classified as "mild" can result in persistent neurological dysfunction. Multiple brain injuries heighten the likelihood of worsened or more prolonged symptomatology and may trigger long-term neurodegeneration. Animal models provide a logical platform to identify key parameters, such as loading forces, duration between injuries, and number of injuries, which contribute to additive or synergistic damage after repeated mild TBI. Despite the tremendous increase in research productivity in the field of repeated mild TBI, relatively few studies have been designed in such a way as to provide experimental-based insights into the dependence of cellular and functional outcomes on the prescribed parameters of mild TBI. In this review, we summarize how standard models of TBI have been adapted to produce mild TBI and highlight commonly observed aspects of neuropathology replicated in rodent models of mild TBI. The complexity of designing studies of repeated TBI is discussed, including challenges of incorporating appropriate control groups, informative experimental design, and relevant outcome measures. We then feature studies that provide a well-controlled, within-study design varying either the number of injuries or the interinjury interval. Harnessing the power of experimental models of TBI to elucidate which injury parameters are critical contributors to acute and chronic damage after repeated injury can further efforts at prevention and provide improved models for testing mechanisms and therapeutic interventions.

Physical activity and concussion risk in youth ice hockey players: pooled prospective injury surveillance cohorts from Canada

OBJECTIVE

To examine the association between meeting physical activity (PA) volume recommendations and concussion rates in male ice hockey players aged 11-17 years.

DESIGN

Pooled prospective injury surveillance cohort data from the 2011-2012, 2013-2014 and 2014-2015 youth ice hockey seasons.

PARTICIPANTS

Male Alberta-based Pee Wee (aged 11-12 years), Bantam (aged 13-14 years) and Midget (aged 15-17 years) ice hockey players participating in any of the three cohorts were eligible (n=1726). A total of 1208 players were included after the exclusion criteria were applied (ie, players with new/unhealed injuries within 6 weeks of study entry, missing 6-week PA history questionnaires, missing game and/or practice participation exposure hours, players who sustained concussions when no participation exposure hours were collected).

OUTCOME MEASURES

Dependent variable: medically diagnosed concussion. Independent variable: whether or not players' self-reported history of PA (ie, hours of physical education and extracurricular sport participation) met the Canadian Society of Exercise Physiology and Public Health Agency of Canada recommendation of one hour daily during the 6 weeks prior to study entry (ie, 42 hours or more).

RESULTS

The PA volume recommendations were met by 65.05% of players who subsequently sustained concussions, and 75.34% of players who did not sustain concussions. The concussion incidence rate ratios (IRR) reflect higher concussion rates in players who did not meet the PA volume recommendations vs. players who met the PA volume recommendations among Pee Wee players (IRR 2.94 95% CI 1.30 to 6.64), Bantam players (IRR 2.18, 95% CI 1.21 to 3.93) and non-elite players aged 11-14 years (IRR 2.45, 95% CI 1.33 to 4.51).

CONCLUSION AND RELEVANCE

The concussion rate of players who did not meet the Canadian PA volume recommendations was more than twice the concussion rate of players who met recommendations among male Pee Wee players, Bantam players and non-elite level players. Further exploration of the impact of public health PA recommendations in a sport injury prevention context is warranted.

Primary prevention of contact sports-related concussions in amateur athletes: a systematic review from the Eastern Association for the Surgery of Trauma

BACKGROUND

Awareness of the magnitude of contact sports-related concussions has risen exponentially in recent years. Our objective is to conduct a prospectively registered systematic review of the scientific evidence regarding interventions to prevent contact sports-related concussions.

METHODS

Using the Grading of Recommendations Assessment, Development, and Evaluation methodology, we performed a systematic review of the literature to answer seven population, intervention, comparator, and outcomes (PICO) questions regarding concussion education, head protective equipment, rules prohibiting high-risk activity and neck strengthening exercise for prevention of contact sports-related concussion in pediatric and adult amateur athletes. A query of MEDLINE, PubMed, Scopus, Cumulative Index of Nursing and Allied Health Literature, and Embase was performed. Letters to the editor, case reports, book chapters, and review articles were excluded, and all articles reviewed were written in English.

RESULTS

Thirty-one studies met the inclusion criteria and were applicable to our PICO questions. Conditional recommendations are made supporting preventive interventions concussion education and rules prohibiting high-risk activity for both pediatric and adult amateur athletes and neck strengthening exercise in adult amateur athletes. Strong recommendations are supported for head protective equipment in both pediatric and adult amateur athletes. Strong recommendations regarding newer football helmet technology in adult amateur athletes and rules governing the implementation of body-checking in youth ice hockey are supported.

CONCLUSION

Despite increasing scientific attention to sports-related concussion, studies evaluating preventive interventions remain relatively sparse. This systematic review serves as a call to focus research on primary prevention strategies for sports-related concussion.

LEVEL OF EVIDENCE

IV.

PROSPERO REGISTRATION NUMBER

#42016043019.

Injury Recurrence Among High School Athletes in the United States: A Decade of Patterns and Trends, 2005-2006 Through 2015-2016

Background

As participation in high school athletics increases, so does the number of adolescents experiencing sports-related injury. Understanding injury patterns is an important component to developing and evaluating prevention and rehabilitation programs.

Purpose

To analyze recurrent injury rates and patterns among high school athletes, to compare recurrent injuries with new injuries, and to evaluate injury trends over time.

Study Design

Descriptive epidemiology study.

Methods

High school sports injury data on 24 sports were collected from 2005-2006 through 2015-2016 via the High School RIO (Reporting Information Online) surveillance system. Injury rates were calculated as number of injuries per 10,000 athletic exposures (AEs). Injury rate ratios and injury proportion ratios (IPRs) were calculated to compare differences among subgroups.

Results

Overall, 78,005 injuries were sustained during 40,195,806 AEs, for an injury rate of 19.41 per 10,000 AEs. Of these, 69,821 (89.5%) were new injuries, and 8184 (10.5%) were recurrent. The ankle was the most commonly injured body part among recurrent injuries, while the head/face was the most common body part that sustained new injuries. Ligament sprains were more often recurrent, while concussions were more commonly diagnosed as new, although concussions represented 16.7% of recurrent injuries. Trends for recurrent injuries over time were relatively stable. The proportion of athletes who had >3 weeks of time loss or medical disqualification (15.8% vs 13.3%; IPR, 1.19; 95% CI, 1.13-1.26) or who voluntarily withdrew from sport (2.5% vs 1.1%; IPR, 2.33; 95% CI, 2.00-2.73) was significantly greater for recurrent injuries than new injuries. Furthermore, a greater proportion of recurrent injuries resulted in surgery (8.1% vs 6.0%; IPR, 1.34; 95% CI, 1.24-1.46).

Conclusion

Although only 10.5% of all injuries were recurrent, they more frequently resulted in missing >3 weeks of playing time and were more often managed surgically when compared with new injuries. The rate of recurrent injuries has not increased over the past decade.

Cervical spine trauma: prevention strategies

Participation in any sport activity carries risk of cervical spine trauma, but certain activities have a higher risk than others, and hence, demand concerted efforts in developing prevention strategies. Prevention often includes efforts surrounding education of stakeholders, creating or modifying rules, and specific policies adopted for decreasing such risk. Stakeholders include sport clinicians, participants, coaches, parents, league administrators, officials, and the public. Thus, both athlete-specific and setting-specific factors must be considered and controlled to the extent possible for a multipronged approach for decreasing cervical spine injury risk. The effectiveness of certain strategies put into place in collision sports, such as American football, rugby, and ice hockey, is reviewed to illustrate this approach. Some research evidence exists that either has informed a strategy, or validated its effectiveness after the fact. More research of a higher level needs to be conducted in all sports to continue to contain the risk of cervical spine trauma to the fullest extent possible.

The Impact of Body Checking on Youth Ice Hockey Injuries

Background

Body checking is a common cause of youth ice hockey injuries. Consequently, USA Hockey raised the minimum age at which body checking is permitted from the Pee Wee level (11-12 years old) to the Bantam level (13-14 years old) in 2011.

Purpose/Hypothesis

The purpose of this investigation was to determine the impact of body checking on the distribution of injuries reported in youth ice hockey players. We hypothesized that the elimination of body checking at the Pee Wee level would lower the frequency of serious injuries, particularly concussions.

Study Design

Descriptive epidemiology study.

Methods

Injury data from the National Electronic Injury Surveillance System (NEISS), a United States Consumer Product Safety Commission database, were analyzed for Pee Wee and Bantam players between January 1, 2008 and December 31, 2010 and again between January 1, 2013 and December 31, 2015. Data on the location of injury, diagnosis, and mechanism of injury were collected. The location of injury was categorized into 4 groups: head and neck, upper extremity, lower extremity, and core. Diagnoses investigated included concussions, fractures, lacerations, strains or sprains, internal organ injuries, and other. The mechanism of injury was broken down into 2 categories: checking and other.

Results

Between the 2008-2010 and 2013-2015 seasons, overall injuries decreased by 16.6% among Pee Wee players, with injuries caused by body checking decreasing by 38.2% (P = .012). There was a significant change in the distribution of diagnoses in the Pee Wee age group during this time frame (P = .007): strains or sprains, internal organ injuries, and fractures decreased in frequency, while the number of concussions increased by 50.0%. In the Bantam age group, recorded injuries decreased by 6.8%, and there was no change in the distribution of the location of injury, diagnosis, or mechanism of injury (P > .05).

Conclusion

There was an observed reduction in the total number, mechanism, and type of injuries when body checking was eliminated from the Pee Wee level. There was, however, an unexpected increase in the number of concussions.

Evidence in support of the call to ban the tackle and harmful contact in school rugby: a response to World Rugby

In a paper published in BJSM (June 2016), World Rugby employees Ross Tucker and Martin Raftery and a third coauthor Evert Verhagen took issue with the recent call to ban tackling in school rugby in the UK and Ireland. That call (to ban tackling) was supported by a systematic review published in BJSM Tucker et al claim that: (1) the mechanisms and risk factors for injury along with the incidence and severity of injury in youth rugby union have not been thoroughly identified or understood; (2) rugby players are at no greater risk of injury than other sports people, (3) this is particularly the case for children under 15 years and (4) removing the opportunity to learn the tackle from school pupils might increase rates of injuries. They conclude that a ban 'may be unnecessary and may also lead to unintended consequences such as an increase in the risk of injury later in participation.' Here we aim to rebut the case by Tucker et al We share new research that extends the findings of our original systematic review and meta-analysis. A cautionary approach requires the removal of the tackle from school rugby as the quickest and most effective method of reducing high injury rates in youth rugby, a public health priority.

Injury Surveillance of Head, Neck, and Facial Injuries in Collegiate Ice Hockey Players, 2009-2010 Through 2013-2014 Academic Years

CONTEXT

  Ice hockey is a high-speed, full-contact sport with a high risk of head/face/neck (HFN) injuries. However, men's and women's ice hockey differ; checking is allowed only among men.

OBJECTIVES

  To describe the epidemiology of HFN injuries in collegiate men's and women's ice hockey during the 2009-2010 through 2013-2014 academic years.

DESIGN

  Descriptive epidemiology study.

SETTING

  Ice hockey data from the National Collegiate Athletic Association (NCAA) Injury Surveillance Program during the 2009-2010 through 2013-2014 academic years.

PATIENTS OR OTHER PARTICIPANTS

  Fifty-seven men's and 26 women's collegiate ice hockey programs from all NCAA divisions provided 106 and 51 team-seasons of data, respectively.

MAIN OUTCOME MEASURE(S)

  Injury rates per 1000 athlete-exposures and rate ratios with 95% confidence intervals (CIs).

RESULTS

  The NCAA Injury Surveillance Program reported 496 and 131 HFN injuries in men's and women's ice hockey, respectively. The HFN injury rate was higher in men than in women (1.75 versus 1.16/1000 athlete-exposures; incidence rate ratio = 1.51; 95% CI = 1.25, 1.84). The proportion of HFN injuries from checking was higher in men than in women for competitions (38.5% versus 13.6%; injury proportion ratio = 2.82; 95% CI = 1.64, 4.85) and practices (21.9% versus 2.3%; injury proportion ratio = 9.41; 95% CI = 1.31, 67.69). The most common HFN injury diagnosis was concussion; most concussions occurred in men's competitions from player contact while checking (25.9%). Player contact during general play comprised the largest proportion of concussions in men's practices (25.9%), women's competitions (25.0%), and women's practices (24.0%). While 166 lacerations were reported in men, none were reported in women. In men, most lacerations occurred from player contact during checking in competitions (41.8%) and player contact during general play in practices (15.0%).

CONCLUSIONS

  A larger proportion of HFN injuries in ice hockey occurred during checking in men versus women. Concussion was the most common HFN injury and was most often due to player contact. Lacerations were reported only among men and were mostly due to checking. Injury-prevention programs should aim to reduce checking-related injuries.

Epidemiology of Sport-Related Concussions in High School Athletes: National Athletic Treatment, Injury and Outcomes Network (NATION), 2011-2012 Through 2013-2014

CONTEXT

Sports participation is one of the leading causes of concussions among nearly 8 million US high school student-athletes.

OBJECTIVE

To describe the epidemiology of sport-related concussion (SRC) in 27 high school sports during the 2011-2012 through 2013-2014 academic years.

DESIGN

Descriptive epidemiology study.

SETTING

Aggregate injury and exposure data from 27 sports in 147 high schools in the National Athletic Treatment, Injury and Outcomes Network (NATION).

PATIENTS OR OTHER PARTICIPANTS

Boy and girl high school athletes during the 2011-2012 through 2013-2014 academic years.

MAIN OUTCOME MEASURE(S)

Sport-related concussion counts, percentages, rates per 10 000 athlete-exposures (AEs), rate ratios (RRs), and injury proportion ratios (IPRs) were reported with 95% confidence intervals (CIs). Rate ratios and IPRs with 95% CIs not containing 1.0 were considered significant.

RESULTS

Overall, 2004 SRCs were reported among 27 high school sports, for a rate of 3.89 per 10 000 AEs. Football had the highest SRC rate (9.21/10 000 AEs), followed by boys' lacrosse (6.65/10 000 AEs) and girls' soccer (6.11/10 000 AEs). The SRC rate was higher in competition than in practice (RR = 3.30; 95% CI = 3.02, 3.60). Among sex-comparable sports, the SRC rate was higher in girls than in boys (RR = 1.56; 95% CI = 1.34, 1.81); however, the proportion of SRCs due to player-to-player contact was higher in boys than in girls (IPR = 1.48; 95% CI = 1.27, 1.73). Common symptoms reported among all athletes with SRCs were headache (94.7%), dizziness (74.8%), and difficulty concentrating (61.0%). Only 0.8% of players with SRCs returned to play within 24 hours. The majority of athletes with SRCs (65.8%) returned to play between 7 and 28 days. More players had symptoms resolve after 7 days (48.8%) than less than a week (40.7%).

CONCLUSIONS

Our findings provide updated high school SRC incidence estimates and further evidence of sex differences in reported SRCs. Few athletes with SRCs returned to play within 24 hours or a week. Most injured players returned after 7 days, despite a smaller proportion having symptoms resolve within a week.

A Multifactorial Approach to Sport-Related Concussion Prevention and Education: Application of the Socioecological Framework

OBJECTIVE

To offer an overview of sport-related concussion (SRC) prevention and education strategies in the context of the socioecological framework (SEF). Athletic trainers (ATs) will understand the many factors that interact to influence SRC prevention and the implications of these interactions for effective SRC education.

BACKGROUND

Concussion is a complex injury that is challenging to identify and manage, particularly when athletes fail to disclose symptoms to their health care providers. Education is 1 strategy for increasing disclosure. However, limited information addresses how ATs can integrate the many factors that may influence the effectiveness of SRC education into their specific settings. Public health models provide an example through the SEF, which highlights the interplay among various levels of society and sport that can facilitate SRC prevention strategies, including education.

DESCRIPTION

For ATs to develop appropriate SRC prevention strategies, a framework for application is needed. A growing body of information concerning SRC prevention indicates that knowledge alone is insufficient to change concussion-related behaviors. The SEF allows this information to be considered at levels such as policy and societal, community, interpersonal (relationships), and intrapersonal (athlete). The use of such a framework will facilitate more comprehensive SRC prevention efforts that can be applied in all athletic training practice settings. Clinical Applications: Athletic trainers can use this information as they plan SRC prevention strategies in their specific settings. This approach will aid in addressing the layers of complexity that exist when developing a concussion-management policy and plan.

Development of the Sports Organization Concussion Risk Assessment Tool (SOCRAT)

OBJECTIVE

In this paper, we describe the development of a novel tool-the Sports Organization Concussion Risk Assessment Tool (SOCRAT)-to assist sport organizations in assessing the overall risk of concussion at a team level by identifying key risk factors.

METHODS

We first conducted a literature review to identify risk factors of concussion using ice hockey as a model. We then developed an algorithm by combining the severity and the probability of occurrence of concussions of the identified risk factors by adapting a risk assessment tool commonly used in engineering applications.

RESULTS

The following risk factors for ice hockey were identified: age, history of previous concussions, previous body checking experience, allowance of body checking, type of helmet worn and the game or practice environment. These risk factors were incorporated into the algorithm, resulting in an individual risk priority number (RPN) for each risk factor and an overall RPN that provides an estimate of the risk in the given circumstances.

CONCLUSION

The SOCRAT can be used to analyse how different risk factors contribute to the overall risk of concussion. The tool may be tailored to organizations to provide: (1) an RPN for each risk factor and (2) an overall RPN that takes into account all the risk factors. Further work is needed to validate the tool based on real data.

Mechanisms and Factors Associated With Tackle-Related Injuries in South African Youth Rugby Union Players

BACKGROUND

The majority of injuries in rugby union occur during tackle events. The mechanisms and causes of these injuries are well established in senior rugby union.

PURPOSE

To use information from an injury database and assess video footage of tackle-related injuries in youth rugby union matches to identify environmental factors and mechanisms that are potentially confounding to these injuries.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

Injury surveillance was conducted at the under-18 Craven Week rugby tournament. Tackle-related injury information was used to identify injury events in match video footage (role-matched noninjury tackle events were identified for the cohort of injured players). Events were coded using match situational variables (precontact, contact, and postcontact). Relative risk ratio (RRR; ratio of probability of an injury or noninjury outcome occurring when a characteristic was observed) was reported by use of logistic regression.

RESULTS

In comparison with the first quarter, injury risk was greater in the third (RRR = 9.75 [95% CI, 1.71-55.64]; P = .010) and fourth quarters (RRR = 6.97 [95% CI, 1.09-44.57]; P = .040) for ball carriers and in the fourth quarter (RRR = 9.63 [95% CI, 1.94-47.79]; P = .006) for tacklers. Ball carriers were less likely to be injured when they were aware of impending contact (RRR = 0.14 [95% CI, 0.03-0.66]; P = .012) or when they executed a moderate fend (hand-off) (RRR = 0.22 [95% CI, 0.06-0.84]; P = .026). Tacklers were less likely to be injured when performing shoulder tackles (same side as leading leg) in comparison to an arm-only tackle (RRR = 0.02 [95% CI, 0.001-0.79]; P = .037). Ball carriers (RRR = 0.09 [95% CI, 0.01-0.89]; P = .040) and tacklers (RRR = 0.02 [95% CI, 0.001-0.32]; P =.006) were less likely to be injured when initial contact was made with the tackler's shoulder/arm instead of his head/neck.

CONCLUSION

The relative risk of tackle-related injury was higher toward the end of matches. Incorrect technique may contribute to increased injury risk. Implementing recovery strategies between matches, training safe and effective techniques, and improving levels of conditioning may counter the negative effects of fatigue. These findings may assist stakeholders in youth rugby to formulate injury prevention strategies and may improve the preparation of field-side medical staff for managing tackle-related injuries at these or similar tournaments.

The Effect of the "Zero Tolerance for Head Contact" Rule Change on the Risk of Concussions in Youth Ice Hockey Players

BACKGROUND

Ice hockey is a popular winter sport in Canada. Concussions account for the greatest proportion of all injuries in youth ice hockey. In 2011, a policy change enforcing "zero tolerance for head contact" was implemented in all leagues in Canada.

PURPOSE

To determine if the risk of game-related concussions and more severe concussions (ie, resulting in >10 days of time loss) and the mechanisms of a concussion differed for Pee Wee class (ages 11-12 years) and Bantam class (ages 13-14 years) players after the 2011 "zero tolerance for head contact" policy change compared with players in similar divisions before the policy change.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The retrospective cohort included Pee Wee (most elite 70%, 2007-2008; n = 891) and Bantam (most elite 30%, 2008-2009; n = 378) players before the rule change and Pee Wee (2011-2012; n = 588) and Bantam (2011-2012; n = 242) players in the same levels of play after the policy change. Suspected concussions were identified by a team designate and referred to a sport medicine physician for diagnosis. Incidence rate ratios (IRRs) were estimated based on multiple Poisson regression analysis, controlling for clustering by team and other important covariates and offset by game-exposure hours. Incidence rates based on the mechanisms of a concussion were estimated based on univariate Poisson regression analysis.

RESULTS

The risk of game-related concussions increased after the head contact rule in Pee Wee (IRR, 1.85; 95% CI, 1.20-2.86) and Bantam (IRR, 2.48; 95% CI, 1.17-5.24) players. The risk of more severe concussions increased after the head contact rule in Pee Wee (IRR, 4.12; 95% CI, 2.00-8.50) and Bantam (IRR, 7.91; 95% CI, 3.13-19.94) players. The rates of concussions due to body checking and direct head contact increased after the rule change.

CONCLUSION

The "zero tolerance for head contact" policy change did not reduce the risk of game-related concussions in Pee Wee or Bantam class ice hockey players. Increased concussion awareness and education after the policy change may have contributed to the increased risk of concussions found after the policy change.