Performance After Concussion in National Hockey League Players

ContextConcussions in ice hockey players are an interesting area of study due to the fast-paced and high-impact nature of the sport. Recently, researchers have focused on player performance after return from concussion to evaluate subclinical deficits that were previously missed.ObjectiveTo examine National Hockey League (NHL) player performance from 2013 to 2019 and compare performance before a concussion with performance immediately after recovering to assess the current NHL return-to-play protocol.DesignCross-sectional study.SettingThe NHL Injury Viz and sports reporting websites.Patients or Other ParticipantsPlayers in the NHL who sustained concussions from 2013 to 2019.Main Outcome Measure(s)Goals, assists, points, plus-minus, time on ice (TOI), and hits.ResultsWhen goals, assists, points, plus-minus, TOI, and hits were examined, only TOI was different after the players returned from injury, and this TOI difference was not substantively important.ConclusionsAfter concussion, NHL player performance did not change.     

Long-Term Influence of Concussion on Cardio-Autonomic Function in Adolescent Hockey Players

ContextConcussion may negatively influence cardiovascular function and the autonomic nervous system, defined by alteration in heart rate variability (HRV). Differences in HRV most commonly emerge during a physical challenge, such as the final steps of the return-to-sport progression.ObjectiveTo assess the effect of concussion history on aspects of cardio-autonomic function during recovery from a bout of submaximal exercise in adolescent male hockey athletes.DesignCase-control study.SettingResearch laboratory.Patients or Other ParticipantsThirty-three male athletes participating in Midget-AAA hockey were divided into those with (n = 15; age = 16 ± 1 years, height = 1.78 ± 0.06 m, mass = 73.9 ± 7.4 kg, 10.5 ± 1.6 years of sport experience, 25.2 ± 18.3 months since last injury) or without (n = 18; age = 16 ± 1 years, height = 1.78 ± 0.05 m, mass = 74.8 ± 7.6 kg, 10.6 ± 1.9 years of sport experience) a concussion history. Those with a concussion history were binned on total count: 1 concussion or 2 or more concussions.Intervention(s)All athletes underwent 5 minutes of resting HRV assessment, followed by 20 minutes of aerobic exercise at 60% to 70% of their maximal target heart rate and a 9-minute, postexercise HRV assessment.Main Outcome Measure(s)Heart rate variability measures of mean NN interval, root mean square of successive differences, and standard deviation of NN interval (SDNN).ResultsGroup demographic characteristics were not different. When the control and concussed groups were compared, group and time main effects for heart rate recovery, root mean square of successive differences, and SDNN (P values < .01), and an interaction effect for SDNN (P < .05) were demonstrated. Recovery trends for each group indicated that a history of 2 or more concussions may negatively affect cardio-autonomic recovery postexercise.ConclusionsOur findings suggest that those with more than 1 previous concussion may be associated with a greater risk for long-term dysautonomia. Future use of HRV may provide clinicians with objective guidelines for concussion-management and safe return-to-participation protocols.     

Youth Soccer Parents’ Perceptions of Long-Term Effects of Concussion

ABSTRACT

Increased focus on sports-related concussion (SRC) in football in the media, and mandatory concussion education for parents of youth sport athletes, may result in parental concern that youth athletes will experience long-term effects from concussion. We sought to identify beliefs about long-term effects of concussion in parents of youth soccer athletes. Four hundred and eleven parents from soccer leagues in three states completed a survey assessing parents’ perceptions and knowledge of long-term effects of SRC. Nearly all youth soccer parents surveyed (96.5%) believe there are long-term effects from SRCs, 76% reported concern their child would sustain a concussion, and 71% had talked with their child about concussion symptoms/reporting. Parents ranked tackle football as having the highest risk for concussion, followed by soccer, ice hockey, cheerleading, and lacrosse. Parents of children that had previously sustained a concussion were 8.3x more likely to be concerned their child would sustain a concussion, and parents with a personal history of concussion were 2x more likely to consider not allowing their child to participate in youth sports. There are wide-spread beliefs among youth soccer parents regarding long-term effects of SRCs, and concerns their children will sustain concussions while participating in youth sports.     

Concussion history and postconcussion neurocognitive performance and symptoms in collegiate athletes

CONTEXT: Athletes are at an inherent risk for sustaining concussions. Research examining the long-term consequences of sport-related concussion has been inconsistent in demonstrating lingering neurocognitive decrements that may be associated with a previous history of concussion. OBJECTIVE: To determine the relationship between concussion history and postconcussion neurocognitive performance and symptoms in collegiate athletes. DESIGN: Repeated-measures design. SETTING: Multi-center analysis of collegiate athletes. PATIENTS OR OTHER PARTICIPANTS: Fifty-seven concussed collegiate athletes (36 without concussion history, 21 with a history of 2 or more concussions). INTERVENTION(S): All subjects were administered an Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) neurocognitive test battery, which measures verbal memory, visual memory, reaction time, and visual processing speed and 22 concussion symptoms. MAIN OUTCOME MEASURE(S): Subjects who sustained a concussion were administered 2 follow-up tests at days 1 and 5 postinjury. Independent variables were history of concussion (no history of concussion, 2 or more concussions) and time (baseline, day 1 postconcussion, or day 5 postconcussion). RESULTS: A within-subjects effect (time) on ImPACT performance (P < .001), a between-subjects multivariate effect of group (P < .001), and a group-by-time interaction (P = .034) were noted. Athletes with a concussion history performed significantly worse on verbal memory (P = .01) and reaction time (P = .023) at day 5 postconcussion compared with athletes who did not report a previous concussion. No significant group differences were seen at day 5 postinjury on visual memory (P = .167), processing speed (P = .179), or total concussion symptoms (P = .87). CONCLUSIONS: Concussed collegiate athletes with a history of 2 or more concussions took longer to recover verbal memory and reaction time than athletes without a history of concussion.     

Assessing the enduring residual neuropsychological effects of head trauma in college athletes who participate in contact sports.

The present study examined the enduring residual neuropsychological effects of head trauma in college athletes using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Postconcussion Syndrome Checklist, and the Stroop task. Based on a brief self-report concussion history survey, male and female athletes who participated in ice hockey, field hockey, lacrosse, and/or soccer were assigned to one of three concussion-history conditions: Non-concussed, Non-recent concussed (i.e., more than 2 years since last concussion), or Recent concussed (i.e., 2 years or less since last concussion). A fourth group of subjects consisting of non-concussed/non-athletes served in the control condition. Group differences emerged on the RBANS when immediate memory, delayed memory, and total scores were analyzed. Specifically, recent concussed athletes and, surprisingly, non-concussed athletes scored lower than control subjects in the two memory domains, whereas all three athlete groups had lower total RBANS scores than those of control subjects. Moreover, recent concussed athletes not only had lower immediate memory scores than control subjects, but also were impaired relative to non-recent concussed athlete subjects in this memory domain. No group differences were detected on the Stroop task or on the Postconcussion Syndrome Checklist. Interestingly, however, the severity of the Postconcussion Syndrome Checklist scores for the two athlete-concussed groups, taken in aggregate, correlated negatively with RBANS scores for attention (r = -.65) and delayed memory (r = -.61), and with the total RBANS score (r = -.59). In recent concussed athletes, lower delayed memory scores correlated with more severe Postconcussion Symptom Checklist scores (r = -.90), while more severe/higher number of concussions correlated with increased processing speed on the Stroop interference task (r = .90). These findings indicate that recent head injury produces alterations in neuropsychological function, especially that of memory, that resolve with time. More provocatively, the data also suggest that participation in contact sports may produce sub-clinical cognitive impairments in the absence of a diagnosable concussion presumably resulting from the cumulative consequences produced by multiple mild head trauma.     

Comparison of Ice Hockey Goaltender Helmets for Concussion Type Impacts

Concussions are among the most common injuries sustained by ice hockey goaltenders and can result from collisions, falls and puck impacts. However, ice hockey goaltender helmet certification standards solely involve drop tests to a rigid surface. This study examined how the design characteristics of different ice hockey goaltender helmets affect head kinematics and brain strain for the three most common impact events associated with concussion for goaltenders. A NOCSAE headform was impacted under conditions representing falls, puck impacts and shoulder collisions while wearing three different types of ice hockey goaltender helmet models. Resulting linear and rotational acceleration as well as maximum principal strain were measured for each impact condition. The results indicate that a thick liner and stiff shell material are desirable design characteristics for falls and puck impacts to reduce head kinematic and brain tissue responses. However for collisions, the shoulder being more compliant than the materials of the helmet causes insufficient compression of the helmet materials and minimizing any potential performance differences. This suggests that current ice hockey goaltender helmets can be optimized for protection against falls and puck impacts. However, given collisions are the leading cause of concussion for ice hockey goaltenders and the tested helmets provided little to no protection, a clear opportunity exists to design new goaltender helmets which can better protect ice hockey goaltenders from collisions.     

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

ContextThe National Collegiate Athletic Association has supported men''s ice hockey, a distinct sport that mandates high-velocity gamesmanship, since 1974.BackgroundInjury surveillance systems are designed to identify evolving injury trends and their temporal qualities. Continual monitoring of collegiate men''s ice hockey athletes remains essential.MethodsExposure and injury data collected in the National Collegiate Athletic Association 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 (IRR) were used to examine differential injury rates.ResultsThe overall injury rate was 7.65 per 1000 athlete-exposures. Injuries from competition occurred at a rate nearly 7 times that from practice injuries (IRR = 6.54, 95% CI = 6.08, 7.04). The most common specific injury diagnoses were concussions (9.6%), acromioclavicular sprains (7.3%), and medial collateral ligament tears (3.7%).SummaryInjury rates by event type and season segment were higher than previously reported. Contusions accounted for nearly a quarter of all injuries, and acromioclavicular sprain rates increased notably across the study period.     

Head-Impact Mechanisms in Men's and Women's Collegiate Ice Hockey

Context:

Concussion injury rates in men''s and women''s ice hockey are reported to be among the highest of all collegiate sports. Quantification of the frequency of head impacts and the magnitude of head acceleration as a function of the different impact mechanisms (eg, head contact with the ice) that occur in ice hockey could provide a better understanding of this high injury rate.

Objective:

To quantify and compare the per-game frequency and magnitude of head impacts associated with various impact mechanisms in men''s and women''s collegiate ice hockey players.

Design:

Cohort study.

Setting:

Collegiate ice hockey rink.

Patients or Other Participants:

Twenty-three men and 31 women from 2 National Collegiate Athletic Association Division I ice hockey teams.

Main Outcome Measure(s):

We analyzed magnitude and frequency (per game) of head impacts per player among impact mechanisms and between sexes using generalized mixed linear models and generalized estimating equations to account for repeated measures within players.

Intervention(s):

Participants wore helmets instrumented with accelerometers to allow us to collect biomechanical measures of head impacts sustained during play. Video footage from 53 games was synchronized with the biomechanical data. Head impacts were classified into 8 categories: contact with another player; the ice, boards or glass, stick, puck, or goal; indirect contact; and contact from celebrating.

Results:

For men and women, contact with another player was the most frequent impact mechanism, and contact with the ice generated the greatest-magnitude head accelerations. The men had higher per-game frequencies of head impacts from contact with another player and contact with the boards than did the women (P < .001), and these impacts were greater in peak rotational acceleration (P = .027).

Conclusions:

Identifying the impact mechanisms in collegiate ice hockey that result in frequent and high-magnitude head impacts will provide us with data that may improve our understanding of the high rate of concussion in the sport and inform injury-prevention strategies.Key Words: impact biomechanics, sport, concussion, sex

Key Points

• The most frequent head-impact mechanism in both men''s and women''s collegiate ice hockey was contact with another player. Contact with the ice was the mechanism that resulted in head impacts with the greatest magnitude.
• Male collegiate ice hockey players experienced head impacts from contact with another player and contact with the boards more frequently than did female players, and these impacts were generally of greater magnitude.

Ice hockey is a high-intensity, high-speed collision sport in which most injuries are caused by blunt trauma or direct contact with another player or object as opposed to overuse injuries.¹ High rates of injury have been reported in both men''s and women''s collegiate ice hockey (5.95/1000 and 5.12/1000 athlete-exposures [AEs], respectively), and the most common injury in both populations is concussion.² The rate of concussion has been reported to be higher in women''s ice hockey (0.82/1000 AEs) than in men''s (0.72/1000 AEs), but the reasons for this are not well understood.² Concussions are usually attributed to a direct impact to the head but can also be caused by an impact to the body that results in an acceleration of the head.³ The high rate of injury, including concussions, in ice hockey can be attributed to the unique factors of the game: the playing area is made of solid ice and enveloped by rigid boards, players manipulate pucks that, when shot, can exceed speeds of 80 mph (117 kph), and players travel at speeds of up to 30 mph (44 kph) and purposefully collide with opponents.^4,5 These factors allow for a number of different head-impact mechanisms, or circumstances in which a head impact occurs (head contact with ice, boards, etc), in ice hockey.Currently, data quantifying the biomechanics of head impacts as a function of the different impact mechanisms that occur in ice hockey are lacking. Previous authors^6,7 have quantified the frequency and magnitude of head impacts in cohorts of male and female hockey players at different levels of play using the Head Impact Telemetry (HIT) System (Simbex, Lebanon, NH). The HIT System measures and records biomechanical data from head impacts, including the linear and rotational acceleration of the head, impact duration, and impact location on the helmet.^5–19 These studies have provided valuable information on individual players'' exposure to head impacts but did not identify or examine the relationship with mechanisms of impact. Other researchers^2,4,20–22 have reported injury epidemiology, including diagnosed concussions, by specific injury mechanisms in collegiate ice hockey. Agel et al^20,21 used the National Collegiate Athletic Association (NCAA) Injury Surveillance System to report concussion mechanisms in collegiate men and women. Diagnosed concussions were classified into 1 of 7 mechanisms: contact with another player, contact with the ice surface, contact with the boards or glass, contact with the goal, contact with the stick, contact with the puck, or no apparent contact. Another author²³ classified injury mechanisms in National Hockey League players by reviewing video footage from games in which diagnosed concussions occurred. The most common mechanism that resulted in diagnosed concussions for both studies was player-to-player contact.^20,21,23 Although these assessments provided important information on injury and concussion mechanisms in ice hockey, the collection and analysis of the impact biomechanics that resulted from these mechanisms were beyond the scope of the study designs. Synchronizing video with the biomechanics of head impacts would provide a quantitative approach to evaluating head impact mechanisms and biomechanics.The aim of our study was to quantify and compare the frequency and magnitude of head impacts associated with various impact mechanisms in men''s and women''s collegiate ice hockey players. We accomplished this by synchronizing video footage from games with biomechanical data from the HIT System. We hypothesized that the frequency and magnitude of head impacts would differ among the various head-impact mechanisms and that sex would be a significant factor in both frequency and magnitude.     

Factors Associated With Concussion Nondisclosure in Collegiate Student-Athletes

ContextMandated concussion education has aimed to improve student-athlete knowledge; however, some collegiate student-athletes continue to not disclose concussion. Concussion knowledge may not be the only factor influencing reporting, as student-athlete sex, sport, and pressure from external stakeholders (eg, coaches, teammates, fans, parents or family) have all been documented as influencing collegiate concussion-reporting behavior.ObjectiveTo examine factors associated with concussion nondisclosure in collegiate student-athletes.DesignCross-sectional study.SettingFour National Collegiate Athletic Association Division I and two Division II universities.Patients or Other ParticipantsA total of 1125 collegiate student-athletes completed the survey, and 741 provided viable responses and were included for data analysis.Main Outcome Measure(s)We used a 10- to 15-minute electronic or paper-and-pencil survey that asked about personal and sport demographics, diagnosed concussions and nondisclosed concussion history, concussion knowledge, and level of agreement regarding pressure to play after a head impact experienced during collegiate sport participation. Significant univariable factors were entered into a multivariable logistic regression analysis.ResultsSex (P = .005), sport-risk type (P < .001), diagnosed concussion history (P < .001), concussion knowledge (P = .017), and pressure from coaches (P < .001), teammates (P < .001), fans (P = .024), and parents or family (P = .003) were factors associated with concussion nondisclosure in individual univariable logistic regressions. After we conducted multivariable analyses, male sex (P = .001), high concussion-risk sport participation (P = .048), diagnosed concussion history (P < .001), increased concussion knowledge (P = .013), and experiencing pressure from coaches to continue playing after sustaining a hit to the head (P = .002) were factors associated with concussion nondisclosure in collegiate student-athletes.ConclusionsOur results suggest that concussion-education programs should go beyond the identification of signs and symptoms to include the dangers of continuing to play, long-term consequences, and transparency about concussion protocols. Comprehensive concussion-education programs should involve coaches and athletes to improve the reporting culture.     

Ice Hockey Injuries in a Japanese Elite Team: A 3-Year Prospective Study

Context:

As the Asian Ice Hockey League gradually expands and becomes more competitive, ice hockey-related injuries may increase. However, no reports have been published on ice hockey injuries in Japan, including the method of injury and the daily supervision of the players during the regular season.

Objective:

To prospectively study the incidence, types, and mechanisms of ice hockey injuries in an elite Japanese ice hockey team.

Design:

Prospective observational cohort study design.

Setting:

An elite ice hockey team, Tokyo, Japan.

Patients or Other Participants:

Ninety-four players during the 2002–2005 seasons.

Main Outcome Measure(s):

Data were collected for 3 consecutive seasons using an injury reporting form.

Results:

The overall game injury rate was 74.3 per 1000 player-game hours and 11.7 per 1000 player-game hours for injuries resulting in any time loss. The overall practice injury rates were 11.2 per 1000 player-practice hours and 1.1 per 1000 player-practice hours for injuries resulting in any time loss. Forwards had the highest rate of injury, followed by defensemen and then goalkeepers. Contusions were the most common injury, followed by strains, lacerations, and sprains.

Conclusions:

Most injuries among Japanese ice hockey players occurred during games. Game or play intensity may influence the injury rate during games.     

Neurocognitive performance of concussed athletes when symptom free

CONTEXT: Concussed athletes may underreport concussion-related symptoms in order to expedite return to play. Whether neurocognitive impairments persist once concussion-related symptoms resolve has yet to be determined. Reliance on athlete-reported, postconcussion symptoms when making return-to-play decisions may expose athletes to subsequent injury if complete recovery has not occurred. OBJECTIVE: To evaluate the presence of neurocognitive decrements in concussed athletes no longer reporting concussion-related symptoms. DESIGN: Within-groups design. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-one National Collegiate Athletic Association Division I collegiate athletes (16 men, 5 women). Age = 19.81 +/- 1.25 years, height = 180.95 +/- 10.62 cm, mass = 93.66 +/- 27.60 kg, and previous concussions = 1.76 +/- 2.02. MAIN OUTCOME MEASURE(S): The ImPACT concussion assessment test was administered to concussed athletes at baseline, when symptomatic (within 72 hours of injury), and when asymptomatic. Index scores of verbal memory, visual memory, visual-motor speed, reaction time, and concussion-related symptoms were recorded at each session. The Symptom Assessment Scale was administered daily after injury to establish when the athlete became asymptomatic. RESULTS: When assessed within 72 hours of concussion, 81% of the athletes showed deficits on at least 1 ImPACT variable. At the asymptomatic time point, 38% of the concussed athletes continued to demonstrate neurocognitive impairment on at least 1 ImPACT variable. CONCLUSIONS: Neurocognitive decrements may persist when athletes no longer report concussion-related symptoms. The exclusive use of symptom reports in making a return-to-play decision is not advised. A multifaceted approach to concussion assessment that includes evaluation of a myriad of functions is warranted.     

Individual Impact Magnitude vs. Cumulative Magnitude for Estimating Concussion Odds

Helmeted impact devices have allowed researchers to investigate the biomechanics of head impacts in vivo. While increased impact magnitude has been associated with greater concussion risk, a definitive concussive threshold has not been established. It is likely that concussion risk is not determined by a single impact itself, but a host of predisposing factors. These factors may include genetics, fatigue, and/or prior head impact exposure. The objective of the current paper is to investigate the association between cumulative head impact magnitude and concussion risk. It is hypothesized that increased cumulative magnitudes will be associated with greater concussion risk. This retrospective analysis included participants that were recruited from regional high-schools in Illinois and Michigan from 2007 to 2014 as part of an ongoing study on concussion biomechanics. Across seven seasons, 185 high school football athletes were instrumented with the Head Impact Telemetry system. Out of 185 athletes, 31 (17%) sustained a concussion, with two athletes sustaining two concussions over the study period, yielding 33 concussive events. The system recorded 78,204 impacts for all concussed players. Linear acceleration, rotational acceleration, and head impact telemetry severity profile (HITsp) magnitudes were summed within five timeframes: the day of injury, three days prior to injury, seven days prior to injury, 30 days prior to injury, and prior in-season exposure. Logistic regressions were modeled to explain concussive events based on the singular linear acceleration, rotational acceleration, and HITsp event along with the calculated summations over time. Linear acceleration, rotational acceleration, and HITsp all produced significant models estimating concussion (p < 0.05). The strongest estimators of a concussive impact were the linear acceleration (OR = 1.040, p < 0.05), rotational acceleration (OR = 1.001, p < 0.05), and HITsp (OR = 1.003, p < 0.05) for the singular impact rather than any of the cumulative magnitude calculations. Moreover, no cumulative count measure was significant for linear or rotational acceleration. Results from this investigation support the growing literature indicating cumulative magnitude is not related to concussion likelihood. Cumulative magnitude is a simplistic measure of the total exposure sustained by a player over a given period. However, this measure is limited as it assumes the brain is a static structure unable to undergo self-repair. Future research should consider how biological recovery between impacts may influence concussion risk.     

Public Attitudes and Knowledge About Youth Sports Participation and Concussion Risk in an Urban Area

Background

Every year, millions of children in the United States participate in youth full-contact sports, which carry concussion risks—the long-term sequelae of which are not well understood. We examined the attitudes and knowledge of adults in Chicago about youth sports participation, concussion risk, and whether physicians should counsel against youth participation in full-contact sports.

Is Neuropsychological Testing Useful in the Management of Sport-Related Concussion?

Objective: Neuropsychological (NP) testing has been used for several years as a way of detecting the effects of sport-related concussion in order to aid in return-to-play determinations. In addition to standard pencil-and-paper tests, computerized NP tests are being commercially marketed for this purpose to professional, collegiate, high school, and elementary school programs. However, a number of important questions regarding the clinical validity and utility of these tests remain unanswered, and these questions present serious challenges to the applicability of NP testing for the management of sport-related concussion. Our purpose is to outline the criteria that should be met in order to establish the utility of NP instruments as a tool in the management of sport-related concussion and to review the degree to which existing tests have met these criteria.Data Sources: A comprehensive literature review of MEDLINE and PsychLit from 1990 to 2004, including all prospective, controlled studies of NP testing in sport-related concussion.Data Synthesis: The effects of concussion on NP test performance are so subtle even during the acute phase of injury (1–3 days postinjury) that they often fail to reach statistical significance in group studies. Thus, this method may lack utility in individual decision making because of a lack of sensitivity. In addition, most of these tests fail to meet other psychometric criteria (eg, adequate reliability) necessary for this purpose. Finally, it is unclear that NP testing can detect impairment in players once concussion-related symptoms (eg, headache) have resolved. Because no current guideline for the management of sport-related concussion allows a symptomatic player to return to sport, the incremental utility of NP testing remains questionable.Conclusions/Recommendations: Despite the theoretic rationale for the use of NP testing in the management of sport-related concussion, no NP tests have met the necessary criteria to support a clinical application at this time. Additional research is necessary to establish the utility of these tests before they can be considered part of a routine standard of care, and concussion recovery should be monitored via the standard clinical examination and subjective symptom checklists until NP testing or other methods are proven effective for this purpose.     

Analysis of cerebral concussion frequency with the most commonly used models of football helmets

Data on helmet models used and occurrence of cerebral concussions over five seasons were collected from a representative sample of college football teams including a total of 8,312 player-seasons and 618,596 athlete-exposures to the possibility of being injured in a game or practice. Results showed that players with a history of concussion any time during the previous 5 years were six times as likely to suffer a new concussion as those with no previous history. In light of previous studies showing cognitive deficits for up to 30 days following even minor head injuries, and the growing awareness of “second impact” fatalities, these data support a need for reconsideration of the common practice of immediate return to play following non-loss-of-consciousness head injuries. Results on concussion frequency in ten models of football helmets indicated a significantly lower than expected frequency in the Riddell M155 and a significantly higher frequency in the Bike Air Power. All other models performed within expectations. This study demonstrates the need for monitoring on-the-field performance of football helmets through continuing epidemiological studies to supplement laboratory test data, which cannot duplicate all the factors involved in actual helmet performance.     

The assessment of airway maneuvers and interventions in university Canadian football, ice hockey, and soccer players

Context:

Managing an airway in an unconscious athlete is a lifesaving skill that may be made more difficult by the recent changes in protective equipment. Different airway maneuvers and techniques may be required to help ventilate an unconscious athlete who is wearing full protective equipment.

Objective:

To assess the effectiveness of different airway maneuvers with football, ice hockey, and soccer players wearing full protective equipment.

Design:

Crossover study.

Setting:

University sports medicine clinic.

Patients or Other Participants:

A total of 146 university varsity athletes, consisting of 62 football, 45 ice hockey, and 39 soccer players.

Intervention(s):

Athletes were assessed for different airway and physical characteristics. Three investigators then evaluated the effectiveness of different bag-valve-mask (BVM) ventilation techniques in supine athletes who were wearing protective equipment while inline cervical spine immobilization was maintained.

Main Outcome Measure(s):

The effectiveness of 1-person BVM ventilation (1-BVM), 2-person BVM ventilation (2-BVM), and inline immobilization and ventilation (IIV) was judged by each investigator for each athlete using a 4-point rating scale.

Results:

All forms of ventilation were least difficult in soccer players and most difficult in football players. When compared with 1-BVM, both 2-BVM and IIV were deemed more effective by all investigators for all athletes. Interference from the helmet and stabilizer were common reasons for difficult ventilation in football and ice hockey players.

Conclusions:

Sports medicine professionals should practice and be comfortable with different ventilation techniques for athletes wearing full equipment. The use of a new ventilation technique, termed inline immobilization and ventilation, may be beneficial, especially when the number of responders is limited.     

Brain Injury Prediction: Assessing the Combined Probability of Concussion Using Linear and Rotational Head Acceleration

Recent research has suggested possible long term effects due to repetitive concussions, highlighting the importance of developing methods to accurately quantify concussion risk. This study introduces a new injury metric, the combined probability of concussion, which computes the overall risk of concussion based on the peak linear and rotational accelerations experienced by the head during impact. The combined probability of concussion is unique in that it determines the likelihood of sustaining a concussion for a given impact, regardless of whether the injury would be reported or not. The risk curve was derived from data collected from instrumented football players (63,011 impacts including 37 concussions), which was adjusted to account for the underreporting of concussion. The predictive capability of this new metric is compared to that of single biomechanical parameters. The capabilities of these parameters to accurately predict concussion incidence were evaluated using two separate datasets: the Head Impact Telemetry System (HITS) data and National Football League (NFL) data collected from impact reconstructions using dummies (58 impacts including 25 concussions). Receiver operating characteristic curves were generated, and all parameters were significantly better at predicting injury than random guessing. The combined probability of concussion had the greatest area under the curve for all datasets. In the HITS dataset, the combined probability of concussion and linear acceleration were significantly better predictors of concussion than rotational acceleration alone, but not different from each other. In the NFL dataset, there were no significant differences between parameters. The combined probability of concussion is a valuable method to assess concussion risk in a laboratory setting for evaluating product safety.     

Head Impact Biomechanics in Youth Hockey: Comparisons Across Playing Position, Event Types, and Impact Locations

The age at which young hockey players should safely body check is unknown. We sought to determine if playing position (defensemen vs. forwards), event type (practice vs. game), or head impact location (top vs. back vs. front vs. sides) had an effect on head impact biomechanics in youth hockey. A total of 52 Bantam (13–14 years old) and Midget (15–16 years old) ice hockey players wore accelerometer-instrumented helmets for two seasons. Biomechanical data were captured for 12,253 head impacts during 151 games and 137 practices. Random intercepts general mixed linear models were employed to analyze differences in linear acceleration, rotational acceleration, and HITsp by player position, event type, and head impact location. Head impacts sustained during games resulted in greater rotational acceleration and HITsp than those sustained during practices. No event type or playing position differences in linear acceleration were observed. Impacts to the top of the head resulted in greater linear acceleration, but lower rotational acceleration and HITsp, than impacts to back, front, or side of the head. Side head impacts yielded greater rotational acceleration and HITsp compared to the other head impact locations. Since linear and rotational accelerations were observed in all impacts, future hockey helmet design standards should include rotational acceleration limits in addition to the current linear acceleration standards.