A systematic video analysis of National Hockey League (NHL) concussions, part I: who, when, where and what?

Injury rate and characteristics in Japanese male professional ice hockey players: prospective study of 60 players over 10 seasons

Objectives

We aimed to assess the injury rate and characteristics in Japanese male professional ice hockey players.

Methods

This study involved an inclusive cohort of male ice hockey players from a Japanese professional team competing in the 2010-2011 through the 2019-2020 seasons. An injury was defined as the 'time-loss and medical attention' definition of the International Ice Hockey Federation. All injuries that occurred during games and practice sessions were recorded daily on injury charts by the team athletic trainers and/or physician. Game-related injury rates were analysed using both the athlete-at-risk (AAR) and time on ice (TOI) methods.

Results

Sixty players were included in the study. A total of 479 injuries were recorded, with 307 (64%) occurring during 451 games and 172 (36%) occurring during the practice sessions. The game-related injury rates obtained using the AAR and TOI methods were not statistically different (p>0.05): 115.3 (95% CI 107.1 to 123.1) and 116.8 (95% CI 109.9 to 124.7) per 1000 player-game hours, respectively. Most injuries involved the upper extremities (39.9% game-related, 32.6% practice-related), followed by the lower extremities (23.5% game-related, 32.5% practice-related). The most frequent mechanism of game-related injury was body checking (45.4%).

Conclusion

We observed a higher injury rate in a Japanese male professional team compared with rates reported in other leagues. The reported injury characteristics should help to improve injury prevention strategies that should target shoulder dislocations caused by body checking, and finger or wrist fractures resulting from contact with a hockey stick or puck impact.

Quantifying the effects of ice hockey upper body pads on mobility and comfort

Ice hockey is a high-intensity sport in which pads such as shoulder and elbow pads (S/EPs) are necessary to help players avoid injury. However, they can also affect mobility and comfort, thereby affecting players' on-ice performance. We aimed to quantify the effects of S/EPs on mobility and comfort by comparing the range of motion (ROM) of nine elite college-level ice hockey players performing static (nine single-DOF upper-body movements) and dynamic (wrist and slap shots) tasks under six pad conditions (no S/EPs and five types of S/EPs). We also analyzed the relationship between ROM and subjective comfort to provide an objective comfort evaluation of hockey pads. Five types of S/EPs restrict ROM at different levels, imposing additional mobility restrictions. We found significant differences among the five types and a high correlation between comfort and ROM. We conducted a comprehensive evaluation of the impact of ice hockey pads on mobility and comfort.

Concussion Characteristics in the National Hockey League Before and After the Introduction of Rule 48

Importance

A rule prohibiting a direct hit to the lateral side of the head (ie, Rule 48-Illegal Check to the Head) was introduced in the National Hockey League (NHL) in the 2010-2011 season and refined in the 2011-2012 season to widen the application to include direct contact to all areas of the head.

Objective

To compare the incidence and proportion of concussions that occurred following hits to the head before and after the implementation of Rule 48.

Design, Setting, and Participants

This retrospective cohort study used a before and after design to evaluate concussions among NHL players in regular season games. Data from the 4 seasons preceding the implementation of Rule 48 (2006-2007 to 2009-2010) were compared with data from 5 seasons following its implementation (2014-2015 to 2018-2019). Data were analyzed from October 31, 2021, to November 30, 2022.

Main Outcomes and Measures

The incidence and relative proportion of concussion characteristics and mechanisms before and after the introduction of Rule 48.

Results

In the analysis of 688 concussions for NHL seasons spanning 2006 to 2010 (n = 231) and 2014 to 2019 (n = 457), there was an overall increase in the incidence of concussion between the 2 time frames, although the incidence of concussions due to hits to the lateral aspect of the head decreased from 1.6/100 games to 1.0/100 games (estimated difference, 0.6/100 games [90% credible interval (CrI), 0.30/100 games to 0.90/100 games). There was also a reduction of 18.8 (90% CrI, 13.0-23.7) percentage points in the proportion of concussions due to hits to the lateral aspect of the head from 80 of 231 concussions (34.6%) to 61 of 457 concussions (13.3%). The incidence of concussions following hits to the head from body checks using the shoulder, arm, and glove was similar before and following the implementation of Rule 48. However, the proportion was reduced 14.7 percentage points from 113 of 231 concussions (48.9%) before to 149 of 457 concussions (32.6%) after implementation of Rule 48 (90% CrI of the difference, 8.9-20.7 percentage points).

Conclusions and Relevance

The findings of this cohort study of NHL players suggest that after the introduction of Rule 48, the incidence rate and proportion of concussions from contact to the lateral aspect of the head decreased, as did the proportion of concussions following direct hits to the head.

Associations between the circumstances and severity of head impacts in men's university ice hockey

Improved evidence on the most common and severe types of head impacts in ice hockey can guide efforts to preserve brain health through improvements in protective gear, rink design, player training, and rules of play. In this observational cohort study of men's university hockey, we compared video evidence on the circumstances of 234 head impacts to measures of head impact severity (peak linear accelerations and rotational velocities) from helmet-mounted sensors (GForceTracker). Videos were analyzed with a validated questionnaire, and paired with helmet sensor data. Shoulder-to-head impacts were more common than hand- or elbow-, but there were no differences in head impact severity between upper limb contact sites (p ≥ 0.2). Head-to-glass impacts were nearly four times more common, and just as severe as head-to-board impacts (p ≥ 0.4). Head impacts resulting in major penalties (versus no penalty), or visible signs of concussion (versus no signs), involved greater head rotational velocities (p = 0.038 and 0.049, respectively). Head impacts occurred most often to the side of the head, along the boards to players in their offensive zone without puck possession. Head impact severity did not differ between cases where the head was (versus was not) the primary site of contact (p ≥ 0.6). Furthermore, penalties were called in only 4% of cases where the head was the initial point of contact. Accordingly, rules that focus on primary targeting of the head, while important and in need of improved enforcement, offer a limited solution.

Fighting in professional ice hockey: it's time for a change

Ice hockey has long been defined by a level of violence not seen in other sports. The rough-and-tough vigilante nature of the game was often employed as a method of enticing fans. Play in the National Hockey League (NHL) evolved throughout the 20th century as the rules governing it did. The nuances of what was allowed on the ice was slowly defined, but the league always fell short of an outright ban on fighting. Notably, the NHL allows fighting while international and Olympic leagues do not. Proponents of fighting's continued presence in the NHL argue that it can attract fans, facilitate momentum changes, help win games, and allows for social regulation on the ice. However, analyses of these theories have found little definitive evidence, calling the utility of fighting into question. The economics of fighting in hockey reveal high salary payouts, increased cost of injury, and a lack of correlation with ticket sales. Additionally, there is a concern for concussions sustained during fighting which has the potential for long term, detrimental mental health effects for athletes. In this analysis, we explore the history and evolution of fighting in the NHL, as well as the reasons behind its continued presence in the game, the risks associated with fighting, and the economics behind it all. Based upon these bodies of evidence, we make a proposal regarding the future of fighting in the NHL.

How to harness and improve on video analysis for youth rugby player safety: a narrative review

Video analysis is a useful tool for injury surveillance in rugby union. There are few video analysis studies in the professional female game, with most studies published in the male elite/professional settings. Moreover, there is a sparsity of literature in youth rugby settings. The following narrative review outlines the strengths and limitations of the current video analysis literature for injury surveillance in youth rugby union, highlights the importance of video analysis for youth rugby player safety and welfare, and discusses recommendations for using video analysis to inform player safety in youth rugby.

Head Impact in Blind Football During the Tokyo Paralympics: Video-Based Observational Study

ABSTRACT

Head impacts during blind football are common and have high injury rates; however, their characteristics and impact are still underreported. We compared head impact characteristics in blind football players with and without falls on all 18 official blind football match videos from the Tokyo 2020 Paralympic games. The rate of head impacts with falls was significantly higher in the preliminary phase, offense phase, and during dribbling. Significant differences in the region of the head impacted were also observed among the impact subjects/objects. The findings in this study would contribute to the development of injury prevention measures to minimize head injuries from head impact in blind football.

Fighting to the death: Does hockey fighting in the NHL affect players' longevity?

Hockey is a sport known for its violent nature. Specifically, hockey fights have consistently been an integral part of the National Hockey League. Past research has demonstrated that players are likely to be involved in fighting as a mechanism to gain fan support, generate game momentum or enhance team camaraderie. However, fighting naturally has negative health ramifications. In the current study, we sought to investigate if players' involvement in hockey fights throughout their career was associated with shorter life spans. Previous mortality studies have not distinguished hockey fighting from other aggressive aspects of this sport (e.g., in game physical contact with other players). We conducted an archival study examining the frequency of hockey fighting during the 1957-1971 NHL seasons and player longevity. A Kaplan-Meier survival analysis log-rank method and a subsequent Cox regression accounting for correlates showed no relationship between an elevated number of fights and a reduced lifespan. The lack of effect may indeed demonstrate a negligible influence on long-term health consequences in the context of a generally very physical game. However, with the relatively moderate levels of fighting in the period studied we recommend that the association be explored also in a subsequent era when NHL fighting peaked.

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.

A case-control study of tackle based head impact event (HIE) risk factors from the first three seasons of the National Rugby League Women's competition

Objective

The tackle is the most injurious event in rugby league and carries the greatest risk of concussion. This study aims to replicate previous research conducted in professional men's rugby league by examining the association between selected tackle characteristics and head impact events (HIEs) in women's professional rugby league.

Methods

We reviewed and coded 83 tackles resulting in an HIE and every tackle (6,318 tackles) that did not result in an HIE for three seasons (2018-2020) of the National Rugby League Women's (NRLW) competition. Tackle height, body position of the tackler and ball carrier, as well as the location of head contact with the other player's body were evaluated. Propensity of each situation that caused an HIE was calculated as HIEs per 1,000 tackles.

Results

The propensity for tacklers to sustain an HIE was 6.60 per 1,000 tackles (95% CI: 4.87-8.92), similar to that of the ball carrier (6.13 per 1,000 tackles, 95% CI: 4.48-8.38). The greatest risk of an HIE to either the tackler or ball carrier occurred when head proximity was above the sternum (21.66 per 1,000 tackles, 95% CI: 16.55-28.35). HIEs were most common following impacts between two heads (287.23 HIEs per 1,000 tackles, 95% CI: 196.98-418.84). The lowest propensity for both tackler (2.65 per 1,000 tackles, 95% CI: 0.85-8.20) and ball carrier HIEs (1.77 per 1,000 tackles, 95% CI: 0.44-7.06) occurred when the head was in proximity to the opponent's shoulder and arm. No body position (upright, bent or unbalanced/off feet) was associated with an increased propensity of HIE to either tackler or ball carrier.

Conclusions

In the NRLW competition, tacklers and ball carriers have a similar risk of sustaining an HIE during a tackle, differing from men's NRL players, where tacklers have a higher risk of HIEs. Further studies involving larger samples need to validate these findings. However, our results indicate that injury prevention initiatives in women's rugby league should focus on how the ball carrier engages in contact during the tackle as well as how the tackler executes the tackle.

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.

Fighting and Penalty Minutes Associated With Long-term Mortality Among National Hockey League Players, 1967 to 2022

Importance

National Hockey League (NHL) players are exposed to frequent head trauma. The long-term consequences of repetitive brain injury, especially for players who frequently engage in fighting, remains unknown.

Objective

To investigate the mortality rates and causes of death among NHL enforcers with more career fights and penalty minutes as compared with matched controls.

Design, Setting, and Participants

This matched cohort study examined 6039 NHL players who participated in at least 1 game in the seasons between October 11, 1967, and April 29, 2022, using official NHL data. Cohorts designated as enforcer-fighter (E-F) and enforcer-penalties (E-P) were selected. The E-F cohort consisted of players who participated in 50 or more career fights (n = 331). The E-P cohort included players with 3 or more penalty minutes per game (n = 183). Control-matched NHL players were identified for each E-F player (control-fighter [C-F]) (n = 331) and each E-P player (control-penalties [C-P]) (n = 183).

Exposures

Fighting and penalty minutes were both used as proxies for head trauma exposure. Players with significantly increased exposure to fighting and penalties (E-F and E-P cohorts) were compared with NHL players with less frequent exposure to head trauma (C-F and C-P cohorts).

Main Outcomes and Measures

Mortality rates and age at death of the enforcer and control cohorts, and their causes of death using data obtained from publicly available sources such as online and national news sources, including NHL.com.

Results

Among the 6039 NHL players identified (mean [SD] age, 47.1 [15.2] years), the mean (SD) number of fights was 9.7 (24.5). The mortality rates of E-F and C-F players (13 [3.9%] vs 14 [4.2%], respectively; P = .84) or E-P and C-P players (13 [7.1.%] vs 10 [5.5%]; P = .34) were not significantly different. The mean (SD) age at death was 10 years younger for E-F players (47.5 [13.8] years) and E-P players (45.2 [10.5] years) compared with C-F players (57.5 [7.1] years) and C-P players (55.2 [8.4] years). There was a difference in causes of death between the control and enforcer players (2 neurodegenerative disorders, 2 drug overdoses, 3 suicides, and 4 vehicular crashes among enforcers vs 1 motor vehicle crash among controls; P = .03), with enforcers dying at higher rates of overdose (2 of 21 [9.5%] vs 0 of 24) and suicide (3 of 21 [14.3%] vs 0 of 24) (P = .02).

Conclusions and Relevance

The findings of this matched cohort study indicate that there is no difference in overall mortality rates between NHL enforcers and controls. However, being an enforcer was associated with dying approximately 10 years earlier and more frequently of suicide and drug overdose.

Video analysis of Achilles tendon ruptures in professional male football (soccer) reveals underlying injury patterns and provides strategies for injury prevention

PURPOSE

In professional football (soccer), Achilles tendon ruptures are severe injuries. Video analysis promotes a better understanding of the underlying situational and biomechanical patterns, and provides a roadmap for future research to improve the management and prevention of Achilles tendon ruptures. The purpose of this study was to identify injury patterns contributing to acute Achilles tendon ruptures in professional male football players.

METHODS

Professional male football players with an acute Achilles tendon rupture were identified using an online database. For every in-competition injury, the corresponding football match was detected. Video footage of the injury was accessed using Wyscout.com or publicly available video databases. Situational patterns and injury biomechanics of the injury frame were independently analysed by two reviewers using a standardised checklist and a motion analysis software. Finally, consensus was reached to describe the main injury patterns of Achilles tendon ruptures in professional male football players.

RESULTS

The search identified video footage of 80 Achilles tendon ruptures in 78 players. Most injuries (94%) occurred through indirect or non-contact mechanisms. The kinematic analysis revealed characteristic joint positions at the time of injury consisting of hip extension, knee extension, ankle dorsiflexion, foot abduction, and foot pronation in most cases. The underlying direction of movement was from flexion to extension (knee) and from plantarflexion to dorsiflexion (ankle). Player actions identified as main injury patterns were stepping back (26%), landing (20%), running/sprinting (18%), jumping (13%), and starting (10%).

CONCLUSION

Most Achilles tendon ruptures in professional male football players are closed-chain indirect or non-contact injuries. Sudden loading to the plantarflexor musculotendinous unit remains to be the main component for most cases. By achieving a better understanding of underlying injury mechanisms, this study provides new strategies for the prevention of Achilles tendon ruptures.

LEVEL OF EVIDENCE

Level IV.

Soft-shell headgear in rugby union: a systematic review of published studies

Objectives

To review the rate of soft-shell headgear use in rugby union, consumer knowledge of the protection potential of soft-shell headgear, incidence of concussion reported in rugby headgear studies, and the capacity of soft-shell headgear to reduce acceleration impact forces.

Design

A systematic search was conducted in July and August 2021 using the databases SPORT Discus, PubMed, MEDLINE, CINAHL (EBSCO), Scopus, and Science Direct. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The protocol for this systematic review was registered on PROSPERO (registration number: CRD42021239595).

Outcome measures

Rates of headgear use, reports of estimated protection of headgear against head injury, incidence of concussion and magnitude of impact collisions with vs. without headgear, impact attenuation of headgear in lab studies.

Results

Eighteen studies were identified as eligible: qualitative (N = 4), field (N = 7), and lab (N = 7). Qualitative studies showed low rates of headgear use and varying understanding of the protection afforded by headgear. Field studies showed negligible association of headgear use with reduced impact magnitude in headgear vs. non-headgear cohorts. Lab studies showed increased energy attenuation for thicker headgear material, poorer performance of headgear after repetitive impacts and increased drop heights, and promising recent results with headgear composed of viscoelastic polymers.

Conclusions

Rates of adoption of soft-shell headgear remain low in rugby and any association between its use and reduction in acceleration impact forces remains unclear. Lab results indicating improved impact attenuation need to be validated in the field. Further headgear-related research is needed with youth and female rugby players.

[Traumatic brain injuries in winter sports : An overview based on the winter sports skiing, snowboarding and ice hockey]

In winter sports, skiers, snowboarders and ice hockey players have the highest risk of traumatic brain injuries (TBI). In skiing/snowboarding severe TBIs are of concern; in ice hockey, repetitive minor TBIs are frequent. The main causes of TBI in recreational skiing are collisions with trees; in professionals falls due to technical or tactical mistakes are the main causes. In ice hockey 10-15% of all injuries are due to a sports-related concussion (SRC), mostly caused by player-opponent contact. The pathomechanism in TBI is a combination of rotational and linear acceleration during head impact, which causes a diffuse axonal injury. Long-term complications such as neurodegenerative diseases and functional deficits are of relevance. Prevention by wearing helmets is effective, but less effective in TBI/SRC than in focal injuries.

Analysis of wheelchair falls in team sports at the Paralympic Games: video-based descriptive comparison between the Rio 2016 and Tokyo 2020 games

OBJECTIVES

To identify the fall characteristics of athletes in wheelchair rugby and wheelchair basketball during the Tokyo 2020 Paralympic Games and descriptively compare these with those of the Rio 2016 Paralympic Games.

DESIGN

Cross-sectional analysis.

PRIMARY AND SECONDARY OUTCOME MEASURES

We obtained video footage from the International Paralympic Committee of the Tokyo 2020 Paralympic Games that included 8 teams from each of the 18 wheelchair rugby and 10 wheelchair basketball games (men and women). The data were analysed to evaluate the number of falls, class difference (low or high pointer), time of play during the fall, phase of play, contact with other athletes, fall direction, fall location and the body part that first contacted the floor during the fall. These data from the Rio 2016 and Tokyo 2020 games were compared.

RESULTS

Overall, 430 falls (rugby, 104; men's basketball, 230 and women's basketball, 96) occurred (average per game ±SD: 5.8±3.1, 23.0±5.4 and 9.6±5.0, respectively). Significant differences in class, direction, fall location and body part point of contact between the three sports were observed. In wheelchair rugby, falls occurred mainly in high pointers and tended to be more lateral due to contact. In wheelchair basketball, falls occurred more in female high-pointers and in male low pointers, with more forward falls due to forward contact. Unlike in the Rio 2016 games, no difference between the events based on the presence or absence of contact was observed in the Tokyo 2020 games.

CONCLUSIONS

The number of falls increased in Tokyo 2020 compared with Rio 2016, with no significant difference in the characteristics of falls between the Rio 2016 and Tokyo 2020 games. Only in men's wheelchair basketball, the number of falls in low pointers significantly increased in the Tokyo 2020 games when compared with that in the Rio 2016 games.

Mechanisms of Sports Concussion in Taekwondo: A Systematic Video Analysis of Seven Cases

Sports-related traumatic brain injuries are the most common injury in adolescents and young adults due to recurrent concussion experiences and head shock. Therefore, this study was designed to describe player characteristics and situational factors associated with concussions in the World Taekwondo Championships using systematic video analysis. Athlete injury data were collected using a web-based injury surveillance system at the World Taekwondo Championships organized by World Taekwondo from 2017 to 2019. Seven video footage were independently analyzed by four analysts using a modified Heads-Up Checklist. Descriptive statistical analysis was used. The incidence of concussion was 3.21 per 1000 games. Most players with concussions were shorter than their opponents, and most concussions were caused by a roundhouse kick on the front of the face. Regarding the acceleration direction of the head after the impact, transverse and multiplane directions were the most common. Most players with a concussion have used a closed stance and did not use blocking techniques during the defense. The rate of concussions caused by penalties was 42.9%. Based on our findings, no other injury mechanisms, except for direct blows to the head, were observed. Therefore, education on the risk and symptoms of concussion, the appropriate management and blocking techniques should be emphasized in TKD-S to reduce incidence of concussion.

Risk Factors Based on Analysis of Injury Mechanism and Protective Equipment for Ice Hockey Amateur Players

Considering the increasing popularity of ice hockey in South Korea, types of injuries and protective equipment for amateur club members need to be further studied. The purpose of the study is to investigate various injuries and protective equipment used by amateur players and to analyze different risk factors by collecting information on areas of injury and their mechanisms. The online survey for 102 participants was designed to address the general information of participants, types of injuries, information about ice hockey equipment, and open-ended questions about injuries and equipment. We conducted in-depth face-to-face interviews with five players about their experiences with injury and opinions about the protective equipment. In total, 60% of the survey participants had experienced injuries, including to the knee (22.6%), shoulder (21.6%), ankle (20.6%), and wrist (14.7%), in order of frequency. Types of injury included sprain (33.3%), contusion (31.4%), fracture (17.7%), abrasion (10.8%), and concussion (0.9%). Injury mechanisms included instances in which those with less proficiency in skating would be injured initially from player-to-player contact, and from landing on the ice or crashing into the fence afterward. We acknowledged how important wearing correctly sized equipment is for protection, and we highlighted the need to develop protective gear that accommodates Asian body measurements.

The Impact of the Instigator Rule on Fighting in the National Hockey League

Background

Fighting is often considered an essential part of professional hockey. Increased ticket sales, a means to self-regulate other dangerous gameplay, and helping teams win are a few of the reasons that fighting advocates provide for retaining fighting in the NHL. However, fighting trends have changed over the past 50 years. Given the recent data on concussions and player safety, an in-depth analysis of fighting is required to understand if fighting has a place in the future of the NHL.

Methods

Seasonal statistical team data on NHL teams from the 1967 to 2019 seasons were collected and analyzed using publicly available databases. Specific outcome variables of interest related to fighting, penalties, the final team record for a given season, and final standing were recorded. The data were divided into subgroups according to "era of play" and before/after the implementation of the instigator rule. The trends in fighting, seasonal outcomes, and other minor penalties were assessed to determine the trends in fighting over the past 50 years, the relationship between fighting and winning, and the impact of the instigator rule.

Results

Fights per game decreased significantly after the implementation of the instigator rule (0.71 to 0.51 fights per game, p < 0.0001). There was no significant difference in fights per game when comparing Stanley Cup champions to nonplayoff teams in either the modern era (0.36 vs. 0.42, p = 0.43) or the expansion era (0.45 vs. 0.51, p = 0.49). Only two Stanley Cup champions (the Flyers 1974-1975 and the Ducks 2006-2007) led the league in fighting. A multivariate regression analysis comparing fights per game and points earned per season divided by the number of games played revealed a statistically significant inverse relationship (coefficient = -0.16, p < 0.001).

Conclusion

Our analysis demonstrates that the Instigator rule achieved its intended effect to decrease the number of fights per game. In the current era of professional hockey, there is no compelling evidence that a team with more fights per game will achieve greater seasonal success. These results continue to cast doubt on the belief that fighting is a necessary strategy for winning games at the NHL level.

Video Analysis of Acute Injuries in Elite Field Hockey

OBJECTIVE

With this study, we aim to determine the value of video assessment of acute injuries in field hockey.

DESIGN

Retrospective video analysis for acute injuries.

SETTING

Professional field hockey.

PARTICIPANTS

Seven women and men's field hockey tournaments (World League, Champions Trophy) in 2015.

INTERVENTIONS

Not applicable.

OUTCOME MEASURES

An injury was defined as any new musculoskeletal complaint leading to time stoppage and medical attention. The outcome measures were time at play, location on the pitch, type of injury, injured body part, and injury mechanism.

RESULTS

A total of 190 injuries occurred in 179 matches (55/73 female and 135/106 male matches). There were 0.75 injuries per match for women [confidence interval (CI, 0.31-1.13)] and 1.27 injuries per match for men (CI, 0.88-1.61). The number of injuries per 1000 player match hours was 34.20 for women (CI, 14.04-51.29) and 57.89 for men (CI, 29.78-73.12). The highest injury frequency occurred within the third quarter and within the circle. Contusion was the most common injury type (90.9% in women and 96.3% in men). The leading causes of injuries were hits by the ball or stick and collisions with another player. The head/face was the most affected body part in both sex groups (32.7% in women and 29.6% in men).

CONCLUSIONS

Video analysis revealed data on injury incidence within the same range of previous reports in elite field hockey. Its advantages, such as slow motion and repetitive play of injury scenes, could contribute valuable information if incorporated into the injury recording process.

Effective stiffness, damping and mass of the body during laboratory simulations of shoulder checks in ice hockey

Ice hockey is a fast-paced sport with a high incidence of collisions between players. Shoulder checks are especially common, accounting for a large portion of injuries including concussions. The forces generated during these collisions depend on the inertial and viscoelastic characteristics of the impacting bodies. Furthermore, the effect of shoulder pads in reducing peak force depends on the baseline (unpadded) properties of the shoulder. We conducted experiments with nine men's ice hockey players (aged 19-26) to measure their effective shoulder stiffness, damping and mass during the impact stage of a shoulder check. Participants delivered a style of check commonly observed in men's university ice hockey, involving lateral impact to the deltoid region, with the shoulder brought stationary by the collision. The effective stiffness and damping coefficient of the shoulder averaged 12.8 kN/m and 377 N-s/m at 550 N, and the effective mass averaged 47% of total body mass. The damping coefficient and stiffness increased with increasing force, but there was no significant difference in the damping coefficient above 350 N. Our results provide new evidence on the dynamics of shoulder checks in ice hockey, as a starting point for designing test systems for evaluating and improving the protective value of shoulder pads.

Aging Affects Lower Limb Joint Moments and Muscle Responses to a Split-Belt Treadmill Perturbation

Age-related changes cause more fall-related injuries and impede the recoveries by older adults compared to younger adults. This study assessed the lower limb joint moments and muscle responses to split-belt treadmill perturbations in two groups (14 healthy young group [23.36 ± 2.90 years] and 14 healthy older group [70.93 ± 4.36 years]) who performed two trials of unexpected split-belt treadmill perturbations while walking on a programmable split-belt treadmill. A motion capture system quantified the lower limb joint moments, and a wireless electromyography system recorded the lower limb muscle responses. The compensatory limb's (i.e., the tripped limb's contralateral side) joint moments and muscle responses were computed during the pre-perturbation period (the five gait cycles before the onset of a split-belt treadmill perturbation) and the recovery period (from the split-belt treadmill perturbation to the baseline gait relying on the ground reaction forces' profile). Joint moments were assessed by maximum joint moments, and muscle responses were quantified by the normalization (%) and co-contraction index (CCI). Joint moments and muscle responses of the compensatory limb during the recovery period were significantly higher for the YG than the OG, and joint moments (e.g., knee flexion and extension and hip flexion moments) and muscle responses during the recovery period were higher compared to the pre-perturbation period for both groups. For CCI, the older group showed significantly higher co-contraction for biceps femoris/rectus femoris muscles than the young group during the recovery period. For both groups, co-contraction for biceps femoris/rectus femoris muscles was higher during the pre-perturbation period than the recovery period. The study confirmed that older adults compensated for muscle weakness by using lower joint moments and muscle activations and increasing muscle co-contractions to recover balance after split-belt treadmill perturbations. A better understanding of the recovery mechanisms of older adults who train on fall-inducing systems could improve therapeutic regimens.

Reliability of Using the Proposed International Consensus Video Signs of Potential Concussion for National Rugby League Head Impact Events

BACKGROUND

Consensus on the definition of extant video signs of concussion have recently been proposed by representatives of international sporting codes for global consistency across professional leagues.

OBJECTIVE

To review the reliability of the proposed international consensus video signs of concussion in National Rugby League (NRL) head impact events (HIEs).

METHODS

The video signs of concussion were coded for every HIE during the 2019 NRL season. Coding was conducted blinded to the concussion status. Frequency, sensitivity, specificity, and a receiver operating characteristic curve were calculated.

RESULTS

There were 943 HIEs identified over the 2019 NRL season, of which 106 resulted in a diagnosed concussion. The most frequently observed video sign in concussed athletes was blank/vacant look (54%), which was also the most sensitive video sign (0.54, CI: 0.44-0.63), while the most specific was tonic posturing (0.99, CI: 0.99-1.00). In 43.4% of diagnosed concussions none of the 6 video signs were present. The 6 video signs demonstrated a "fair" ability to discriminate between concussion and nonconcussion HIEs (area under the curve = 0.76).

CONCLUSION

International consensus agreement between collision sports for extant video signs of concussion and the definition of those extant video signs are clinically important. The selection of signs requires rigorous assessment to examine their predictive value across all sports and within individual sports, and to determine further video signs to compliment and improve the identification of possible concussion events within various sports. The current study demonstrated that, for NRL-related HIEs, the diagnostic accuracy of video signs varies.

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.

Performance After Concussion in National Hockey League Players

CONTEXT

Concussions 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.

OBJECTIVE

To 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.

DESIGN

Cross-sectional study.

SETTING

The NHL Injury Viz and sports reporting websites.

PATIENTS OR OTHER PARTICIPANTS

Players 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.

RESULTS

When 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.

CONCLUSIONS

After concussion, NHL player performance did not change.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Frequency of overtime and consecutive games and their impact on injury rate in the National Hockey League (NHL)

OBJECTIVES

Ice hockey is a high-intensity contact sport that places athletes at an elevated risk for injury relative to other sports. The purpose of the current study was to analyze factors contributing to fatigue and decreased recovery time and their associations with injury incidence among professional athletes in the National Hockey League (NHL).

METHODS

A retrospective review of all injuries suffered by NHL athletes during six consecutive seasons from 2013 to 2019 was performed. Team schedules were analyzed to assess (1) the number of instances with games on consecutive calendar days, (2) the number of overtime games, and (3) the number of overtime games within three calendar days of a previous overtime game. A Spearman's rank correlation coefficient was calculated from this data to assess the association between these factors and injury rates.

RESULTS

In total, 4886 injuries were suffered by NHL players during the period of study, with the 2013-2014 regular season highest injury rate per 1000 athletic exposures (15.8). The lower body was the most frequently injured body area (25.0% of all injuries), followed by injuries to the upper body (23.7%). In an analysis of the number of overtime games and games on consecutive days and their relationships to injury rate, only overtime games within three calendar days and total injuries were found to have a significant association (ρ = 0.19, p = 0.01).

CONCLUSION

The weak positive correlation between the number of overtime games within threedays of a previous overtime game and total injuries in professional ice hockey players suggests that overtime games played within a short period of time place athletes at increased risk for injury. Further studies are necessary to address this on an athlete-by-athlete level.

Exposure to brain trauma in six age divisions of minor ice hockey

Acute and chronic neurological risks associated with brain trauma sustained in professional ice hockey has generated concern for youth participants. Minor hockey is a different game when compared to elite players presenting distinctive risk factors for each age division. Objective measures of brain trauma exposure were documented for six divisions in minor ice hockey; U7, U9, U11, U13, U15, U18. Game video analysis, physical reconstruction and computational modelling was employed to capture the event conditions, frequency of impacts, frequency of high strain magnitude (>0.17) impacts, and cumulative trauma. The results showed proportional differences in the event conditions; event type, closing velocity, and head impact location, informing the improvement of age appropriate protection, testing protocols, and safety standards. Frequency of events were highest for U7 when players were learning to skate, and again in U18 as game physicality increases. No significant difference was observed in frequency of high magnitude impacts across age divisions. A peak in high magnitude impacts was empirically observed at both U7 and U15 where skill development in skating and body checking, respectively, were most prominent. Finally, a cumulative trauma metric incorporating frequency and magnitude of impacts provided a detailed analysis of trauma exposure provides for a targeted approach to managing injury risk specific to age division. Objective measures of brain trauma exposure identified in the current study are important to inform strategy, guide legislation and initiate policy for safe play in minor ice hockey.

Epidemiology of Traumatic and Overuse Injuries in Swiss Professional Male Ice Hockey Players

Background:

Ice hockey injury patterns in Europe were last evaluated in the 1990s.

Purpose:

The aim of this study was to assess the frequency, type, location, and incidence of traumatic injuries, as well as the prevalence and relative effect of overuse injuries in professional male ice hockey players.

Study Design:

Descriptive epidemiology study.

Methods:

Traumatic injuries were assessed using a standardized injury report form over a 1-year period (including the preparatory phase and season). The Oslo Sports Trauma Research Centre Overuse Injury Questionnaire was used to determine overall and substantial overuse injuries and their relative effect on ice hockey players.

Results:

Five Swiss National League teams participated in the study. From a total of 321 recorded injuries, 179 led to time loss from sport. The game-related time-loss injury incidence during the season was 88.6/1000 player-game hours.Time-loss injuries affected mainly the hip/groin/thigh region (23%), followed by the head (17%). Most time-loss injuries were classified as muscle strains (24%), followed by concussions (18%). The most common injury mechanism involved collision with an opponent’s body (31%), and right forward players (23%) were most likely to report a game-related injury. Most injuries (27%) occurred within the defending zone along the boards. The average prevalence rates of all overuse and substantial overuse injuries were 49% and 13%, respectively. The hip/groin displayed the highest average prevalence for all overuse problems (16%), translating to the highest relative effect.

Conclusion:

Muscle strains and concussions were the most frequent time-loss injuries in Swiss professional ice hockey players. The hip/groin was the most affected region for both traumatic and overuse injuries.

Concussions in the National Football League: the evolution of video review for assessing the frequency and reliability of visible signs

Background: The use of video review to document visible signs (VS) of sport-related concussion in the National Football League (NFL) is a novel method to recognize head injuries. Hypothesis/Purpose: The current pilot studies used varying methodologies to (1) examine the frequency of VS in concussed NFL players using the Australian Football League's (AFL) checklist, and (2) assess the reliability of VS between non-expert and expert raters. Study design: Cohort study Methods: In the first pilot study, two non-expert raters rated VS of SRC occurring in the 2015 NFL season (n = 96) using a single VS from the AFL checklist. Based on this pilot study, two expert raters then rated VS of SRC during the 2017 NFL season (n = 211) using all VS from the AFL checklist. The frequency, total percent agreement (TPA), and reliability (kappa coefficients) were calculated for all VS of concussion for the two seasons. Kappa agreement was classified as fair (.41-.60), moderate (.61-.80), or substantial (.81-1.00). Significance was set at p < .05. Results: The most frequent VS of concussion identified by both non-expert and expert raters were no behavior observed, slow to get up, and motor incoordination. The least frequent VS were impact seizure, blank/vacant look, and facial injury. For non-expert raters, the average TPA for VS ranged from 84% to 100% and kappa coefficients ranged from .52 to .68. For expert raters, the average TPA ranged from 83% to 100%, and kappa coefficients ranged from .56 to .86. Conclusion: In these preliminary analyses, use of multiple VS was a superior methodology, and the reliability of VS rating was stronger for experts. Due to the inherent differences in gameplay and protective equipment used in the NFL compared to other professional sports, it is our hope these data can generate new ways to improve existing practices and identify potentially novel VS of SRC.

Situational factors associated with concussion in cricket identified from video analysis

Video analysis of situational factors associated with head impacts and concussion has been completed in several sports, however has yet to be completed in cricket. This study aimed to identify situational factors associated with concussion in elite Australian male and female cricket. Match video of head impacts were coded for player position, impacting object, source of ball, location of impact, and where the ball went after impact. Head impacts were then categorised as either concussion or no concussion based on clinical diagnosis. Data for 197 head impacts included 35 (18%) which were diagnosed as concussion. Head impacts typically occurred to an on-strike batter facing a pace bowler (84%). If the ball stopped or rebounded towards the source, 21% were diagnosed as concussion (13% if the ball deflected away from the source). If impact was to an unprotected head, 38% were diagnosed as concussion (16% if impact was to a helmet). If impact was to the back of the helmet or head, 40% were diagnosed as concussion (11–21% for other areas of the head or helmet). The combination of situational factors most consistent with concussion were impact from ball that hit the back of helmet or head and stopped or rebounded towards the source (PPV 80%, p = 0.002). Consideration of the situational factors of a head impact may improve the speed and accuracy of clinical decision making on whether to remove a player from the field for further assessment, particularly if clinical signs are unclear. Video may be used as a tool to support this process. Improved impact attenuation of cricket helmets, particularly at the back, may reduce the risk of concussion.

Accident reconstructions of falls, collisions, and punches in sports

Objective

Impacts to the head are the primary cause of concussive injuries in sport and can occur in a multitude of different environments. Each event is composed of combinations of impact characteristics (striking velocity, impact mass, and surface compliance) that present unique loading conditions on the head and brain. The purpose of this study was to compare falls, collisions, and punches from accident reconstructions of sports-related head impacts using linear, rotational accelerations and maximal principal strain of brain tissue from finite element simulation.

Methods

This study compared four types of head impact events through reconstruction. Seventy-two head impacts were taken from medical reports of accidental falls and game video of ice hockey, American football, and mixed-martial arts. These were reconstructed using physical impact systems to represent helmeted and unhelmeted falls, player-to-player collisions, and punches to the head. Head accelerations were collected using a Hybrid III headform and were input into a finite element brain model used to approximate strain in the cerebrum associated with the external loading conditions.

Results

Significant differences ( p < 0.01) were found for peak linear and rotational accelerations magnitudes (30–300 g and 3.2–7.8 krad/s2) and pulse durations between all impact event types characterized by unique impact parameters. The only exception was found where punch impacts and helmeted falls had similar rotational durations. Regression analysis demonstrated that increases to strain from unhelmeted falls were significantly influenced by both linear and rotational accelerations, meanwhile helmeted falls, punches, and collisions were influenced by rotational accelerations alone.

Conclusion

This report illustrates that the four distinct impact events created unique peak head kinematics and brain tissue strain values. These distinct patterns of head acceleration characteristics suggest that it is important to keep in mind that head injury can occur from a range of low to high acceleration magnitudes and that impact parameters (surface compliance, striking velocity, and impact mass) play an important role on the duration-dependent tolerance to impact loading.

Equestrian Helmet Standards: Do They Represent Real-World Accident Conditions?

The use of helmets in equestrian sports has reduced the occurrence of traumatic brain injuries although, despite improvements to helmets, concussion remains a common injury. Currently, equestrian helmets are designed to pass certification standards involving a linear drop test to a rigid surface, while most concussions in equestrian sports result from oblique impacts to a compliant surface. The purpose of this study was to: (1) Compare the head kinematics and brain tissue response of the current equestrian helmet standard (EN1) and proposed standard EN13087-11 (EN2) to those associated with reconstructions of real-world equestrian concussion accidents. (2) Design a test protocol that would reflect the real-world conditions associated with concussion in equestrian sports. (3) To assess the protective capacity of an equestrian helmet using the flat turf and 45° turf proposed test protocols. Results for reconstructions of real-world concussions were obtained from a previous study (Clark et al. in J. Sci. Med. Sport 23:222-236, 2020). Using one jockey helmet model, impact tests were conducted according to the EN1 and EN2 protocols. Additionally, helmeted and unhelmeted tests were conducted at 5.9 and 6.0 m/s on to flat turf and 45° turf anvils for front, front-boss and rear-boss impact locations. The results demonstrated EN1 and EN2 both had higher magnitude accelerations and shorter duration impacts than reconstructed real-world concussive impacts. Impacts to turf anvils, on the other hand, produced similar head kinematics compared to the reconstructed real-world concussive impacts. Additionally, this study demonstrated that helmeted impacts significantly decreased rotational kinematics and brain tissue response below what is associated with unhelmeted impacts for oblique falls. However, the head kinematics and brain tissue response associated with these helmeted falls were consistent with concussion, suggesting that scope exists to improve the capacity of equestrian helmets to protect against concussion.

Development of a test method for adult ice hockey helmet evaluation

Ice hockey helmet standards have primarily been developed to reduce risk of traumatic brain injury (TBI). While severe TBI has become a rare event in ice hockey, concussion, a type of mild TBI, remains a common head injury. Concussions, in ice hockey result from a number of head impact events including, collisions, stick impacts, puck impacts, falls into the boards, impacts to the glass, and falls to the ice. Helmet testing methods need to represent the impact events creating concussions in ice hockey. The purpose of this research was to develop a helmet test protocol and performance metric for concussive impacts in ice hockey. A protocol using concussion impact parameters from published literature was created that used monorail and linear impactors to impact a helmeted Hybrid III headform. The linear and rotational acceleration time curves were then used to calculate brain tissue strain using the University College Brain Trauma Model. The proposed test protocols created kinematic responses that were representative of levels associated with concussion in ice hockey. Rotational velocity and rotational acceleration were both identified as useful performance metrics representing levels of risk for concussion.

Sensitivity and Specificity of On-Field Visible Signs of Concussion in the National Football League

BACKGROUND

On-field visible signs (VS) are used to help identify sport-related concussion (SRC) in the National Football League (NFL). However, the predictive utility of a VS checklist for SRC is unknown.

OBJECTIVE

To report the frequency, sensitivity, specificity, and predictive value of VS in a cohort of NFL athletes.

METHODS

On-field VS ratings from 2 experts who independently reviewed video footage of a cohort of 251 injury plays that resulted in an SRC diagnosis (n = 211) and no diagnosis (n = 40) from the 2017 NFL season were examined. The frequency, sensitivity, specificity, and a receiver operating characteristic (ROC) curve with area under the curve (AUC) were calculated for each VS.

RESULTS

Slow to get up (65.9%) and motor incoordination (28.4%) were the most frequent VS in concussed athletes, and slow to get up (60.0%) was the most common VS among nonconcussed athletes. The most sensitive VS was slow to get up (66%); the most specific signs in concussed NFL athletes were blank/vacant look and impact seizure (both 100%). Approximately 26% of concussed NFL players did not exhibit a VS, and the overall sensitivity and specificity for the VS checklist to detect SRC were 73% and 65%, respectively. The VS checklist demonstrated “poor” ability to discriminate between SRC and non-SRC groups (AUC = 0.66).

CONCLUSION

In the NFL, the diagnosis of concussion cannot be made from on-field VS alone. The VS checklist is one part of the comprehensive sideline/acute evaluation of concussion, and the diagnosis remains a multimodal clinical decision.

Analysis of team-sport wheelchair falls during the Rio 2016 Summer Paralympic Games: a video-based cross-sectional observational study

OBJECTIVES

To present the fall characteristics of athletes playing wheelchair rugby (WR) and wheelchair basketball (WB) using official videos from the Rio 2016 Paralympic Games and compare the key fall characteristics among the team wheelchair sports event.

METHODS

Eighteen WR and 10 WB game videos for men (MWB) and women (WWB), including 8 teams per sport, were obtained from the official International Paralympic Committee of the Rio 2016 Paralympic Games. The videos were analysed to assess the number of falls, playing time of fall, playing phase, contact with other athletes, the direction of the fall and the body part first in contact with the floor during the fall.

RESULTS

In total, 359 falls (96 for WR, 172 for MWB and 91 for WWB) occurred with a mean of 5.3, 17.2 and 9.1 falls per match, respectively (p<0.05). Significant differences among the three sports were detected in the playing time (p=0.011), presence of contact (p=0.037), direction (p<0.001) and body part first in contact with the floor (p<0.001). For WR, the falls were primarily lateral and caused by contact, occurring in the second half of the match. WB falls tended to be in the first half for women and the second half for men. Most falls were contact falls in the forward direction.

CONCLUSION

By observing the situational details, we described that a number of falls due to contact occurred during these team sports events, especially MWB. In addition, each sport exhibited characteristics attributable to differences in gender, degree of impairment and game rules. The directions of the falls and characteristics of the affected body parts indicate differences in impairments depending on the sport. A fall to the side or back may indicate a risk of injury.

Prevalence and Burden of Health Problems in Male Elite Ice Hockey Players: A Prospective Study in the Norwegian Professional League

Background

As previous epidemiological studies in elite ice hockey have focused on acute time-loss injuries, little is known about the burden of overuse injuries and illnesses in ice hockey.

Purpose

To report the prevalence and burden of all health problems in male professional ice hockey players in Norway during a single competitive season.

Study Design

Descriptive epidemiological study.

Methods

A total of 225 male ice hockey players in the GET League (the premier professional league) in Norway reported all health problems (acute injuries, overuse injuries, and illnesses) during the 2017-2018 competitive season. Players reported all injuries and illnesses for 31 weeks using the Oslo Sports Trauma Research Center Questionnaire on Health Problems.

Results

At any given time, 40% (95% CI, 37%-43%) of players reported symptoms from an injury or illness, and 20% (95% CI, 19%-22%) experienced health problems with a substantial negative impact on training and performance. Acute injuries represented the greatest incidence, prevalence, and burden (defined as the cross-product of severity and incidence). The most burdensome acute injuries were to the head/face, shoulder/clavicle, knee, and ankle. The most burdensome overuse injuries were to the knee, lumbar spine, and hip/groin.

Conclusion

This registration captured a greater burden from overuse injuries than traditional injury registration, but acute injuries did represent a major problem. These data provide guidance in the development of prevention programs for both acute and overuse injuries, which should focus on the lumbar spine, hip/groin, and knee.

Professional assessment of potential concussions in elite football tournaments

Background

Potential concussive events (PCEs) are a major health concern in football. Though there are protocols set in place for assessments of PCEs, there has been no evidence of adherence in major football tournaments.

Methods

Our research goal is to determine if PCEs in elite football are professionally assessed according to the International Conference on Concussion in Sport (ICCS) consensus statement recommendations. Identification and analysis of PCEs in the 2018 World Cup (WC) were accomplished through standardised observation of video footage by trained observers. Results were contrasted with data from the 2014 WC and 2016 Euro Cup. Our primary outcomes include frequency and professional assessment of PCEs, signs of concussions and time stopped for assessments.

Findings

In the 64 games of the 2018 WC, 87 PCEs (1.36 per game) were identified. Thirty-one (35.6%) PCEs were professionally assessed, resulting in the removal of three (3.5%) players from the match. Six (6.9%) PCEs showed one sign of concussion, 60 (69.0%) showed two signs, 20 (23.0%) showed three signs and 1 (1.2%) showed four or more signs. The mean time stopped for assessment was 63.3 s. No significant change in the percentage of professional assessments (mean=33.4%, 95% CI 20.7% to 46.1%) were identified across tournaments (p=0.42).

Interpretation

These findings demonstrate a need for adherence to concussion protocols in order to improve the brain-health of athletes. Proper enforcement of the ICCS protocols during these tournaments and promoting player health and safety can influence the officiating, coaching and playing of football worldwide by promoting player safety.

Characteristics of potential concussive events in three elite football tournaments

Objective

Identify patterns in the nature and characteristics of potential concussive events (PCEs) in football.

Methods

This study analysed the incidence and characteristics of PCEs that occurred during the 2014 and 2018 Fédération Internationale de Football Association World Cups, and the 2016 UEFA Euro Cup. PCEs were defined as direct head collision incidents resulting in the athlete being unable to immediately resume play for at least 5 sec following impact.

Results

A total of 218 incidents were identified in 179 matches (1.22 per match, 36.91 per 1000 hours of exposure). The most common mechanism of PCE was elbow-to-head (28.7%, n=68). The frontal region was the most frequently affected location of impact with 22.8% (n=54).

Conclusion

Our study defined the identification, prevalence and nature of PCEs in professional international soccer tournaments. Our findings indicate the different contexts and mechanisms of head contact and contact to different regions of the head can be associated with varying signs of concussion. The results highlight targets for future injury prevention strategies.

Exploring the role of cervical spine endurance as a predictor of concussion risk and recovery following sports related concussion

BACKGROUND

Concussions have become a significant public health concern with rising incidence rates. Concussions have been shown to occur concurrently with neck injuries, such as whiplash-associated-disorder, therefore, understanding the role of the neck in concussions is important.

OBJECTIVES

To determine if there is a relationship between cervical muscle endurance and either concussion incidence, or concussion recovery in university athletes. Specifically, the primary aim was to investigate a relationship between pre-season deep neck flexor endurance test (DNFET) time in those who sustained an in-season injury versus those who did not. The secondary aim is to determine correlation in DNFET times and concussion recovery.

DESIGN

Longitudinal observational study.

METHODS

Pre-season DNFET was performed on university athletes. In the event of a concussion, cervical endurance and neuromuscular adaptation was re-assessed with the DNFET. Rehabilitative exercises were prescribed, as required, and DNFET was measured at subsequent treatments.

RESULTS

There was no significant difference between pre-season DNFET times and concussion incidence (p = 0.55). However, there was a moderate correlation between DNFET times and concussion recovery (R = 0.47, p = 0.001) whereby DNFET times improved predictively throughout rehabilitation.

CONCLUSIONS

While no statistically significant relationship was found between DNFET and concussion incidence, a significant clinical relationship was present with recovery. The validity of the DNFET test as a means for assessing risk or measuring recovery requires additional research.

International consensus definitions of video signs of concussion in professional sports

BACKGROUND

The use of video to assist professional sporting bodies with the diagnosis of sport-related concussion (SRC) has been well established; however, there has been little consistency across sporting codes with regards to which video signs should be used, and the definitions of each of these signs.

AIM

The aims of this study were to develop a consensus for the video signs considered to be most useful in the identification of a possible SRC and to develop a consensus definition for each of these video signs across the sporting codes.

METHODS

A brief questionnaire was used to assess which video signs were considered to be most useful in the identification of a possible concussion. Consensus was defined as >90% agreement by respondents. Existing definitions of these video signs from individual sports were collated, and individual components of the definitions were assessed and ranked. A modified Delphi approach was then used to create a consensus definition for each of the video signs.

RESULTS

Respondents representing seven sporting bodies (Australian Football League, Cricket Australia, Major League Baseball, NFL, NHL, National Rugby League, World Rugby) reached consensus on eight video signs of concussion. Thirteen representatives from the seven professional sports ranked the definition components. Consolidation and refinement of the video signs and their definitions resulted in consensus definitions for six video signs of possible concussion: lying motionless, motor incoordination, impact seizure, tonic posturing, no protective action-floppy and blank/vacant look.

CONCLUSIONS

These video signs and definitions have reached international consensus, are indicated for use by professional sporting bodies and will form the basis for further collaborative research.

Concussion and National Hockey League Player Performance: An Advanced Hockey Metrics Analysis

CONTEXT

Postconcussion deficits in neurocognitive performance and postural control may persist at the time of return to sport participation. How these deficits, if present, affect athletic performance is largely unknown, with prior studies showing mixed results.

OBJECTIVE

To evaluate postconcussion National Hockey League player performance using advanced hockey metrics over short- (5 games), medium- (10 games), and long-term (remainder of the season) seasonal performance.

DESIGN

Retrospective cohort study.

PATIENTS OR OTHER PARTICIPANTS

National Hockey League players who sustained a sport-related concussion (SRC; n = 93) and returned during the same season and players (n = 51) who missed time for non-injury-related reasons.

MAIN OUTCOME MEASURE(S)

Six performance metrics were used: (1) points per 60 minutes, (2) Corsi percentage, (3) personal Fenwick shooting percentage, (4) scoring chances per 60 minutes, (5) penalty difference, and (6) PDO (not an acronym but sometimes referred to as SVSP% [save percentage shooting percentage]). Performance was compared using 2 (group) × 2 (time) repeated-measures analyses of variance for 3 time windows: (1) ±5 games, (2) ±10 games, and (3) the remainder of the season postconcussion. Alpha values were set at a conservative .01 to account for the lack of independence among dependent variables.

RESULTS

No significant interactions were present for any of the 6 dependent variables at any of the 3 time windows. Overall, none of the secondary variables differed.

CONCLUSIONS

Using advanced, sport-specific metrics, we found that National Hockey League players did not display worse seasonal performance during 3 postinjury time frames after they sustained an SRC. Whereas laboratory studies have identified lingering neurologic deficits after concussion, our results suggest that these deficits, if present, either do not translate to worse athletic performance or were not captured by these 44 metrics. Further, prospective efforts are needed to accurately quantify performance after SRC among professional hockey players.

Sideline assessment of concussion

The recognition and sideline evaluation of possible sport-related concussion are difficult tasks for a physician and other clinicians. Sideline assessment tools have continued to evolve over the years, but objective biomarkers of concussion do not currently exist. Sideline video review programs may aid in the recognition of possible concussion as additional information for the sideline athletic medicine staff. Additional investigational assessments include visual oculomotor processing, reaction time, and rapid eye movements and attention. As the presentation of concussion is variable and symptoms may evolve over time, it is important that athletes with possible concussion are followed with serial assessments. If the diagnosis is unclear, it is advised to err on the side of caution and not allow the athlete to return to competition on the day of the injury. This chapter will review the current issues regarding the sideline assessment of concussion.