Analysis of Player Performance and Financial Costs Associated With Implementation of an Updated National Hockey League Concussion Protocol: A Retrospective Comparative Study.

Background: An updated National Hockey League (NHL) concussion protocol (NHLCP) was established in the 2016-2017 season to mitigate the negative outcomes of sport-related concussions. However, few studies on the effects of implementing the NHLCP have been performed. Purpose: To define concussion incidence and investigate differences in NHL player performance after a concussion during periods before and after NHLCP implementation and assess the financial impact on NHL teams associated with NHLCP implementation. Study Design: Cohort study; Level of evidence, 3. Methods: This was a retrospective review of NHL players who sustained a concussion before (2000-2001 to 2015-2016 seasons) and after (2016-2017 to 2020-2021 seasons) implementing the NHLCP (pre-NHLCP and post-NHLCP groups). For each group, multiple performance metrics-including 30 days, 1 season, and 3 seasons before and after concussion-were compared for both groups. Return to play, total concussion cost, and association of return to play with cost were investigated using regression analysis. Results: A total of 452 players (423 skaters, 29 goalies) sustained concussions during the study period, including 331 players (315 skaters, 16 goalies) in the pre-NHLCP group and 121 players (108 skaters, 13 goalies) in the post-NHLCP group. For both groups, no significant differences in standard performance were observed during the 30-day and 1-season periods before and after concussion. The mean return to play was significantly higher in the pre-NHLCP group than in the post-NHLCP group (20.1 vs 15.7 days; P = .022). The mean adjusted player salary was not different between groups; nonetheless, the mean adjusted replacement player salary was significantly higher in the post-NHLCP group ($744,505 vs $896,942; P = .032). The mean cost of time missed did not differ between groups. The mean return to play time significantly decreased over the entire study period (R2 = 0.33; P = .005), and the mean return to play time was positively associated with cost R2 = 0.215; P = .030). Conclusion: Concussion incidence did not change after implementation of the updated NHLCP; nonetheless, players had significantly less missed time from injury after protocol implementation. Changes in player performance 30 days and 1 year before and after concussion injury were not different before and after NHLCP implementation. No differences were found in the financial cost of concussions between the pre- and post-NHLCP groups, and missed time was significantly correlated with mean cost from missed time.

Return to Play, Performance, and Earnings Analysis After Lumbar Disc Herniation in National Hockey League Players.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Professional hockey players have a high incidence of lumbar disc herniations (LDH). The purpose of this study was to determine the impact of LDH on the performance and financial earnings of National Hockey League (NHL) players. METHODS: NHL players who sustained a LDH were retrospectively reviewed utilizing an online database and a 2:1 matched control cohort. Player performance and game usage was compared at one- and three-season(s) pre- and post-injury season within the cohorts. Injured and matched players were divided into 3 groups based on the player's adjusted index season salary. RESULTS: A total of 181 players were included, with 62 LDH players matched to 119 healthy controls. Return to play after LDH was 79%. The LDH cohort had fewer seasons played throughout their career compared to the matched group (12.5 ± 4.3 vs 14.2 ± 3.8; P = .031). At 1 season post-index, the LDH cohort had significantly fewer goals per 60 and points per 60 when compared to pre-index. At 3 seasons post-index, the LDH cohort exhibited a significant decline in time-on-ice per game played, goals per 60, and points per 60 compared to pre-index. CONCLUSION: The majority of NHL players who sustained a LDH returned to play (79%) but had shorter careers overall and decreased performance outcomes when compared to matched cohorts at both 1 and 3 seasons post-injury.

"This is fine": the impact of blowouts on subsequent game performance in the National Hockey League (NHL).

Blowouts in sports involve large margins of victory or loss between teams and have long been perceived as influencing subsequent performances by athletes, coaches, fans, and other stakeholders. Under the backdrop of the hot hand ph enomenon, the current study explores the impact of blowouts on subsequent game performance in the National Hockey League (NHL). Specifically, we examine the potential carryover of a "hot (or cold) hand" on the subsequent game following a large win or loss. In our study, we defined blowouts as outlying goal differentials for regular season games (i.e., a difference of approximately 6 goals between teams in a single game based on 3 standard deviations from the mean goal differential during the sampled period). Using this criterion, data from 285 games over the 2005-06 to 2018-19 NHL regular seasons were gathered for analysis. We performed a series of multiple regressions using blowout goal differential as the main predictor, adjusting for location of the subsequent game, number of time zones from the home base city, whether the subsequent game was a back-to-back, and winning percentages of the team and opponent. Our results revealed no significant over or under performance by teams that either won through a blowout or those that lost by a blowout. Our findings are consistent with previous work in other and similar sports contexts. Practical applications and future directions for research are discussed.

National Hockey League Fights per Game and Viewership Trends: 2000-2020.

Background: Though once considered an integral part of professional hockey, fighting carries significant health risks to players. Fighting has remained legal in the National Hockey League (NHL) due to its purported economic and entertainment value. However, fights per game have diminished over the past 20 years, challenging the necessity of fighting to promote fan attendance. Hypothesis: Despite decreasing fighting rates, attendance has been stable and is negatively associated with fights per game. Methods: Two public databases were reviewed to determine attendance, fighting majors, goals scored, and games played for each NHL team from 2000 to 2020 and averaged on a per game basis. Univariate analysis was used to evaluate relationships between attendance and fights, attendance and goals, as well as goals and fights. Results: Fights per game decreased from a peak of 0.64 in 2002 to a low of 0.18 in 2020, while average attendance increased from a low of 16,549 in 2004 to a peak of 17,768 in 2013, before settling between 17,400 and 17,500 during the final three seasons of the study period. A significant negative correlation was found between attendance and fights per game (R = -0.6617, p = 0.0020). There was a positive, but not significant correlation between attendance and goals per game (R = 0.2457, p = 0.3105). A significant inverse correlation existed between goals per game and fights per game (R = -0.521, p = 0.0222). Conclusions: NHL fighting rates have diminished during the past two decades, while fan attendance has increased. A significant negative correlation exists between fan attendance and fights per game, casting doubt on fighting's entertainment value. Meanwhile, a significant inverse correlation was noted between goals per game and fights per game. Taken together, these findings suggest fans may prefer higher scoring and less violent competitions. We conclude by suggesting that prohibiting fights in the NHL could improve player safety without negatively impacting fan attendance.

Hockey Puck Strike Rates and Injuries at National Hockey League Games: A Retrospective Analysis of Data from Six Seasons.

IMPORTANCE: This paper provides a large-scale, per-National Hockey League (NHL) season analysis of hockey puck strike (HPS) injury data and also provides estimates of injury frequency and severity. OBJECTIVE: The study's goal was to quantify and describe the rate and type of spectator HPS injuries at NHL games. DESIGN: This was a retrospective review of summary data reports for patients evaluated by on-site health care providers over six seasons (2013-2018). Data were obtained from a single Emergency Medical Service (EMS) agency. SETTING: Location of study was one US-based NHL venue. RESULTS: There were 51 HPS recorded. This accounted for 0.93% of total patient contacts translating to a patient per 10,000 (PPTT) of 0.116. This was compared to a PPTT of 12.6 for all patient contacts. The average age of a patron with a HPS was 31 years old. There was an even split between male and female patrons with HPS. The most common location for a HPS was the head or face (75%) followed by upper extremity injuries. Laceration was most frequently diagnosed followed by contusions and pain. Approximately one-quarter of people struck by hockey pucks were transported to the hospital, with the transport to hospital rate (TTHR) being 0.027, compared to the total TTHR of 2.7. CONCLUSIONS AND RELEVANCE: Hockey is a safe sport to watch, although HPS are the spectator hazard of concern given that pucks can travel into the stands at 100mph. Most injuries are minor and occur only one percent of the time; but when they do occur, these fans tend to need transport to the hospital. Finally, HPS tend to occur along the lateral sides of the rink where the glass level is lower and there is no protective netting.

Eliminating buyer's remorse: An examination of the sunk cost fallacy in the National Hockey League draft.

The sunk cost effect describes the tendency to escalate one's commitment toward a certain endeavor, despite diminishing returns, as a consequence of irreversible resource expenditure that has already been made (Organ Behav Hum Decis Process. 1985;35:124). This effect has been observed in a number of professional sports leagues, wherein teams escalate their commitment toward players selected early in the draft, regardless of performance outcomes, due to large financial commitments invested in them (J Sports Econom. 2017;18:282; Adm Sci Q. 1995;40:474). This effect, however, has yet to be explored in the National Hockey League (NHL). The purpose of this study was to test for sunk cost effects in the NHL, by examining the relationship between draft order and playing time, while controlling for a myriad of confounding variables. Findings from our analyses provide support for the existence of this effect in the NHL, as first-round draftees were given significantly more playing time than their peers selected in the second round, regardless of injury, player relocation, penalties, or on-ice performance outcomes. We offer some plausible underlying mechanisms driving this effect. Furthermore, we suggest the observed effects have valuable implications for NHL talent development, given the importance of playing time on various aspects of expertise attainment.

Accuracy from the slot: Evaluating draft selections in the National Hockey League.

The National Hockey League (NHL) entry draft is a process wherein teams make sequential selections from a pool of eligible players. Given the young age of prospects, drafting requires long-term forecasting of future performance under a high level of uncertainty. This study assessed the selection accuracy across all seven rounds of the draft, as well as between lottery and non-lottery picks within the first round. NHL performance data were collected for all forwards (N = 956) and defensemen (N = 558) drafted between 2007 and 2014. In both groups, Kruskal-Wallis H tests conducted between draft rounds revealed a significant, relatively strong, overall effect of draft order on future performance. However, Mann-Whitney U post-hoc tests showed projecting future performance of forwards was only accurate in the first two rounds, while for defensemen, selection was only accurate in the first round. Moreover, forwards selected with lottery picks in the first round outperformed their non-lottery peers offensively but not defensively. As for defensemen, those selected with lottery picks did not differ from their non-lottery peers in offensive or defensive performance. Our findings highlight substantial inaccuracies in the NHL draft, particularly past the first two rounds of selection. We offer multiple possible explanations driving such inaccuracies that could form the basis for further work in this area.

The Impact of Participation in the Olympics on Post-olympic Performance in Professional Ice Hockey Players.

The 2014 Sochi Winter Games were the last Winter Olympics where NHL players were allowed to compete. One explanation for prohibiting NHL players from participating in the Winter Olympics is a perceived negative impact on their performance post-Olympics, owing to the additional fatigue of participating. The purpose of this study was to explore whether participation in the 2014 Sochi Winter Games negatively impacted individual NHL player performance post-Olympics. A database was constructed to examine NHL player points per game played as the performance outcome pre- and post- the 2014 Winter Olympics during the 2013-2014 NHL season. Three multilevel models were fitted with post-Olympics points per game as the outcome. Model 1 examined the effect of Olympic minutes played, controlling for pre-Olympics points per game. Model 2 introduced player position (forward vs. defense) and model 3 included an interaction between player position and Olympic minutes played to determine if there were differential effects of Olympic participation on post-Olympic performance by position. The results show that Olympic minutes played did not have a significant main effect on post-Olympics performance (p > 0.10). There was a significant interaction between Olympic minutes played and playing position whereby forwards who played a higher number of minutes in the Olympics scored fewer points per game post-Olympics than forwards playing fewer Olympic minutes. The magnitude of this effect, however, was quite small [b (SE) = -0.003 (0.001), p = 0.03]. These findings suggest that the effect of Olympic playing time on individual player performance post-Olympics is minimal.

Shoulder instability, performance, and return to play in National Hockey League players.

BACKGROUND: The shoulder is a commonly injured area in hockey, yet information is lacking on the prevalence and effect of shoulder instability. Our study investigates the incidence of shoulder dislocation events in the National Hockey League (NHL) and the effects on return-to-play (RTP) and player performance. We hypothesize that NHL players would have high RTP rates without significant changes in performance after injury. METHODS: NHL players who suffered in-season shoulder instability events between 2003-2004 and 2017-2018 seasons were identified. Demographic characteristics, incidence of injury, recurrences, RTP, and statistical performance data were collected. Postinjury performance was compared with experience-matched, era-matched, position-matched, and age-matched controls. A mixed generalized linear regression model was used to compare postinjury performance as a function of operative and nonoperative treatment. RESULTS: A total of 57 players experienced 67 shoulder instability events with 98.5% of players returning to play after an average of 26.3 ± 20.8 regular season games missed. Surgery was performed in 47.8% of players with no recurrent injuries postoperatively. Nonoperatively managed players experienced a decrease in points per game (P = .034) compared with surgically treated patients. Recurrence occurred in 14.3% of conservatively managed players, with 33.3% experiencing a season-ending injury. Players with recurrent injuries missed significantly more career games compared with those treated initially with surgery (P = .00324). CONCLUSION: Professional hockey players experience high rates of RTP with acceptable performance outcomes after shoulder instability events; however, recurrent injuries led to significantly more career games missed when treated nonoperatively at the time of injury.

A Systematic Review of the Orthopedic Literature Involving National Hockey League Players.

BACKGROUND: Orthopedic injuries of National Hockey League (NHL) players are common and may significantly affect players' health and careers. Evidence-based injury management is important in guiding players' timely return to sport and their ability to play at their pre-injury levels of competition. PURPOSE: To summarize all data published between January 1980 and March 2020 on orthopedic injuries experienced by professional ice hockey players competing in the NHL. STUDY DESIGN: Systematic review. METHODS: A literature review of studies examining orthopedic injuries in the NHL was performed using the Embase, PubMed, and CINAHL databases. The review included studies focusing on NHL players and players attending the NHL Combine and preseason NHL team camps. Studies pertaining to non-orthopedic injuries and case reports were excluded. RESULTS: A total of 39 articles met the inclusion criteria and were analyzed. The articles were divided by anatomic site of injury for further analysis: hip and pelvis (24%), general/other (14%), ankle (10%), knee (10%), foot (7%), shoulder (7%), thigh (7%), trunk (7%), spine (6%), elbow (4%), and hand and wrist (4%). The majority of articles were Level IV Evidence (51.3%), followed by Level III Evidence (38.5%). Most studies obtained data from publicly available internet resources (24.7%), player medical records (19.5%) or surveys of team physicians and athletic trainers (15.5%). A much smaller number of studies utilized the NHL Injury Surveillance System (NHLISS) (6.5%) or the Athlete Health Management System (AHMS) (2.6%). CONCLUSION: This systematic review provides NHL team physicians with a single source of the current literature regarding orthopedic injuries in NHL players. Most research was published on hip and pelvis (24%) injuries, did not utilize the NHLISS and consisted of Level IV Evidence.

High Ankle Sprains in Professional Ice Hockey Players: Prognosis and Correlation Between Magnetic Resonance Imaging Patterns of Injury and Return to Play.

BACKGROUND: Hockey players sustain a greater incidence of ankle syndesmosis injuries than other athletes. These injuries have a higher morbidity and more unpredictable recovery than lateral ankle sprains. Magnetic resonance imaging (MRI) has been used to establish the diagnosis but has not been evaluated for its ability to predict return to play. HYPOTHESIS: We hypothesized that patterns of injury defined on MRI could be used to predict return to play in a cohort of professional hockey players with syndesmosis sprains. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A prospectively collected National Hockey League (NHL) database was analyzed from the 2006-2007 to 2011-2012 seasons to assess return to play after an injury. A separate retrospective review of ankle MRI scans from professional hockey players with a documented high ankle sprain sustained between 2007 and 2012 was performed. Injuries were classified on MRI as complete or partial tears of the anterior-inferior tibiofibular ligament (AITFL), posterior-inferior tibiofibular ligament (PITFL), anterior talofibular ligament (ATFL), posterior talofibular ligament (PTFL), calcaneofibular ligament (CFL), and deltoid ligament. Fractures, bone contusions, and osteochondral lesions were also recorded. RESULTS: A total of 105 NHL athletes sustained high ankle sprains over the 5 seasons studied. Of these athletes, 85 were unable to play and missed a median of 8 games (range, 0-65 games). A retrospective MRI evaluation of 21 scans identified complete AITFL tears in 13 (62%) and high-grade partial tears in 5 (24%) cases. In contrast, the PITFL was partially torn in 9 (43%) and normal in 12 (57%) cases. Bone contusions were seen in 71% of cases and lacked a consistent pattern. The most commonly associated ligamentous injury was of the ATFL, which was injured in 52% of cases (11/21; 3 complete and 8 partial). There was no difference in the mean number of days lost when players were stratified by patterns of injury (incomplete/complete AITFL tear ± additional ligamentous injury, bone contusion, syndesmosis width). CONCLUSION: A high ankle sprain resulted in significant variations in time of recovery among professional hockey players. A torn AITFL and bone bruising were the most common patterns of injury. Although MRI can be used to confirm the diagnosis of a syndesmosis injury, it did not predict return to play in this population.

Return to elite-level sport after clavicle fractures.

OBJECTIVE: To determine if return to sport following clavicle fracture occurs earlier in high-level sports than the current standard of care allows for. DESIGN: Observational study retrospective review of NHL prospective data. SETTING: The study was performed at a university orthopaedic surgery department. PATIENTS: NHL player with clavicle fracture. ASSESSMENT OF INDEPENDENT VARIABLES: The independent variable including time on injured reserve and type of treatment. MAIN OUTCOME MEASURES: The primary study outcome measure was successful return to NHL play. RESULTS: 15 athletes were identified; 10 were treated operatively and 5 non-operatively. The average return to ice hockey was 10 weeks. If the one outlier is removed, the average is 9.1 weeks. There was one re-fracture in the non-operative group. The average time from injury to return to sport was 65 days in the operative group and 97.6 days in the non-operative group. Two patients were unable to return play during the same season. CONCLUSIONS: High-end athletes safely return to at-risk sports after clavicle fracture much sooner than the average seen with non-elite athletes. Additional study may demonstrate that return to activity can likely be accelerated without significantly increasing complications.

The Effects of Altitude on Concussion Incidence in the 2013-2017 National Hockey League Seasons.

Background and objective The high incidence of traumatic brain injuries during contact sports has necessitated the need for further research pertaining to their implications and possible mitigation. Despite increasing attention to sports-related concussions, there is still a striking lack of detail pertaining to the environmental factors that contribute to their occurrence. One environmental condition that has yet to be considered is altitude. Altitude cannot be readily adjusted, yet can still impact quality of play and concussion incidence. The current body of published evidence evaluating environmental effects on concussion is divided on the degree to which altitude mitigates concussion incidence. We aim to systematically compare the prevalence of concussions that occur at high and low altitude utilizing 1000 feet (304.8 meters) as a cut-off marker for high altitude. Our research also takes a novel approach utilizing average games missed as a proxy for concussion severity. We hope to use this analysis to shed light on the implication of altitude on concussion incidence. Methods Individual player data on concussion incidence were retrospectively acquired for the 2013-2017 National Hockey League (NHL) seasons utilizing FOX Sports Injury tracker. NHL season schedules were acquired through the online source "Hockey Reference." In order to establish cutoff criteria for high vs low altitude we adopted 1000 feet (304.8 meters) as high-low altitude cutoff. We also evaluated our data utilizing a previously published high-low altitude cutoff of 644 feet (196.3 meters). Specific altitudes of each NHL arena were derived from "elevationmap.net". One caveat to our data collection was the striking lack of publicly available data pertaining to the concussions sustained by each NHL team. Data was analyzed utilizing SAS programing. Results Out of the 5281 games included in our data set, we documented a total of 133 concussions which occurred in 125 games through the 2013-2017 NHL seasons. We noted an increase in concussion reporting in the most recent 2016-2017 NHL season compared to the previous 2013-2016 seasons. Effect of altitude variance on concussion rate was evaluated utilizing 644 and 1000 ft as the low-high altitude split. We defined each variance by where the team is based at compared to where the game was played. This produced four distinct categories: 1) low-low altitude, 2) low-high altitude, 3) high-low altitude, and 4) high-high altitude. We noted a significant difference in concussion rate when teams based at high altitude above 1000 ft travel to play at low altitude; this trend was non-significant at 644 ft. The results of the average games missed analysis demonstrated that teams that play above 1000 feet had fewer games missed per concussion compared to teams that are based at a low altitude. Conclusions Though underreported in the total number of concussions in the 2013-2017 NHL seasons, our data suggests that teams who are based at a high altitude (>1000ft) experience a reduction in mean concussion rate when traveling to play at a lower altitude. Our data also indicated a reduction in average games missed post-concussion for teams based at a higher altitude. It is our goal that our findings here contribute to the larger discussion about concussion incidence and can be applied to other sports leagues and activities to mitigate their dangerous effects.

Modifying Factors for Concussion Incidence and Severity in the 2013-2017 National Hockey League Seasons.

Introduction In the past few years, there has been a rising interest in both the prevalence and the short- and long-term consequences of concussions. While the main focus of concussion-based research revolves around the National Football League (NFL), attention is now shifting to other high contact leagues like the National Hockey League (NHL), where there is constant player-to-player contact as well as collisions with the perimeter boards. While the body of evidence surrounding injury and concussion rates in the NHL has substantially grown in size over the previous few years, there is still a void pertaining to the in-game effects that could modulate concussion incidence. Our study takes a novel approach to evaluate several "style of play" factors such as home/away perspective, win/loss outcome, points scored, real time length of game, time of season, and player position in modulating concussion rates. Methods Data on concussion incidence for the 2013-2017 National Hockey League seasons was collected utilizing FOX Sports injury tracker. Only injuries specifically diagnosed as concussions during regular and postseason games were utilized in our data set. A Google search on the reported injury was performed in order to correlate the concussion to the correct game in which the player sustained it. NHL season schedules were acquired through the online source "Hockey Reference." There were a total of 5281 games when considering the regular and postseason games between the 2013-2017 seasons. Concussions sustained during team practices and preseason contests were not accounted for in our data set to control for inconsistent reporting. Our data set does not account for the current 2017-2018 NHL expansion with the addition of a Las Vegas team to the league. Results Statistical analysis of several "Style of Play" factors such as home/away perspective, win/loss outcome, points scored, real time length of game and time of season produced non-significant results pertaining to modulating concussion rate during the 2013-2017 NHL seasons. When evaluating on-ice position we noted offensive players combined to have the highest rate of concussion. Forwards (left wing (LW), right wing (RW)) demonstrated similar concussion rates, while goalies encountered the lowest concussion rate. Conclusion The results of our analysis demonstrated non-significance for home/away effects, win/loss results, average points scored, real time length of game, and time of season on influencing concussion rates. We noted offensive players combined to have the highest rate of concussions, while goalies encountered the least. The key limitation in our data set is the lack of reliable and publicly available data surrounding concussion incidence in the National Hockey League. Due to this drawback, our data set should be considered as an under-reported representation of the total amount of concussions spanning the 2013-2017 seasons.

Beyond the game: the legacy of Bill Masterton.

Bill Masterton is the only man to die of injuries sustained in a National Hockey League (NHL) game. He remains the last fatality in any professional team sport involving a direct in-game injury in North America. While Masterton was originally thought to have suffered a fatal brain injury while being checked on the ice, later analysis of the case revealed evidence of second-impact syndrome and the effects of prior concussions. Masterton's death sparked both an immediate debate in the NHL on whether helmets should be compulsory and the NHL's first vote on mandatory helmet use. Although the subject of mandated helmet use met with resistance in the 10 years after Masterton's death, especially from hockey owners and coaches, the NHL finally legislated helmet use by all players entering the league beginning in the 1979-1980 season. Several awards, including one recognizing the NHL player who best exemplifies the qualities of perseverance, sportsmanship, and dedication to hockey, have been created in memory of Masterton. However, his legacy extends far beyond the awards that bear his name. His death was the seminal event bringing head safety to the forefront of a game that was both unready and unwilling to accept change. An increase in mainstream media attention in recent years has led to unprecedented public awareness of brain injury and concussion in hockey and other sports. Advances in the diagnosis and treatment of head injury in sports have occurred recently, the impetus for which started over 45 years ago, when Bill Masterton died.

Performance and Style of Play After Returning From Concussion in the National Hockey League.

BACKGROUND: Few studies have empirically examined outcomes of concussion in the National Hockey League (NHL) and whether these athletes return to games after concussion at a performance level comparable to preconcussion play. HYPOTHESIS: NHL players would not demonstrate changes in performance or style of play after returning from a concussion when compared with a group of control athletes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: NHL players with a reported hockey-related concussion during the 2008-2009 through 2014-2015 seasons were identified utilizing secondary media sources. Players who missed games for non-injury related causes were selected as the control group. "Performance" was operationally defined as the statistics for goals, assists, points, plus-minus, and shots, and "style of play" was operationally defined as the statistics for penalty minutes, blocked shots, hits, giveaways, and time on ice. Each gameplay statistic was recorded and totaled for the 5 games before and after each player's injury or absence. After meeting strict inclusion criteria, the 2 groups were compared across each postconcussion/absence statistic by generalized linear models while incorporating the particular preconcussion/absence statistic, position played, games missed, and concussion history as covariates to control for intraplayer and between-group differences. RESULTS: A total of 287 players sustained a concussion; 130 missed time for non-injury related reasons and were identified as controls. After the exclusion criteria were applied, 94 concussed players were compared with 58 controls. None of the models reached statistical significance, indicating that the concussion and control groups did not differ across performance or style of play after returning from a concussion or non-injury related absence. CONCLUSIONS: When compared with a control group, players who returned to consistent play after concussion did not demonstrate changes in performance or style of play.

The Sport Concussion Assessment Tool: a systematic review.

OBJECTIVE Over the last 2 decades, sport-related concussion (SRC) has garnered significant attention. Even with increased awareness and athlete education, sideline recognition and real-time diagnosis remain crucial. The need for an objective and standardized assessment of concussion led to the eventual development of the Sport Concussion Assessment Tool (SCAT) during the Second International Conference on Concussion in Sport in 2004, which is now in its third iteration (SCAT3). In an effort to update our understanding of the most well-known sideline concussion assessment, the authors conducted a systematic review of the SCAT and the evidence supporting its use to date. METHODS English-language titles and abstracts published between 1995 and October 2015 were searched systematically across 4 electronic databases and a review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines adapted for the review of a heterogeneous collection of study designs. Peer-reviewed journal articles were included if they reported quantitative data on any iteration of the SCAT, Standardized Assessment of Concussion (SAC), or modified Balance Error Scoring System (mBESS) data at baseline or following concussion in an exclusively athlete population with any portion older than 13 years of age. Studies that included nonathletes, only children less than 13 years old, exclusively BESS data, exclusively symptom scale data, or a non-SCAT-related assessment were excluded. RESULTS The database search process yielded 549 abstracts, and 105 full-text articles were reviewed with 36 meeting criteria for inclusion. Nineteen studies were associated with the SAC, 1 was associated with the mBESS exclusively, and 16 studies were associated with a full iteration of the SCAT. The majority of these studies (56%) were prospective cohort studies. Male football players were the most common athletes studied. An analysis of the studies focused on baseline differences associated with age, sex, concussion history, and the ability to detect an SRC. CONCLUSIONS Looking toward the upcoming Concussion in Sport Group meeting in fall 2016, one may expect further revision to the SCAT3. However, based on this systematic review, the authors propose further, in-depth study of an already comprehensive concussion test, with acute, diagnostic, as well as long-term use.

Prevalence of Vitamin D Insufficiency in Professional Hockey Players.

BACKGROUND: Vitamin D is a fat-soluble hormone that plays a role in bone health, muscle function, and athletic performance. Studies have shown that low levels of vitamin D can lead to slower muscle recovery and function, increased rates of stress fractures, and even poorer athletic performance. Insufficient vitamin D levels have been demonstrated in professional basketball and football players, however, there have been no studies to date reviewing vitamin D insufficiency in professional hockey players. PURPOSE/HYPOTHESIS: The purpose of this study was to perform a cross-sectional review to determine the prevalence of vitamin D deficiency and insufficiency in professional hockey players. The hypothesis was that there would be a high percentage of players with vitamin D insufficiency. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: The preseason serum 25-hydroxy (OH) vitamin D laboratory test results of 105 professional hockey players were retrospectively reviewed. All players on 3 National Hockey League (NHL) teams were included. Player parameters evaluated included age, height, weight, body mass index, and 25(OH) vitamin D level. Players were divided into 4 groups based on serum vitamin D levels: deficient (<20 ng/mL), insufficient (20-31.9 ng/mL), sufficient (≥32 ng/mL), and ideal (≥40 ng/mL). Descriptive statistics were performed, in addition to 2-group and 3-group comparisons. RESULTS: The average 25(OH) vitamin D level of 105 players was 45.8 ± 13.7 ng/mL (range, 24-108 ng/mL). No players in the study were considered deficient. A total of 14 players (13.3%) were considered insufficient, while 91 players (86.7%) were considered sufficient. However, only 68 players (64.8%) were considered ideal. When comparing groups, athletes with sufficient vitamin D levels were older than athletes with insufficient vitamin D levels (25.9 vs 23.1 years; P = .018). All other player parameters demonstrated no significant difference between groups. CONCLUSION: Despite playing a winter sport and spending a great deal of time training indoors, professional hockey players have low levels of vitamin D insufficiency.

Concussion in the National Hockey League: a systematic review of the literature.

Players in the National Hockey League (NHL) are often sidelined by injuries, including concussion. The acute, intermediate and long-term effects of repetitive head trauma remain a concern of many. In 1997, the NHL and NHL Players Association established the NHL-NHL Players Association Concussion Program to diagnose, assess and treat concussion via a standardized and scientific approach. Documenting and analyzing the trends, incidence and underlying mechanisms of concussion may help in devising future prevention and treatment plans for concussion in hockey in general and the NHL in particular. The purpose of this study, therefore, was to systematically review and summarize the existing published literature on the trends, incidence rates and underlying mechanisms of concussion in the NHL.

Stages and demands in the careers of Canadian National Hockey League players.

Researchers have identified some demands of Canadian National Hockey League (NHL) players, yet there is little direction for players hoping to reach the lucrative league. The objectives of this study were to identify the stages, statuses and demands in Canadian NHL players' careers and propose an empirical career model of Canadian NHL players. In total, 5 rookies, 5 veterans and 13 retirees had their interviews undergo an interpretive thematic analysis. Prospects face the NHL combine, training camp and minor league assignment. While developing into NHL players, rookies deal with NHL call-ups, team competition and formative production while sophomores seemed preoccupied by the opposition. Prime veterans become All-Stars by garnering point production and challenging for the Stanley Cup while seasoned veterans remain relevant through training camps. A discussion about the model's viability is followed by applications for sport psychology researchers and practitioners.