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

Abstract

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.

Keywords: concussion rate; home/away; length of game; national hockey league; player ice position and concussion; points scored; style of play; time of season; win/loss.

Figure 1. Concussion Rate Per Game

Concussion rate per game analyzed in both the regular season and postseason for the 2013-2017 NHL seasons. No concussions were documented in the 2015-2016 postseason utilizing the FOX Sports injury tracker.

Figure 2. Concussion Rate Across Major Contact Sports

Calculated concussion rate per game comparison between the National Hockey League (NFL), the National Football League (NFL), and Australian Football League (AFL). NHL, NFL and AFL concussion rate was determined by our research group in previously published works [8-11]. No statistical tests were run on this observational finding.

Figure 3. Home vs. Away Concussion Rate for 2013-2017 NHL Seasons

Analysis of the concussion rate/game from the home vs. away team perspective during the 2013-2017 NHL seasons. Results of this analysis demonstrated non-significance (p = 0.4584).

Figure 4. Win vs. Loss Impact on Concussion Rate

Analysis of the concussion rate/game from a win vs. loss perspective between the 2013 and 2017 NHL seasons. Results of this analysis demonstrated non-significant findings.

Figure 5. Average Points Scored Analysis

Analysis of average goals scored in games with or without concussion during the 2013-2017 NHL seasons. Results of the analysis indicated a non-significant difference (p = 0.3472)

Figure 6. Real Time Length of Game

Real time average length of game with and without a concussion during the 2013-2017 NHL seasons. Real length of game is comprised of three 20 minute periods and two 17 minute intermissions. We also considered TV time outs at minutes 10, 8 and 6 incorporated into the time. These TV time outs can span around 45 seconds to 2 full minutes. Final result was shown to be non-significant (p = 0.2069).

Figure 7. Time of Season Analysis

A) Time of season and reported concussion analysis for each individual season between 2013 and 2017. B) We noted no significance in the findings when comparing the first third of the season (Oct-Dec) to the final third of the season (Apr-Jun) (p = 0.7490). No significant difference was noted for the first third vs. the middle third (p = 0.4468).

Figure 8. On-ice Position Analysis

A) Evaluation of concussion incidence for on-ice positions during the 2013-2017 NHL seasons. B) Total number of concussions at each position was divided by total number of games in our data set (5281 games) to attain rate for the 2013-2017 seasons.