Jeff Parker. Reggie Fleming. Rick Martin. Bob Probert. Derek Boogaard. Larry Zeidel. Steve Montador.

 

All of these men have something in common. All of them played in the National Hockey League (NHL)  for five or more seasons. All of them were posthumously diagnosed with CTE.

 

Head trauma in hockey can happen anywhere on the ice, whether it be a collision between players or a player collision with the rink structures.

 

A 2001 study by David Goodman, Michael Gaetz and Daniel Meichenbaum that examined concussions in Canadan Amatuer hockey outright stated, “The greatest cause of concussion was contact with the ice and/or the boards.”

 

Bert Lenz, the director of Sports Medicine for Olympic Sports at Boston College, called repetitive head trauma “part of the sport” and identified defensemen as the most likely candidates to be on the receiving end.

 

“It’s probably player-to-player or player-to-glass with a defenseman going back and getting the puck,” said Lenz, “I don’t know any numbers off the top of my head and I haven’t seen any research based on the position in hockey, but to me the defensemen are the most susceptible to not having control because they’ve got to look down, play the puck with their back to the player coming behind them so it’s gonna be hit or miss. They can make a clean play and then still get hit, or they can end up eating a puck, lose control of the puck and their feet, and then they’re getting hit regardless.”

 

Mitchell Denhartog, who has served as an ice hockey referee for 14 years, spoke with me about his experiences as one of the closest observers of the sport. He identified checking as the most dangerous interaction between players: 

 

"Easily one of the most often interaction in hockey would be checking in the game. The issue I tend to see is bad form or dangerous checks. These tend to arise from either poor hitting form or intent to punish a player for a variety of reasons."

 

Fighting in Ice Hockey

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Fighting is more closely associated with hockey than any other non-combat sport. The comedian Rodney Dangerfield communicated this relationship when he said, “I went to a fight the other night, and a hockey game broke out.”

 

While the Goodman, Gaetz and Meichenbaum study states, “Fighting was not a major cause of concussion,” pugilistic interactions are known to contribute to CTE — demonstrated in boxing culture in the 1920s — likely through subconcussive impacts.

 

It is worth noting that three of the professional hockey players that have been diagnosed with CTE — Bob Probert, Derek Boogaard and Reggie Fleming — were notable fighters in the NHL.

 

During the 2017-18 season, HockeyFights.com recorded 280 fights between players. That is the fewest fights in a single season since the site began compiling this data in 2000. The NHL has averaged 553.7 fights per season since the turn of the century.

 

Even if ice hockey officials found a way to eliminate fights altogether, a 2016 study has determined that that change alone could lead to more physically aggressive play. Gregory DeAngelo, Brad R. Humphreys and Imke Reimers published results that indicated that the number of hits in an NHL game are actually reduced for up to ten minutes following a fight. Without fighting, the study indicates, games would include a higher sustained level of hits.

 

 

Hitting in Ice Hockey

 

As Lenz hinted at, hits are an important part of the game of ice hockey. Hits are a statistic that some sports statistical databases record and use as a metric for the success of NHL defenders. Teams with more hits are perceived as better defensive teams.

 

According to statistics compiled by Fox Sports, NHL players committed an average of 1.18 qualified hits per game during the 2017-18 season. A qualified hit is considered a valid check on a player who has possession of the puck. There are 82 games in an NHL season, and the average NHL career lasts five and a half seasons, according to RAM Financial Group. If a player averages 1.8 hits per game in an 82-game season for five seasons, he will average 400 qualified hits in his hockey career.  

 

This number, 400 career hits, completely leaves out hits that do not hit the statistics books as “qualified.” Four hundred collisions would be the baseline statistic. Add to that the number of illegal hits, accidental collisions, and player-rink collisions, and that number can rise well over 500 career interactions that could be potentially be classified as concussive or subconcussive interactions.

 

At present, there is no determined number as to how many hits, concussive or subconcussive, cause CTE.