Objective To describe the sequence of events leading to concussion in NHL players from 2014–15 to 2018–2019 and compare injury characteristics to prior to Rule 48 (i.e., Illegal Check to the Head).

Design Descriptive epidemiological study.

Setting National Hockey League (NHL) Video Analysis Program. Digital video records were coded and analysed using a standardised protocol.

Participants NHL players diagnosed with concussion where digital video footage of the injury was available (2014–19, n=516; 2006–2010 [before Rule 48], n=189).

Outcome Measures Player position, period, location, and sequence of events (e.g., player contact, environment, puck possession, game situation) were analyzed for frequency. Comparison to 2006–2010 data was done with randomly resampling (1000 iterations), akin to a one-sample t-test.

Main Results For 2014–19 seasons, sequence of events resulting in concussion were characterized by body checks (to the torso) around the perimeter of the ice. Compared to years 2006–2010, 2014--19 was characterized by significantly fewer concussions following open ice hits (47% vs. 37%; p<0.001), hits to the head via shoulder (42% vs. 31%; p<0.001), fights (9% vs. 3.3%; p<0.001), and lateral hits to head (35% vs. 21%; p<0.001). Concussive events were also less likely to occur in the first period (47% vs. 36%; p<0.001).

Conclusions This study describes several differences in the sequences of events leading to concussion during the 2014 – 2019 seasons compared to prior years (2006–2010) predating the implementation of Rule 48.