Objective To assess and evaluate the injury risk associated with the scrum in English professional rugby union in the 2011–2012 season.

Design Prospective, cohort.

Participants Players at English Premiership rugby union clubs.

Outcome measures Frequency of team scrum-events per match; incidence (injuries per 1000 player-hours; propensity (injuries/1000 events); risk (days absence per 1000 player-hours and days absence per 1000 events).

Results 31% of scrums in competitive matches resulted in collapse. Injury incidence associated with collapsed scrum-events (incidence: 8.6 injuries/1000 scrum-events) was significantly higher than those scrums that did not collapse (incidence: 4.1/1000 scrum-events).

Conclusions The injury risk associated with collapsed scrum supports the continued focus on reducing scrum collapse through changes in, and strict application of, the laws surrounding the scrum.