2015
A systematic review of concussion in rugby league.
The incidence rates vary across match play versus training session, seasons (winter vs summer) and playing position (forwards vs backs). The ball carrier has been found to be at greater risk for injury than tacklers. Concussion accounts for 29% of all injuries associated with illegal play, but only 9% of injuries sustained in legal play.
Concussion in youth rugby union and rugby league: a systematic review.
equivalent to a probability (of sustaining a concussion) of between 0.3% and 11.4% for rugby union and of 7.7% and 22.7% for rugby league.
2014
A systematic review and meta-analysis of concussion in rugby union.
there appears to be a variation in risk of concussion across level of play, with the sub-elite level having the greatest incidence of injury
Concussions in Community-Level Rugby: Risk, Knowledge, and Attitudes
The biomechanics of concussion in unhelmeted football players in Australia: a case-control study.
As hypothesised by Holbourn over 70 years ago, angular acceleration plays an important role in the pathomechanics of concussion, which has major ramifications in terms of helmet design and other efforts to prevent and manage concussion.