According to a new study, the effects of collisions on professional rugby union players can cause a decrease in blood flow to the brain over the course of a season.
The study, conducted by University of South Wales (USW) researchers and published in the Journal of Experimental Physiology on Wednesday, looked at 21 players over the course of a single season with 31 games.
All of the participants — 13 forwards and eight backs — saw their brain function deteriorate, including their ability to reason, remember, formulate ideas, and carry out mental tasks.
According to a press release from the University of South Wales, the study is the first to show how repeated contact in rugby games and training can result in reduced blood flow to the brain over the course of a season.
“What we’re focused on here is the contact events as a result of scrummaging, rucking, mauling, tackling collisions,” Professor Damian Bailey, one of the authors of the study, told CNN Sport.
“We feel that it’s the recurrency, the chronic exposure … that ultimately culminate in causing an impairment in blood flow, and as a result, fuel delivery — oxygen and glucose delivery — to the brain, which in the long term, we feel can contribute to an impairment in cognitive function.”
The players in the study were part of a team that competed in the United Rugby Championship, which is a professional league that includes clubs from Wales, Ireland, Scotland, South Africa, and Italy.
According to Professor Bailey, each player in the study was exposed to 11,000 contact events per season. He advocates for more screening of rugby players in order to better understand the long-term effects of these repeated collisions.
“We religiously measure strength, we religiously measure cardiorespiratory fitness, but we never assess brain fitness or health,” added Professor Bailey.
“We’re still at the very beginning of trying to understand what happens to the rugby player’s brain, but I think there’s sufficient evidence for us to be a little bit concerned and to look at ways of improving the safety, not just in-game, but out-of-game as well.”
The consequences of repeated head hits in American football have been well documented. The NFL and more than 5,000 former players settled a class-action lawsuit in 2015, awarding up to $5 million per retired player for serious medical conditions linked to repeated head trauma.
A group of former rugby players filed a lawsuit against the sport’s governing bodies last year over the issue of degenerative brain disease.
In their early 40s, some of the former players were diagnosed with early onset dementia and likely chronic traumatic encephalopathy (CTE), a progressive, degenerative brain disease caused by repeated head hits.
For several years, elite rugby teams have used a Head Injury Assessment (HIA) protocol during games to identify and manage the impact of head injuries.
World Rugby, the sport’s global governing body, stated on Tuesday that “welfare will always be our number one priority.”
A statement added: “World Rugby recently committed to double our investment in player welfare and new concussion research and initiatives.
“We are currently undertaking a wide-ranging evaluation of contact training volume across the game and look forward to the results of the ongoing Otago Rugby Community Head Impact Detection study, which is the largest ever study of playing and training head impacts in men’s and women’s community rugby.”