"Rugby: Head impact study says players' cognitive function can decline after one season"

Some studies suggest professional rugby players may be exposed to 11,000 contact events per season, and more research is beginning to show evidence that it may not be concussions alone that could impact the brain, but the cumulative effect and volume of contact events too.

The peer reviewed University of South Wales study, which is funded by the Royal Society Wolfson Research Fellowship, recorded six concussion incidents among all the players that took part over the course of the year.

However, all of those involved in the study saw a decline in blood flow to the brain and cognitive function between pre and post-season results.

Related: Chronic traumatic encephalopathy in sports