Video report by Granada Reports Sports Correspondent Mike Hall
A charity has been warning the stars of the Wigan Warriors rugby league team about the dangers of head injuries for their long-term health.
The 'Rugby League Cares' charity has delivered this presentation to every Super League player.
While there is no direct link between concussion and memory loss, there are growing concerns some players will be affected in later life.
The players were given a simple message, if you think you're concussed, leave the pitch.
Keith Senior from Rugby League Cares said: "It's their decision on the field. But if they're showing symptoms it's taken out of their hands by doctors and medics.
"There's times when they could be concussed and don't 100% know. You can get away with it at times."
Statistics reveal 20% of current players have played on with a concussion. The reasons they gave were that they didn't want to let the team down or be ruled out for the next match.
Lachlan Coote was a fullback for St Helens and was forced to retire early due to repeated concussions.
Lachlan said: "Rugby league has been part of my life since I was eight years old. When you've got family and kids and 60 more years to live, I think rugby is only a small part of that."
Warriors captain Liam Farrell said: "I think we are getting better. I'm guilty of this sometimes, there is an ego there - you don't want to let your team mates down. You want to compete.
"It's not about staying on the field, it's about looking after your brain and your health. It's definitely still an area to improve."
Rugby League has made changes to protect its players. There are now more rest days between games, fewer Easter fixtures, less contact in training and more recovery time for concussions.
Players are being asked to support new research, by sharing their own experiences of concussion and taking up the offer of MRI scans after picking up a head injury.
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