Two American Football stars say they will donate their brains for medical research after their deaths.
New York Giants punter Steve Weatherford and former Seattle Seahawks receiver Sidney Rice want to support studies into brain injuries.
Many former players in the sport suffer degenerative brain disease.
"There are a lot of issues that stem from brain injuries and it's not just professional athletes. This affects everybody," Weatherford said.
Rice won the Super Bowl with the Seattle Seahawks last year before retiring - at the age of 27 - over fears for his long-term health after absorbing so many blows to the head.
Both he and Weatherford said they hoped their commitment could persuade others to support research into brain injuries.
About 4,500 former players are suing the National Football League (NFL) over head injuries suffered during their careers. They are close to a settlement worth about $1bn (£655m).
"A lot of my team-mates and a lot of close friends have dealt with concussions and the depression that comes with that," said Weatherford.
The pair made a joint announcement to coincide with Brain Injury Awareness Month in the US.
Rice estimates he suffered between 15 and 20 concussions playing American Football from the age of eight.
"I had my fair share of fun in the NFL," he said. "Unfortunately, I wasn't educated enough on what concussions can lead to. The brain studies by the doctors will be huge to help, maybe prevent."