Former Ireland international Brian O'Driscoll has revealed that he underwent numerous neurological tests after retiring.
O'Driscoll, the second-most capped player of all time with 141, believed he was "slowing down" after hanging up his boots with Leinster and Ireland.
The tests ultimately were inconclusive, with O'Driscoll putting his concerns down to adjusting to life post-rugby after so many years at the top of the professional game.
“After I finished I felt as though I was slowing down a little bit," O'Driscoll told the Sunday Times.
"I just felt that my co-ordination wasn’t quite the same, so I went and got a load of neurological tests and scans just to be sure.
He added: "Excuse the pun, but I think it was in my head.
"When you are doing something for 15 years and when you stop for six months, of course your co-ordination is going to be down a fraction.
"So I had the tests and everything was fine.”