General, Lady TT, if an athlete stays very fit, enjoys the sport, and has burning desire to excel, they can play into their 40's. It's been proven many times, even in some of the world's toughest sports.
Darrell Green - Washington's Hall of Fame cornerback, kickoff & punt returns, one of the fastest football players to play in the NFL:
Green catches the quick Tony Dorsett
17 years later, Darrell Green still the fastest man on the team at 40 years old.
Respectfully,
masterclass
I know. I'm not worried about Rafa. His career has already been amazing. If he quits tomorrow I'd have enjoyed the last ten years. I expect/ed a lull in his career. It's only human.
Rafa will be fine, and if not, it'll still be fine with me.