Got baseball? Spending one’s youth playing catch is good for the bones, with benefits that last a lifetime.

Years of hurling balls boosted bone size, mass and strength in the throwing arms of current and former professional ballplayers, researchers report March 24 in the Proceedings of the National Academy of Sciences. Though bone mass withered away when players retired, some of the extra size and strength stuck around — even 50 years after the athletes last played ball.

“If you exercise when you’re young, it makes your bones bigger and stronger for life,” says study coauthor Stuart Warden, a bone physiologist at Indiana University in Indianapolis.

Scientists have known for years that childhood physical activity makes bones stronger. But no one knew just how long the benefit lasted or whether it fended off fractures and bone