ST LOUIS — Steve Stahle, primary care sports medicine physician at U.S. Center for Sports Medicine in Kirkwood, Mo., said that in addition to the typical musculoskeletal injuries, children are also susceptible to growth plate injuries. The growth plate is the area of growing tissue near the end of long bones in children and adolescents.

The femur in the thigh and the humerus in the upper arm are two examples and each one has a growth plate at both ends of the bone. Those plates determine the future length and shape of the mature bone.

"You can strengthen your muscles, but you can't strengthen your growth plate," Stahle said. An overdeveloped muscle will pull on the slower growing, soft-tissue plates, increasing the risk of injury.

"Kids think they need to be training every day, when it's often better for them to take a few days off," Stahle said. "But it's hard to convince them of that and sometimes their parents, too."

He often tells them they might have the best 12-year-old pitcher in the history of Missouri but that if he injures that growth plate, his arm will stay 12 years old, while everyone else's is advancing.

"This is a growth plate. This is how he'll get bigger. And this is what we have to protect," Stahle said. "Kids are constantly told, 'Work hard and you'll get recognized. You play more, you get more exposure.' And they know they have to train hard to make it to the elite level. So a lot of times their parents don't even have to tell them that."