Training intensely for just one sport can be dangerous for young, growing bodies, according to a new study.

In all, Dr. Neeru Jayanthi of Loyola University Medical Center in Chicago examined more than 1,200 athletes between the ages of 8 and 18 who either had undergone a sports physical or been treated for injuries between 2010 and 2013.

What he found was that of 850 injuries, 550 were the result of overuse and included over 130 cases of serious stress fractures, damage to ligaments, cartilage and underlying bone, among other things.

For this reason, Jayanthi said in a news release that parents "should be cautious about intense specialization in one sport before and during adolescence," recommending that young athletes limit the hours per week they spend on a particular sport to their age. In other words, an 11-year-old shouldn't spend more than 11 hours a week playing baseball or whatever sport it may that the child is engaged in.

Doing so, Jayanthi and colleagues found, can reduce the chance of injury by as much as 70 percent.

As Dan Gould, director of the Institute of Study of Youth Sports at Michigan State University, told ABC News, the drive for kids to perform well comes with the territory of increasing pressure to outperform peers.

"It's not bad for a kid to start recreational sport at four, but specializing? We are seeing more 'Little League pitching elbow' from repeated exposure," he said, adding that he has seen a lot of pressure placed on kids to do year-round sports, possibly in the hopes of achieving a scholarship one day.

In his report, Jayanthi encouraged parents to leave time for kids to pursue unorganized free play and avoid specializing in a sport before late adolescence. 

"Parents should consider enrolling their children in multiple sports," Jayanthi said.