High school athletes who focus on a single sport may be at increased risk for knee and hip injuries, a new study suggests.

"Make sure your children are getting breaks in competition," said study author David Bell, assistant professor in the Departments of Kinesiology and Orthopedics and Rehabilitation at the University of Wisconsin-Madison.

"There are so many great aspects to sports participation and we don't want this information to scare athletes or parents -- we just want them to be wise consumers and to participate as safely as possible," he said in a university news release.

The study included more than 300 athletes at two high schools, one large and one small. About 36 percent of the athletes had high levels of sports specialization. Nearly 29 percent had moderate specialization, and about 35 percent had low specialization, the researchers said.

The one-year study found that athletes from the smaller school were less likely to specialize than students from the larger school. Those in the high specialization group were more likely to report a history of overuse knee injuries than those in the other two groups. Athletes who trained in one sport for more than eight months during the study were more likely to have a history of knee and hip injuries, the researchers reported.

The study was published recently in The American Journal of Sports Medicine.

"Recommendations already exist to try and limit athletes' year-round exposure to sports," Bell noted. "Yet we don't know how well these recommendations are known to the average person.

"Our next step is to survey parents and athletes regarding their knowledge of sport participation recommendations, and also their attitudes toward sport specialization," he said.

More information

The American Academy of Pediatrics offers sports injury prevention tips.