Every day, millions of youths in the United States participate in sports activities, from soccer fields and snow-covered slopes to baseball diamonds and ice rinks.

It’s called playing, but sports activities are more than play. Participation in athletics improves physical fitness, coordination and self-discipline and gives children valuable opportunities to learn teamwork.

Sports activities can also result in injuries — some minor, some serious and some leading to lifelong medical problems.

Today’s kids are starting sports earlier and training longer and harder, often before they enter kindergarten. Many of them are suffering overuse injuries as a result.

Overuse injuries are a result from overtraining. Even 10 years ago it was popular to be a two- or three-sport athlete switching to a new sport each season. This seems to be a thing of the past, as the competition, access and seasons expand to be year-round. Now with competition starting at or before grade school, children are more times than not choosing one sport and sticking with it. This gives them a competitive edge as they develop their coordination, strength and reflexes for that sport. But too much of one sport can have its drawbacks. Orthopedic pediatric surgeons estimate that 30 percent to 50 percent of children’s sports injuries are now overuse injuries as opposed to acute traumatic injuries such as fractures, bruises and strains of the past.

Experts attribute this to more youths specializing in one sport at an early age and training year-round.

This specialization has come with a price. Playing different sports throughout the year is a form of cross-training that was extremely beneficial to a young body’s physical development. Playing multiple sports gives some muscles a chance to rest while others are being worked. Now those muscles are used nonstop and have no recovery time.

Training the same muscles year-round is believed to be the cause of the rise in overuse injuries in young athletes. The stress can cause young bodies to break down. When you stress the same body parts over and over, there’s a risk of injury.

Prevent overuse with conditioning, training

Most overuse injuries can be prevented with conditioning and training. Cross-training in moderation throughout the year helps prevent any one area of the body from becoming overworked and stressed and helps maintain overall fitness levels.

Children should be encouraged to participate in sports at a level consistent with their abilities. Pushing children beyond limits is discouraged, as is specialization in a single sport before adolescence.

Parents and coaches should be cautious when a young athlete has pain, and should not encourage a child to “play through” the pain.

The American College of Sports Medicine estimates that 50 percent of overuse injuries in children and adolescents are preventable. Pre-participation screening, required by most schools, should be encouraged for all children involved in organized athletics. This assesses health and can detect conditions that might limit participation or predispose an athlete to an injury.

Signs of excess

Because there are no guidelines for what constitutes overtraining, parents, athletes and coaches need to be aware of possible warning signs that athletes are overtraining which include:

• Excessive use of over-the-counter pain medications

• Changes in an athlete’s performance or techniques

• Psychosocial changes

Dr. Donald Pennington is an orthopedic surgeon at Samaritan Orthopaedics and Sports Medicine in Corvallis. He can be reached at (541) 768-4810.