Lower back injuries don't just happen to the overweight and middle-aged. They're the third most common type of injury suffered by young athletes, more common than even concussions, according to a new study. And over a third of them are serious enough to cause long-term problems.

Overtraining appears to be the single biggest culprit behind young athletes' back injuries. Children and teenagers are still growing. Their bodies are still growing, developing and can't take as much repetition, and therefore training, as an adult body can. When they try to, the result is usually an injury.

Athletes who specialized in one sport were the most likely to be injured.

Back injuries can occur because of a one-time hyperextension (overextension) of the back or from an accumulation of stress and strain over time. Insufficient strength of the abdominal and back extensor muscles may also play a role.

“If a young athlete has lower back pain for two weeks or longer, it is imperative that the athlete be evaluated by a sports medicine physician,” says Neeru Jayanthi, MD, sports physician at Loyola University Medical Center and study author.

“If a serious injury such as a stress fracture is not properly treated and does not heal properly, the athlete could be at risk for long-term back problems.”

The study reviewed the medical files of more than 1,200 athletes from Chicago and surrounding areas, aged 8-18, who had received sports physicals or treatment for injuries at Loyola University Medical Center or Lurie Children's Hospital of Chicago between 2010 and 2013. Fifteen percent of the injured children had lower back injuries. Only knee and ankle injuries were more common.

Athletes who specialized in one sport were the most likely to be injured. And those with back injuries tended to spend more time at sports, 12.7 hours weekly, than children with other injuries did (11.3 hours).

Jayanthi offers nine tips to reduce the risk of back and other injuries in young athletes. And since four involve not overdoing it, that seems to be the biggest key.

  • Don't specialize in one sport before late adolescence.
  • Don't spend more hours per week than your age playing sports.
  • Don't spend more than twice as much time playing organized sports as you spend in gym and unorganized play.
  • Don't play competitive sports year round. Take a break from competition for one to three months each year. The break(s) need not be taken all at once.
  • Take at least one day off per week from training in sports.
  • If there's pain in a high-risk area such as the lower back, elbow or shoulder, take one day off. If pain persists, take one week off.
  • If symptoms last longer than two weeks, get evaluated by a sports medicine physician.
  • In racket sports, form and strokes should be evaluated to make sure the back is not regularly extended by more than 20 degrees.
  • Enroll in a structured injury-prevention program taught by qualified professionals.

Athletes and their parents need to realize that a young body, no matter how athletically gifted, has its limits. Exceeding them is a surefire road to injury.

The findings from the study were presented at the American Academy of Pediatrics 2013 National Conference and Exhibition in Orlando on October 28.