It's family run night at the freehold New Jersey running club, where kids, two and older are racing with their parents.   

"Running is fun, running is for a lifetime, running is healthy," said Isabel Keeley, Director of New Jersey Running Club.  

As childhood obesity rates rise, parents are looking for ways to keep their little ones active. Like running, a sport that used to be reserved for teens and older - but as the numbers of young runners grow so do the injuries.

Jenny Westerhoff began running in her early tweens, eventually joining her high school cross country team. That's when the pain started.  

"After awhile, I could feel it in my knee cap, and I would always want to stop," said Jenny.     

The American College of Sports Medicine finds young female cross country runners have the highest rates of injuries, even over high school football players. That's because teenagers are still growing and prone to injury.   

"I see it in young girls that are in their puberty phase, that are starting to develop hips, have anatomic changes which can predispose them to having knee pain," said Dr. Wiemi Douoguih from Washington Hospital Center.

The same applies to little kids. Doctors warn that starting a child runner, too early can create shin splints, muscle pulls and tendonitis. They recommend no child run a race until they're in kindergarten.  

"There are a lot of activities that involve running, that are not just running that may be more fun for the kids," said Dr. Douoguih  

Llike soccer or basketball, the best way to avoid injuries is to make sure your child has the proper pair of shoes and consider getting a coach. Proper form is essential for keeping young runners injury-free.