For safety, let kids set the pace
Of course, kids aren’t always going to want to run, and parents should use common sense when deciding how hard to push their aspiring athletes.

“Some days my son would rather play Wii, so we let him play Wii,” Dr. Halstead says. “But then we make sure we go out and run tomorrow instead.”

In fact, running every day probably isn’t the best way to train. For young, developing bodies, encouraging activities that work different muscle groups—whether it’s playing softball or basketball, bike riding, or swimming once or twice a week—is important as well.

Parents also should watch for signs of exhaustion and dehydration, especially during hot summer months, and should always take a child’s pain seriously: Stress fractures and overuse injuries can occur, and ignoring them will only make them worse.

The most important thing is letting kids set their own pace and giving them the support they need, rather than expecting them to adhere to an adult’s training schedule, Goodrow says.

“Some parents tell me they want their kid to train for a half marathon with them because they don’t want to give up their training time, and that’s just not responsible,” says Goodrow. “The worst thing I’ve seen is the kid who can’t keep up with the parent during a race and the parents are disgusted, or the parents who leave their kid behind before the kid is ready to be left alone.”

Get your family involved
If you’re looking to get your children more involved in fitness—whether you’re already a runner or not—there are no shortage of organizations and events to get you started. Active.com has information on family and kids’ races all over the country, and even a page for the active toddler.

IronKids.com lists children’s triathlons, which are usually offered in three different distances for three different age groups, 6 to 15. Triathlons, as daunting as they sound, can actually be a very safe choice for children in as long as they’re well organized and appropriate lengths (two concerns voiced by a recent New York Times article): Because you have to practice for three separate sports, there’s built-in cross-training and less worry about overuse injuries.

If you’re already signed up for a 5K or 10K race, talk to event organizers to make sure the event will be kid-friendly and that there are no time limits or age restrictions. And if you’re training for a half marathon or marathon, see if there’s a shorter fun run being held the same weekend that your son or daughter can train for at the same time.

For ideas about how to make running fun for kids, visit PECentral.org or CarolGoodrow.com. Goodrow has authored and illustrated several books and a 2010 calendar for children about the joy of running.

The best way to get children excited about running is to set a good example yourself, by showing them how good it makes you feel. By emphasizing fitness and family time over distance, speed, and competition, you can help your kids develop a healthy habit that can last a lifetime.