Since these are fairly new problems, your parents and grandparents might not have all the answers—but we do!
Follow these 10 rules to keeping your kid active and you'll have a great head start at turning activity and fitness into life-long habits.
Rule 1: Don't Rely on Organized Sports1 of 11
Just because your kid is in T-ball doesn't mean that he's active enough. A new study in the Archives of Pediatrics & Adolescent Medicine found that less than 25 percent of student athletes receive the recommended 60 minutes of daily exercise.
Plus, the researchers found that the kids spent about 30 minutes of their practice sessions being completely inactive.
Coaches need to make sure everyone is participating in the game, so some children might have to wait their turns to head onto the field, say the scientists. They suggest that adults should take a more active role in the practice sessions, even if that means monitoring children with a pedometer.
America's fight against childhood obesity starts with parents.
Rule 2: Keep Play Fun2 of 11
Don't worry too much about the rules. "Making a game or activity too rigid is the best way to guarantee that a kid won't want to be active," says Men's Health FitsSchools advisor Jim Liston, C.S.C.S. "Your job is to facilitate play, not dictate it."
If your kid stops playing an organized game and start chasing a butterfly, just go with it. "As long as young kids are running, jumping, and having fun, they're improving their health and athletic ability."
Rule 3: Turn off the TV...3 of 11
If you want your kid to get off the couch once in a while, you have to do the same. Case in point: A 2010 study by British researchers found that 6-year-old girls were nearly 3.5 times more likely to watch more than four hours of television a day if their parents similarly stared at the tube for two to four hours a day.
As for boys, the scientists found that the little guys were about 10 times more likely to watch TV for four hours a day if their parents did as well.
Luckily, the solution is simple-turn off the tube. But what about "educational TV," you ask? Fact is, only one out of every eight shows for children are real learning opportunities.
Rule 4: ...Unless You're Playing Wii4 of 11
We're not saying that your child should start spending more time in the living room than the backyard, but kids can have a good workout by playing certain video games. Recently, the American Heart Association officially stated that Wii Fit Plus and Wii Sports Resort games are legitimate ways to stay active.
And a recent study in the journal Pediatrics found that kids (aged 10 to 13) who played Dance Dance Revolution had an exercise session that was comparable to walking at a moderate-intensity pace.
Rule 5: Never Reward Kids With Food5 of 11
It's no wonder childhood obesity is so prevalent: "We tell our children to eat healthy, but then we reward their good behavior with junk food," says Liston. No, there's nothing wrong with an occasional treat. But to consistently reinforce a kid with ice cream and candy for a job well done-such as finishing his homework-delivers the wrong message.
In fact, you should use caution in rewarding kids with any kind of food, including healthy fare. "This practice can teach them that it's good to eat even when they're not hungry," explains Liston. Instead, give them another kind of reward-like extra playtime outside.
Rule 6: Instruct by Showing, Not Telling6 of 11
Forget the phrase "Keep your eye on the ball." Why? Because the first time most a kid hears it, he (or she) has no idea what you're talking about. Focus on showing your child how to do what you want them to do and you'll be amazed at how quickly they'll begin mirroring your actions to a T.
Rule 7: Know When to Praise7 of 11
Kids aren't stupid. Say your son whiffs at three pitches in a row. The modern parent often says, "Good try." But that type of hollow praise doesn't console him, or help him the next time he steps up to the plate.
"Praise should be specific and authentic, as in, 'Good job juggling the ball 10 times. I see you've been practicing a lot. Your efforts have paid off,' " says Liston. "You should also mix instruction and encouragement when your child makes a mistake." Look for a teaching point, even on a strikeout. For instance, you might say, "Good eye on that second and third pitch. Keep swinging at pitches like those, and the hits will come."
Rule 8: Make a Play Date With Friends8 of 11
Remember the days of running around with the neighborhood kids from dawn until dusk? Wasn't that fun? Well, it's also an essential way to keep your kid in shape: UK researchers found that children who have an active, neighborhood playmate are two to three times more likely to be physically active themselves when compared to kids who don't live near a buddy.
Rule 9: But Don't Compare Your Kids With Others9 of 11
Kids develop the coordination to run, catch, and throw at different rates, says Liston. The trouble is, they're often expected to perform at certain levels based solely on their ages. As a result, a child whose development is slower than average may never have the opportunity to catch up with his peers.
"If a kid tries to catch a baseball on the run before he's able to catch a beach ball while standing still, he won't have the tools he needs to be successful, says Liston. Unfortunately, many parents and coaches think the solution is for the child to try harder, when the real secret is backing up to a simpler task that the kid can improve upon.
Rule 10: Give Them Your Support10 of 11
Encouraging your kids to participate in "vigorous" sports-like basketball and soccer-can cause your children to become more active, according to research in the journal Health Psychology. In the study, kids who received support from their parents were more likely to sign up for team sports (and less likely to spend their time sitting around) than the children who's parents didn't give them a push.
Obvious-and simple, right? Then what are you waiting for?