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This is a story about successful kids (especially boys), common sense, and research.

Most of us spend hours each day sitting at work. Science says it's killing us, and we have developed all kinds of fads to combat it—from standing desks to smartphone alerts to get us up and moving.

Armed with that knowledge, however, what do we force our kids to do each day at school? Sit still, for six or eight hours.

Now researchers say that mistake leads us into a three-pronged, perfect storm of problems:

1. We overprotect kids, trying to keep them safe from all physical dangers—which ultimately increases their likelihood of real health issues.

2. We inhibit children's academic growth (especially among boys), because the lack of physical activity makes it harder for them to concentrate.

3. When they fail to conform quietly to this low-energy paradigm, we over-diagnose or even punish kids for reacting the way they're naturally built to react.

Start With the Boys

News flash: Most boys are rambunctious. Often they seem like they're in a constant state of motion: running, jumping, fighting, playing, getting hurt—maybe getting upset—and getting right back into the physical action.

Except at school, where they're required to sit still for long periods of time. (And when they fail to stay still, how are they punished? Often by being forced to skip recess—and thus they sit still longer.)

It's not just an American issue. Researchers at the University of Eastern Finland recently tried to document whether boys actually achieve less in school when they're restricted from running around and being physically active.

They studied 153 kids, aged 6 to 8, and tracked how much physical activity and sedentary time they had during the day. Sure enough, according to a report by Belinda Luscombe in Time, the less "moderate to vigorous physical activity" the boys had each day, the harder it was for them to develop good reading skills:

The more time kids ... spent sitting and the less time they spent being physically active, the fewer gains they made in reading in the two following years. [It] also had a negative impact on their ability to do math.

The results didn't apply to girls. I know that sounds sexist; the researchers offered a few possible explanations. Maybe there simply are physiological differences—or maybe the girls were just as eager to move around as the boys, but they were better able to set aside that disappointment and concentrate.

And for that reason, other researchers say, girls are rewarded more than boys in the classroom.

"Girl behavior is the gold standard in schools," says psychologist Michael Thompson. "Boys are treated like defective girls."

A Dystopian, Scaredy-Cat World

It's not just about less academic achievement, however. Many observers and researchers now say limited physical activity leads to real physical and mental harm in kids—even in the short term, before they've grown up.

Angela Hanscom, a pediatric occupational therapist, interviewed young kids to ask them what recess and play are like in the second decade of the 21st century. Their descriptions sound like a dystopian vision of a scaredy-cat future:

"We have monkey bars, but we aren't allowed to go upside down on them. They think we are going to hurt ourselves. I think I'm old enough to try going upside down."

"We have woods, but can't go anywhere near them. It's too dangerous."

"When it snows, we can't touch it with our foot, or we have to stand by the teacher for the rest of recess."

Restricting kids' movement like this leads them to increased anger and frustration, less ability to regulate emotions, and higher aggressiveness during the limited times they are allowed to play, Hanscom writes. "Elementary children need at least three hours of active free play a day to maintain good health and wellness. Currently, they are only getting a fraction."

Expanding the Definition

You probably know that ADHD diagnoses in kids are more likely now than they were in years past, but you might not realize that the number of diagnoses is still rising—and at an alarming rate.

In 2003, for example, it was diagnosed in about 7.8 percent of kids, but that rose to 9.5 percent in 2007 and 11 percent in 2011. That's a 40 percent increase in eight years.

Why? For one thing, we've changed the definition of ADHD to make it more expansive. Many critics argue it's also because of the pharmaceutical industry, since the leading treatment for ADHD is use of the prescription drug Ritalin.

And Hanscom, in a separate article, says it's also because we're forcing kids to sit still longer—and they're simply reacting as nature intended.

"Recess times have shortened due to increasing educational demands, and children rarely play outdoors," she writes. "Lets face it: Children are not nearly moving enough, and it is really starting to become a problem."

Misaligned Incentives

Of course, these are complicated issues. Nobody wants kids to fail or develop health problems. But given the trends in science and research, why won't more schools at least experiment with including more recess and physical activity in their schedule?

The most commonly cited explanations are both simple and frustrating. Last year, for example, the New Jersey state legislature passed a law requiring public schools to include at least 20 minutes of recess each day—but the governor vetoed it, calling it a "stupid" idea.

Another big adversary is standardized testing, because the time required to prepare for and take tests has to come from somewhere. ("When we have standardized testing, we don't get recess," said one of the students Hansom interviewed. "The teachers give us chewing gum to help us concentrate on those days.")

There is also simple inertia. It's much easier to control a classroom in which the kids have to sit quietly than one where you allow for a little bit of managed chaos. Nobody judges teachers by whether they gave kids enough recess during the day.

And as long as we have overly protective helicopter parents, there will always be fear of liability issues. My free e-book, How to Raise Successful Kids, has more insights and advice on parenting.

Play Around a Bit

There are a few signs of hope. An elementary school in Texas began working four recess periods per day for each child into its schedule, for example. That was a big enough story to make the national news.

Result? Students are "less fidgety and more focused," one teacher said. They "listen more attentively, follow directions, and try to solve problems on their own instead of coming to the teacher to fix everything."

But this approach is the exception to the rule. Until schools figure out how to incorporate lots of movement and play into their schedules, it will be up to parents to compensate.

So set a good example with your own physical activity, and maybe side with your son (or daughter) if he or she gets in trouble for moving too much at school.

Hanscom reminds us of the stakes: "In order for children to learn, they need to be able to pay attention. In order for them to pay attention, we need to let them move."