In football, if the team on offense is in the “red zone,” it means they're inside the opponent's 20-yard line and moving toward a score.

How many times the offense gets into the red zone, and then how often they score from within that zone, is a measure of the team's efficiency.

On the school playground, getting in the zone is a smart way for kids to reach their goals of more physical activity and better classroom performance.

Researchers at the University of Missouri-Columbia have found that dividing playgrounds into activity zones caused a "significant increase in physical activity."

In a zoned playground, kids have many activity options, so there's something that suits every child.

For example, there's an area where kids can play dodgeball, another for jumping rope, one for basketball, hopscotch, and free play, such as climbing on a jungle gym or just running around.

(Free play is as important as organized activities: Studies show that it stimulates creativity and helps build social skills.)

Encourage your local school to adopt activity zones, and make sure playground supervisors leave their cellphones in their pockets.

According to the American Academy of Pediatrics and the Consumer Product Safety Commission, more than 200,000 children ages 14 and younger are treated in U.S. emergency rooms for playground-related injuries every year. They estimate that about 30 percent of those injuries could have been avoided if caregivers were not distracted.

When kids see that their caregiver is not paying attention, they're far more likely to engage in risky behavior.