It's 9 p.m. ...Kids In Bed Yet?

TAMPA, Fla. (KFSN) -- Just 20 minutes. That's all the extra sleep your kids may need to focus better at school. But parents also need to keep after-school activities in check.

Leah and Natalie Greenacre love cheerleading, but on top of other activities, homework and a never-ending morning routine, their mom called a timeout.

Dena Greenacre said, "They were much harder to get up, much crankier, and I wasn't sure why until I realized that they weren't getting enough sleep."

The American Academy of Pediatrics says nearly nine out of 10 kids go to bed after 9 P.M., which is too late. Experts say kids need around 10 hours every night, and when they don't, watch out.

Kathleen Armstrong, PhD, director of pediatric psychology at the University of South Florida said, "Many children will fall asleep in class, they're harder for parents to get them up in the morning. They're irritable, many of the children have short attention spans when they're not getting enough sleep, they may cry more easily. And they certainly can't focus on their work."

Catching more Z's often leads to more A's. Adding those 20 extra minutes of sleep can mean better grades in school. To do this, parents need to learn how to set limits on screen time, as well as after-school activities.

"I do think we over-schedule kids today. Kids, like adults, need to have down time every day where they can just play and relax," said Doctor Armstrong.

For the Greenacre family, the most popular cheer is spelled S-L-E-E-P.

Dena said, "After we quit we just kind of went back to our normal schedule that I feel is what they need to stay on track at school, stay healthy."

And we can't forget about our four legged children. Puppies need about 18 to 19 hours of sleep, while kittens need 13 to 16 hours a day.