Even though not all children will turn out to be football stars or champion sprinters, their athletic abilities are important not only for physical health, but predicting how physically active they will be as adults.
Phil Tomporowski, a professor of kinesiology at the University of Georgia, said factors such as a child's leg strength, motor control and balance can impact how well they perform at games and sports that they play with their peers. How they perform there can impact how confident they are in their physical abilities, and some studies have found that kind of confidence is important even in adulthood.
"Confidence plays a key role in whether children as adolescents or adults choose activities that are active and healthy promoting or more sedentary," Tomporowski said.
Though the study doesn't mention other sources of excessive screen time for kids, such as video and computer games, it does recommend that parents stick to the American Academy of Pediatrics' recommendations on TV viewing for kids: Children older than 2 should watch less than two hours of TV per day, and children younger than 2 shouldn't watch TV at all. Fitzpatrick suggested that TV time could be replaced by going outside, playing with blocks or other activities that are "developmentally enriching."
Briggs said the findings of this study suggest that parents who let their children watch TV may want to consider an additional tradeoff.
"If your child watches two hours of TV, maybe they should offset that with two hours of physical activity," she said.