Dr. Luis Lopes of the University of Minho in Braga, Portugal, said children who spend more than three-quarters of their time engaged in sedentary behavior, such as watching TV and sitting at computers, have up to nine times poorer motor coordination than their more active peers.
"It is very clear from our study that a high level of sedentary behavior is an independent predictor of low motor coordination, regardless of physical activity levels and other key factors," Lopes said in a statement. "High sedentary behavior had a significant impact on the children's motor coordination, with boys being more adversely affected than girls."
The study involved 110 girls and 103 boys ages 9-10. The children's sedentary behavior and physical activity were measured with accelerometers -- a device that quantifies movement counts and intensities -- over five consecutive days.
Motor coordination was evaluated with the Korperkoordination Test fur Kinder, which includes balance, jumping laterally, hopping on one leg over an obstacle and shifting platforms, Lopes said.
The study, published in the American Journal of Human Biology, found, on average, the children spent 75.6 percent of their time being sedentary -- girls who spent 77.3 percent or more of their time being sedentary were 4 to 5 times less likely to have normal motor coordination than more active girls.
However, boys who were sedentary for more than 76 percent of their time were between 5 to 9 times less likely to have good or normal motor coordination than their active peers.