American Journal of Human Biology
The study, involving Portuguese children, found that physical activity alone was not enough to overcome the negative effect of sedentary behaviour on basic motor coordination skills such as walking, throwing or catching, which are considered the building blocks of more complex movements.
"Childhood is a critical time for the development of motor coordination skills which are essential for health and well-being," said lead author Dr Luis Lopes, from the University of Minho. "We know that sedentary lifestyles have a negative effect on these skills and are associated with decreased fitness, lower self-esteem, decreased academic achievement and increased obesity."
Dr Lopes' team studied 110 girls and 103 boys aged nine to ten from 13 urban elementary schools. The children's sedentary behaviour and physical activity were objectively measured with accelerometers (a small device that children attach to their waist that quantifies movement counts and intensities) over five consecutive days. Motor coordination was evaluated with the KTK test (Körperkoordination Test für Kinder), which includes balance, jumping laterally, hopping on one leg over an obstacle and shifting platforms.
The tests were supplemented with a questionnaire for parents to assess health variables, before the authors compiled the results into three models to calculate odd ratios for predicting motor coordination. These were adjusted for physical activity, accelerometer wear time, waist to height ratio and home variables.