To be included in the review, the studies had to have involved children younger than 16, lasted for at least four weeks, and reported objectively measured levels of physical fitness, like wearing motion sensors that tracked how much they moved, not just during the exercise classes but throughout the rest of the day. The studies included an American program in which elementary school-age students were led through a 90-minute session of vigorous running and playing after school, three times a week. Another program involved Scottish preschool youngsters and 30 minutes of moderate physical playtime during school hours, three times a week.
In each case, the investigators had expected that the programs would increase the children's overall daily physical activity.
That didn't happen, as the review's authors found when they carefully parsed outcomes. The American students, for instance, increased their overall daily physical activity by about five minutes per day. But only during the first few weeks of the program; by the end, their overall daily physical activity had returned to about where it had been before the program began. The wee Scottish participants actually became less physically active over all on the days when they had the 30-minute play sessions.
The review authors found similar results for the rest of the studies that they perused. In general, well-designed, well-implemented and obviously very well-meaning physical activity interventions, including ones lasting for up to 90 minutes, added at best about four minutes of additional walking or running to most youngsters' overall daily physical activity levels.
The programs "just didn't work," at least in terms of getting young people to move more, said Brad Metcalf, a research fellow and medical statistician at Peninsula College, who led the review.
Parents might want to consider incorporating more active time into home life, such as these yoga moves designed for families by Parents.com.
Image: Red tricycle, via Shutterstock