The problem today is not that most children get too much exercise; instead most of them get too little. Obesity rates in children, especially those living in the United States, are rapidly rising. Many kids do not have the opportunity to play a sport or participate in any sort of physical activity, structured or unstructured.  And, some children, when given the choice, choose to spend their free time engaging in more sedentary activities anyway. Unfortunately, it seems that children who develop poor nutritional and exercise habits will most likely carry those habits into adulthood.

A study in 2002 was conducted on twelve sixth-graders. The twelve kids actually trained to walk a marathon. The purpose of the study was to assess their body composition and aerobic capacity after training for twelve weeks. The twelve kids walked four or five days every week for twelve weeks at about fifty percent of their individual maximal heart rates. Six other sixth-graders were controls for this study and they did not participate in the marathon walking program. Instead, they went about their normal lives.

Under adult supervision, the twelve kids started out by walking about ten miles per week and gradually increased their walking mileage to just over the marathon distance (twenty-seven miles). On each training day, the kids increased their walking mileage by about a quarter of a mile.  Both the participants and the control kids received pre-study and post-study fitness assessments. The assessments included skinfold measurements, height, weight, and maximal oxygen consumption. All the kids were also responsible for keep a three-day eating journal.

After the kids completed the study, the researchers examined their post-study fitness results, comparing them with the pre-study fitness results. The experimental group decreased the sum of their skinfold measurements more so than the control group. However, there was little to no change in the maximal oxygen consumption numbers for both groups. Since walking does not typically demand a large increase in oxygen consumption, those results are not surprising. However, a decrease in the skinfold measurement numbers does indicate some body fat loss. Walking burns about one hundred calories per miles. So, by the end of the study, the kids were burning about twenty-seven hundred calories per walking session. For that reason, it is beneficial for children to engage in regular physical activity, even if it is relatively undemanding.

Volpe, S.L., Rife, F.N., Melanson, E.L., Merritt, A., Witek, J., & Freedson, P.S. (2002). Physiological Changes in Sixth Graders who Trained to Walk the Boston Marathon. Journal of Sports Science & Medicine, 1, 128-135.