Muller, J., Engel, F., & Ferrauti, A. (2009). Children tolerate intensive intermittent exercise better than adults. A paper presented at the 14th Annual Congress of the European College of Sport Science, Oslo, Norway, June 24-27.

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"In the exercise science literature, a decreased capacity as well as a strongly reduced efficiency of the anaerobic metabolic pathway is described in children. The benefit of and value to health of anaerobic training are questioned explicitly. Therefore, the recommendations for endurance training with children at young ages are usually focused on aerobic activities. In contradiction to this, analyses of the self-chosen leisure time movement patterns show that children prefer intermittent, explosive, and intensive activities of a very short duration." [An hypothesis is that what children naturally select for activities is contrary to what conventional theory describes.]

This study investigated how children and adults tolerate short, intensive, and intermittent anaerobic demands. Trained children (Girls = 13; ~10.6 years; Boys = 9, ~9.7 years) and athletic trained adults (M = 14; F = 12) completed an identical intermittent sprint-running protocol on an indoor track followed by an active (slow jogging) 30-minute recovery. The protocol consisted of 10 maximum 5-second sprints with a 40-second rest in between. After each set of five sprints, the rest was increased to two minutes. Heart rate, rating of perceived exertion, and 15-m time within each sprint were recorded. As well, blood lactate concentration and blood pH were measured pre-exercise, after five and ten sprints, and during the post-exercise recovery.

Maximum blood lactate and ratings of perceived exertion were significantly lower in children than in adults. Blood pH remained significantly higher in children than in adults. At a similar sub-maximum lactate level (6 mmol/l), pH remained higher in children. During recovery, the half time to reach a physiological lactate concentration was significantly shorter in children than in adults. There was no significant difference in decrease of 15-m times in the sprints between children and adults. A significant main effect of gender was only found for the 15-m times within the sprints.

Implication. Anaerobic intermittent exercises can be considered in athletic training with pre-pubertal children without any risk of metabolic or psychological overload or harm. The striking pH stability and the quicker recovery of the children point to an overall better regulated acid-base balance, something that is not currently entertained in popular literature. Several recommendations in the exercise science literature with regard to children cannot be justified when the data of this study are considered.

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