A definitive measure for assessing the energy contribution of anaerobic pathways during exhaustive exercise remains inconclusive. The accumulated oxygen deficit (AOD) has been used in several studies to estimate energy contribution. The underlying assumptions of the AOD measure have been criticized for underestimating the true contribution of anaerobic metabolism in high intensity exercise. Indeed, the AOD measure has been the subject of much controversy. Several of the physiological exercise responses of children may lead to an even greater underestimation of the anaerobic energy contribution to high intensity exercise in children than adults when AOD measures are calculated.