INFOGRAPHIC 16.5Influence of Exercise Intensity on Energy System UseRelative energy system contribution to total energy expenditure for any given duration of maximal intensity exercise (e.g., the point at 3 minutes assumes that someone ran as far as possible in that time). Even for very brief, high-intensity exercise, aerobic systems make some contribution to ATP production, however, as exercise duration increases, so does the contribution aerobic metabolism makes to total energy supply.