Anaerobic "sprint-interval" metabolic conditioning differs from aerobic in that exercise intensity is greater (supramaximal) and duration is shorter in the former; exercise modality may be identical, and is usually total-body in nature. Manipulation of the exercise:relief ratio should be based upon several criteria: competitive activity-inactivity profiles, bioenergetic kinetics and time courses of phosphagen repletion and lactate clearance during recovery. While there is discussion in the literature regarding manipulation of chronic training variables (especially exercise intensity, duration, volume, frequency, program progression and duration, concurrent "cross-training" compatibility and testing) and of the functional significance of such training in previously untrained subjects, data on athletic populations are scarce. However, it appears that sprint-interval training yields specific, positive physiological adaptations in the neuromusculature. Directions for future research should include the mechanisms and trainability of substrate repletion and metabolite clearance kinetics, concurrent strength-power and metabolic training compatibility and calcium metabolism.
(C) 1991 National Strength and Conditioning Association