Very intense exercise-training is extremely potent and time efficient

Very intense exercise-training is extremely potent and time efficient: a reminder -- Coyle 98 (6): 1983 -- Journal of Applied Physiology: "...All-out sprint training especially stresses recruitment and adaptation of type II (i.e., fast twitch) muscle fibers that are remarkably and equally responsive as type I (i.e., slow twitch) muscle fibers in their ability to increase mitochondrial enzyme activity to high absolute levels (4, 5, 7). In fact, the low-intensity aerobic exercise that is typically prescribed for endurance training or health is not very effective at increasing aerobic enzyme activity in type II muscle fibers, which comprise approximately one-half of the fibers within the thigh (vastus) and calf (gastrocnemius) muscle in most people (6). Thus low-intensity aerobic training is not a very effective or efficient method for maximizing aerobic adaptations in skeletal muscle because it generally does not recruit type II muscle fibers. The present report by Burgomaster et al. (2) provides a reminder of the effectiveness of sprint interval training, performed three times per week, and it demonstrates that large increases in aerobic enzyme activity and aerobic performance capacity previously measured after 7–8 wk (6) can occur after as little as 2 wk and only six sessions."

This is for those of you, who were wondering what type of cardio I perform and recommend...Note that type II muscle fibers are those, which we aim at to increase in size in the sport of bodybuilding!!
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