What’s the difference between Type I (slow-twitch) and Type II (fast-twitch) muscle fibers?
There are many characteristic differences that exist between type I and type II muscle fibers. Five of these characteristic differences are: the contraction speed, with type I being slow and type II being fast; the endurance, with type I having a higher endurance and type II having a lower endurance; the force per cross-sectional are, with type I being low and type II being high; the intramuscular ATP stores, with type I having low stores and type II having higher stores; and finally the Myoglobin content, with type I being high and type II being lower. Muscles will always fire in the same sequence: type I, II, IIA, IIAB, IIB.
