White Muscle Versus Red Muscle Fitness


One of the most important factors of an athlete’s genetic giftedness in strength and aerobic sports is the predominance of fast (white) or slow (red) muscle fibers. It is the structure of muscle fibers and their quantity in certain skeletal muscle groups that determines the strength or endurance of a sportsman. White muscle fibers are fibers that contain a small amount of myoglobin and mitochondria. Therefore, such muscle fibers consume a small amount of O2 and their color is white (Reid). White muscle fibers are responsible for physical strength, but only for a short period, and they are very susceptible to hypertrophy.


While muscle fibers contract very fast and provide energy for a short period. Elite sprinters, bodybuilders, and powerlifters have a large proportion of white muscle fibers in their bodies, a fact that allows them to get good results over short distances or in limited-time settings (Reid). If training is actively aimed at increasing overall muscular endurance, for example, marathon running, long–distance swimming, and other aerobic sports – there is an active increase in the number of red muscle fibers.


Red muscle fibers are called red because of the large number of blood vessels that run through them. They contract more slowly than white fibers and are responsible for endurance (Reid). The strength of red muscle fibers is limited by the number of myofibrils, and the duration of their work by the number of mitochondria, respectively. Red muscle fibers are not susceptible to hypertrophy, which is why marathon runners have a low percentage of muscle mass, despite the highest endurance of their muscles.


Reid, A. (n.d.) White muscle vs. red muscle fitness. Azcentral. Web.