MUSCLE FIBERS DETERMINE WORK POTENTIAL

Esbjornsson, M., Sylven, C., Holm, J., & Jansson, E. (1993). Fast twitch fibers may predict anaerobic performance in both females and males. International Journal of Sports Medicine, 14, 257-263.

Males and females with similar training backgrounds were analyzed for anaerobic performance and muscle characteristics. Whether there was any gender difference in the characteristics was also determined.

Muscle biopsies and a 30 sec all out Wingate test on a bicycle ergometer were performed.

Males were higher than females in peak power (44%), mean power (48%), total lactate dehydrogenase activity (33%), and substrate of LD (38%). Anaerobic performance was directly related to the proportion of type II fibers. Females differed only in muscle volume.

Implication. Anaerobic performance is directly related to the quantity of fast-twitch fibers in muscles. The relationship is independent of gender while recognizing that females have less quantity of fibers. Adding further muscle qualities to a predictive equation does not increase the prediction of anaerobic performance.

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