Factors in Maximal Power Production and in Exercise Endurance Relative to Maximal Power.

摘要

The relationship of muscle fiber type and mass to maximal powe r production and the maintenance of power (endurance time to exhaustion) at 36, 55, and 73% of maximal power was investigated in 18 untrained but physically active male subjects. Power output was determined at constant velocity (60 RPM) on a high intensity cycle ergometer instrumented with force transducers and interfaced with a computer. Fat free mass was determined by hydro-static weighing, fat free thigh volume by water displacement and skinfold measurement, and percentage and area of type II fibers from biopsies of the vastus lateralis. Maximal power averaged 771 + or - 149 W with a range of 527-1125 W. No significant correlations were found among percentage of type II fibers, relative area of type II fibers, or fat free thigh volume and maximal power or endurance times to exhaustion at any percentage of maximal power. Weak but significant relationships were found for fat free mass with both maximal power (r=0.57) and endurance time at 73% of maximal power (r=0.47). These results show maximal power to be more dependent on factors related to body size than muscle fibers characteristics. Keywords: Anaerobic exercise, Skeletal muscle fiber morphology, Fat free thigh volume, Cycle ergometry strength physiology, Physical fitness. (AW)