Thesis

The power-velocity relationship of skeletal muscle during cycle ergometry

The objective was to determine the general shape of the curve describing the power-velocity relationship of skeletal muscle during cycle ergometry and determine the influence of muscle fiber type on mechanics of power production. 16 males volunteered and gave informed consent. A familiarization session was conducted in which subjects received training, and measurements (height, weight, 7-site skinfolds) were taken. The subject pool was divided into fast-twitch and slow-twitch subgroups based on a Thorstensson Fatigue Test. Other tests included max pedaling speed with no resistance, and power output and pedaling speed during a series of 12 6-s Wingate-types tests with resistances of 85 ? 195 gr/Kg LBM. Order of resistances was random, and 3 min of active recovery was allowed between tests. Testing was divided into two sessions so that subjects performed six power tests on separate days. Other variables were maximum power output, and relative pedaling velocity. Results showed that the FT subgroup produced greater Max RPM, but less Max Power than the ST subgroup. These differences were not statistically significant. The shape of the power-velocity curve was expected to be parabolic, but instead had two peaks. This pattern was in the curve constructed with data from all subjects and in the curves constructed with data from the subgroups. The peaks for ST occurred at 105 and 145 gr/Kg LBM and at 115 and 155 gr/Kg LBM for FT. It was concluded that in fit males, maximum power is produced at resistances ranging from 105 to 155 gr/Kg LBM, and that a higher percentage of FT fibers tends to produce Max Power at higher resistances.

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