engleski

Vertical jump height represents a body size independent measure of muscle power

In the present study we tested the hypothesis that the performance of rapid movements represents a body size independent index of muscle power. Physical education subjects (n = 159) were tested on various vertical jump and leg extensor strength tests. Both the jump height and average power were calculated from the ground reaction force during jumping. Principal component analysis (PCA) applied on all vertical jump measures, leg extensor strength tests and body size indices revealed a complex and inconsistent structure of the three extracted principal components were the jump height and muscle power loaded different components, while muscle strength and power partly overlapped. However, when the indices of muscle strength and power were normalized for body size using theoretical predictions of geometric similarity (i.e. divided by mass powered by the of 0.67), a simple and consistent structure of principle components appeared to be in line with the hypothesis. Specifically, the recorded height and muscle power calculated from the same jumps loaded the same components, separately for the jumps predominantly based on concentric and those based on a rapid stretch-shortening cycle of leg extensors. The third and fourth extracted principal components were loaded with the indices of the leg extensor strength and body size, respectively. If supported by future studies performed on other rapid movements, the finding that the performance of rapid movements assess the same physical ability as properly normalized tests of muscle power could be of exceptional importance for designing and interpreting the results of batteries of physical performance tests, as well as for understanding some basic principles of human movement performance.

body size; muscle power; jumping

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