Effect of repetitions on static and dynamic strength

Abstract

The objective of this study was to investigate the effect of repetitions on static and dynamic strength. The study is divided into two parts, the first part investigated static and dynamic strength during one, three and six repetitions per minute, and the second part of the study analyzed dynamic strength data collected using the Multiaxial Multipurpose Isokinetic Dynamometer. The study comprised of dynamic strength test data at three speeds of one, five and ten inch per second. Five male subjects participated in the first part of the study, and the results were analyzed by plotting a time series to observe the pattern of change in strength with repetitions. The results show a linear decrease in static and dynamic strength; the rate of decrease was the highest for static six repetitions per minute and the least during the dynamic one repetition per minute test. There was a decrease of 48.72% in strength for static six repetitions/minute routine and a decrease of 5.15% during dynamic one repetition per minute routine. Plot of Median Frequency (MDF) of EMG signals showed the highest rate of fatigue occurrence during static six repetition/minute and the least during dynamic one repetition/minute routine. The results of the second part of the study also show a linear decrease in dynamic strength for the three speeds. The highest percentage decrease in strength was 15.62% during one inch per second routine, and least decrease in strength was 8.7% during the ten inch per second pull routine. During the push cycle, the highest percentage decrease in strength was 18.56% during five inch/second routine and the least decrease was 8.28% during one inch/second. Another important fact is that all subjects were able to exert a maximum strength of 64.89 lb during five inch per second pull routine. This value was greater than the strength values exerted during one and ten inch per second push and pull routines. The MDF plot of the EMG signals showed the highest rate of fatigue occurred during five inch per second routine, and the least rate during one inch per second routine.