Abstract

The purpose of this study was to investigate muscle oxygenation during intense dynamic knee extension exercise, after a classification into four groups based on the relative merit of one repetition maximum (1RM) and the total number of repetitions loaded at 90%, 70% and 50% of 1RM (Ntotal). Thirty six male university undergraduate and graduate students with experience in various sports participated in the study. Subjects performed knee extension exercise at 1RM and a number of repetitions loaded at 90%, 70% and 50% of 1RM. Subjects were divided into four groups based on the results of 1RM and Ntotal (SN group : 1RM-high / Ntotal-high, Sn group : 1RM-high / Ntotall-low, sN group : 1RM-low / Ntotal-high, sn group : 1RM-low / Ntotal-low). Muscle oxygenation on the vastus lateralis muscle was measured during the repetition exercises. The minimum value and rate of decrease at onset of repetition exercise (4-9 seconds after the start of exercise) were calculated to estimate muscle oxygenation. The major findings were: (1) The relative merit of 1RM and number of repetitions at relative intensity affected the muscle oxygenation during repetition exercise. (2) A significant negative correlation between Ntotal and rate of decrease of muscle oxygenation was observed with loads at 70% and 50% 1RM, but not at 90% 1RM. These results suggest that it is important to focus on the improvement of aerobic capacityin resistance training to increase the number of repetitions at relative intensity. Verf.-Referat