작업형태 및 최대 수의적 수축에 따른 등척성 근지구력에 관한 연구

Abstract

This study was performed to investigate the isometric endurance time as percentages of maximum voluntary contraction. Electromyogram(EMG) and Borg's CR-I0 value were measured by push-pull-up-down tasks for 10 healthy males. The normalized EMG value and the MPF(mean power frequency) were used to estimate the muscle recruitment pattern and the development of muscle fatigue. The subjects exerted and maintained 5 levels of %MVC(maximum voluntary contraction) in 90oshoulder flexion/ 180oelbow extension at sitting posture. The up-task showed the lower endurance time and higher Borg's CR-I0 value than the other task types. Comparing Rohmert's curve with the endurance time of task types. Rohmert's curve overestimated the endurance time of up-task and underestimated the endurance time of push-pull-down tasks. The normalized EMG value showed that muscles recruitment patterns were different from task types. The 4 muscles(biceps brachii muscle, tricep brachii muscle. middle deltoid muscle. trapezius muscle) recruitment patterns of up-task were higher than those of other tasks. The MPF value decreased with the endurance time, and the shift of MPF at up-task was larger than that of the other task types.