Development of evaluation system for measuring muscle metabolism

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The purpose of the present study is to observe muscle metabolism by means of newly developped measuremten system (NDMS) which consisted of NIRS,MMG and EMG apparatus. Using the NDMS the muscle oxugenation was estimated during various muscle contractions. For example, when the knee extensor muscle such as rectus femoris, vastus lateralis, vastus medialis and vastus intermedius were contracted isometrically during such long time as over 50 minutes, i.e.muscle fatigued, the transfer of activity among each muscle was observed, especially, activity of rectus femoris muscle increased when other muscle inactivated andvise versa. The muscle oxygenation in these muscle group were accompanied by the changes in these activation level. On the other hand, when isometric contraction (knee extension) was performed intermittently 50 times with rested 3 seconds EMG and MMG activities obtained from knee extensor muscle decreaed by 70% and 50% respectively. The order of activation level of MMG was RF<VL<VM.This differences of MMG has been considered to be due to differences of muscle fiber type composition in each muscle group. From these results it is suggested that muscle fatigue affect on muscle activation pattern and metabolism, especially rectus femoris muscle indicats specific responces compared to other knee extensors.group were accompanied by the changes in these activation level. On the other hand, when isometric contraction (knee extension) was performed intermittently 50 times with rested 3 seconds EMG and MMG activities obtained from knee extensor muscle decreaed by 70% and 50% respectively. The order of activation level of MMG was RF<VL<VM.This differences of MMG has been considered to be due to differences of muscle fiber type composition in each muscle group. From these results it is suggested that muscle fatigue affect on muscle activation pattern and metabolism, especially rectus femoris muscle indicats specific responces compared to other knee extensors.