Abstract des Autors

A study was conducted to investigate muscle fatigue during isometric contraction of the indicis proprius using EMG analysis. The subjects were 8 healthymen (ranging in age from 19 to 42 years). Plummets (ranging from 300 g to 600 g) were placed on the distal knuckle of the index finger to create loads on the indicis proprius muscle. EMG was recorded until the plummet dropped, and the total time required was divided into 10 equal parts. In each part, the EMG record for the first 1000 ms was picked out. Then the mean power frequency (MePF) and median power frequency (MdPF) of the power spectrum were calculated. The results were as follows: 1) Both MePF and MdPF showed shifts to lower frequency bands. 2) Integrated values of the EMG power spectrum increased with time. 3) The time courses of the MePF and MdPF in each EMG sample for the 8 subjects were determined by the 3-point moving average method. A break-point was observed in each MePF and MdPF diagram. It was considered that two-break points observed int he time courses of the EMG record were valid as an objective index of local muscle fatigue. Verf.-Referat