最大筋力と疲労

抄録

The maximum strength of the thumb adductor was produced by voluntary contraction with maximum effort and electric stimulation. The electric stimulation was applied through the electrodes attached on the skin of the upper arm near the elbow joint over the ulnar nerve trunk. For the maximum strength of the adductor muscle of the finger, rectangular current with the intensity of 50 to 60volt, the duration of 5msec and the frequency of 50cps was applied for 0.5 to 1.0 second. To measure the muscular strength of the thumb adductor, an isometric finger ergograph with strain gauge was used. The hand and four fingers except the thumb of the subject was fixed with plaster on the table. To measure the work output of the thumb finger, an isotonic finger ergograph against the load was used. The results are as follows: 1) The maximum strength induced by electric stimulation is always higher than by maximum voluntary effort. The average of the 5 subjects was 16.3±1.2kg (M±S.D.)in the former, and 12.8±1.4kg in the latter corresponding to 80 per cent of the former. 2) After the subject gave up his work on the ergometer by voluntary effort, the electric stimulation could add the number of contractions to some extent. The number of contractions in one subject was 93 by voluntary effort and the addition number of contractions was 25 by electric stimulation. 3) After the training on the finger ergometer using the load of 1/3 of the maximum strength for 9 to 12 weeks, both the number of contractions induced by voulltary effort as well as by electric stimulation was increased significantly to the same extent.