関節固定による廃用性筋萎縮を自動運動で防止することを目的として，ラットを対象に実験的研究を行った。一側後肢足関節を底背屈中間位で，7日間にわたりギプス固定を実施した。固定期間中に1日2度ギプスを除去して1度に20分のトレッドミル歩行を行う群を運動群とし，1日2度ギプスの巻き替えのみを行う群を固定群とした。固定を行わない群をコントロール群とした。実験最終日に，ヒラメ筋の筋湿重量と筋張力を計測し，その後は組織学的検討を行った。筋湿重量と筋線維短径の結果から自動運動により廃用性筋萎縮の発生を防止できることが明らかとなったが，筋張力の維持は不十分であった。

We studied the effects of active exercise on preventing muscle atrophy secondary to joint immobilization in rats. A unilateral ankle joint was immobilized in the functional position with a cast for the duration of seven days. In the active exercise group, the casts were removed for a session of treadmill running (20 min.) twice a day. In the fi xation group, the casts were changed twice a day. In the control group, the cast fi xation was not done. On the last day, the wet weight and maximum tetanic tension of the soleus were measured. Subsequently, a histological examination was carried out. According to the results of the muscle wet weights and lengths of the muscle fi ber cross-section minor axes, disuse muscle atrophy was prevented in the active exercise group. But, the tetanic tension was decreased not only in the fi xation group, but also in the active exercise group.

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