皮膚冷刺激下での低負荷筋力トレーニングが筋厚および筋力に及ぼす影響

Effects of Low-intensity Resistance Training with Skin Cooling on Muscle Thickness and Muscle Strength

要旨　筋力トレーニングは，筋力低下や筋萎縮の処方として用いられる手技である．先行研究において，皮膚冷刺激下での低負荷筋力トレーニングでは，神経適応により筋力が増加することが報告されている．しかし，皮膚冷刺激下での低負荷筋力トレーニングが筋厚に及ぼす影響は不明である．本研究の目的は，上腕三頭筋を対象に，皮膚冷刺激下での低負荷筋力トレーニングが筋力および筋厚に与える影響を明らかにすることである．対象は，12名の健常若年男性の両腕とし，無作為に皮膚冷刺激下での低負荷筋力トレーニングを行う側と低負荷筋力トレーニングのみを行う側に群分けを行った．筋力トレーニングは1RMの50％の重量を用いて，週3回8週間の介入を行った．筋力トレーニング介入前後に1RMと上腕三頭筋の筋厚を測定した．その結果，有意な交互作用は認められなかったが，皮膚冷刺激の有無に関係なく，両介入側ともに8週間の介入後に有意な1RMおよび筋厚の増加が認められた．この結果より，皮膚冷却による筋力トレーニングとの相乗効果は認められないことが明らかになった．

Abstract　Resistance training is a treatment for muscle weakness and muscle atrophy. Although previous studies reported that muscle strength increased via changes in neural adaptation after low-intensity resistance training with skin cooling (SC), the effects of the training on both muscle strength and muscle thickness were unclear. Therefore, this study investigated the effect of low-intensity training of the triceps brachii with SC on muscle strength and muscle thickness. Volunteers were 12 healthy men, with one arm randomly assigned to SC and the other to control groups. Elbow extension exercises were performed for 8 weeks, and 1 repetition maximum (RM) and muscle thickness of triceps brachii were measured before and after training. Resistance exercise was performed thrice a week using a dumbbell adjusted to 50％ of 1 RM for both the groups. The SC side used an ice bag secured to the triceps brachii during training. There were no significant interaction effects of 1 RM and muscle thickness of triceps brachii；however, both variables significantly increased after training in both the SC and control groups. Muscle strength and muscle thickness increased after the 8-week training program with SC. No significant differences were observed between the groups.