Low-frequency Isometric Training, 1-day of Training Every 2 Weeks, Increases Muscle Strength in Untrained Subjects

概要

論文の詳細を見る
The purpose of this study was to investigate the effects of low-frequency isometric training (1 day of training every 2 weeks) on muscle strength, which had been thought to have no effect. Fourteen male university students who had not experienced hard strength training were randomly assigned to train either 1 day per 2 weeks (2T group, n=7) or 1 day per 3 weeks (3T group, n=7). The 2T and 3T groups trained the knee extensors of the right leg by producing 3 sets of 5 seconds maximal isometric contraction per day for 8 weeks and 12 weeks, respectively. After 8 weeks of training, in the 2T group, maximal isometric torque in the trained leg significantly increased 15.0% (208.3±18.4Nm to 237.4±19.5Nm); iEMG of the m. rectus femoris significantly increased 30.7%; and the iEMG of the m. vastus lateralis increased 43.6% without any significant difference. On the other hand, there was no change in the cross-sectional area of the m. quadriceps femoris. The same measures in the untrained leg of the 2T group and in both legs of the 3T group were not changed after training. These results suggest that 1) low-frequency isometric training 1 day per 2 weeks increases muscle strength in untrained subjects and 2) the improvement in strength is mainly accounted for by neural factors.