EFFECT OF HIGH-SPEED RESISTANCE TRAINING ON MUSCLE CROSS-SECTIONAL AREA AND SPEED OF MOVEMENT

A conducted to determine 1) the effect of high-velocity movement in resistance training with a constant load on the velocity of movement after training and 2) the differences in the effect on muscle hypertrophy according to training velocity. Fourteen of the total subjects (male; n=10, female ; n=7) were placed in the experimental group and agreed to participate in 8 weeks of training sessions (4 times a week). Five of the 17 subjects were in control a group before the training session. Subjects performed elbow extension and flexion exercise using 50% of one repetition maximum (% 1 RM) load. The exercise session consisted of 6 sets of 10 repetitions and 30s of rest was taken between the sets. The subjects in the experimental group trained their arms using two different protocols ; one was high-velocity movement performed as rapidly as possible (Type R) , the other was low-velocity movement performed at a constant and slow velocity (Type S). Isokinetic torque in elbow flexion was measured at angular velocities of 60, 180, 300 deg/s, respectively , during elbow flexion performed under different constant loads of 0, 30, 50% 1 RM, and the muscle cross-sectional area (CSA) of the elbow flexor was determined before and after training . It was found that Type R did not increased isokinetic torque at 300 deg/s significantly after training. However, the increase in angular velocity of elbow flexion in Type R exercise tended to be higher than in Type S exercise . The increase in CSA [Type S; 11.2%, Type R ;14.2%] was significantly higher in Type R exercise (p<0.05). These results suggest that high-velocity movement with a constant load in resistance training might increase the angular velocity of movement in the same mode, but might not produce a change in isokinetic strength, which involves a different mode of muscle contraction . Muscle hypertrophy would be induced to a greater extent by high-velocity movement than by low-velocity movement in resistance training with a constant load. (Jpn. J. Phys. Fitness Sports Med. 1996, 45:345•`356)