Evaluation of training efficacy for improving maximal voluntary contraction without noticeable hypertrophy

: The aim of the study was to estimate efficiency of the strength training protocol designed to improve maximal voluntary contraction without development of muscle hypertrophy. The principal difference between chosen training protocol and classical strength training was that the number of training movements during training session was increased to improve the motor skill, and rest periods between the training movements were increased as well to minimize damage of muscle fibers, which is one of the factors inducing muscle hypertrophy. Knee extensors of right leg in 11 physically active males were trained 4 times a week for 4 weeks. Evaluation of force-velocity characteristics with simultaneous recording of EMG-activity was performed in both trained and untrained legs immediately before, during and several times after the 4 wks training period. Before and after training the size and contractile properties ofipsi- and contralateral knee extensors were evaluated by MRI and twitch interpolation technique. Maximum strength gains after 4 week of training were about 17% in both trained and untrained legs and did not differ significantly from each other. A noticeable increase of EMG-activity during contraction was also found for both legs after 4-wks training period. The observed changes were not accompanied by any significant changes of muscle size, demonstrating the "neural" nature of the training effects.