Investigating the Effects of Eccentric and Concentric Resistance Training on Action Potential Conduction Velocity of Quadriceps Muscle Fibers

The purpose of present study was investigating the effects of 8 weeks eccentric and concentric resistance training on Action potential conduction velocity of quadriceps muscle fibers.

30 male inactive subjects (age: 22.3±2.1 years; weight 71.3±8.6 kg and height: 1.76±0.1 m) were recruited for this controlled laboratory study. Subjects were randomly divided into two groups: the eccentric training group (No=15) and the concentric training group (No=15).  The maximal voluntary contraction (MVC) of quadriceps muscles and surface electromyography signals were recorded before and after 8 weeks of resistance concentric and eccentric training with 80% of 1RM. The multifactorial variance and Tukey Post hoc tests were used for data analysis.  

The results showed that MVC of knee extension after eccentric resistance training and concentric resistance training significantly increased (P=0.001). Also the increase in the mean power frequency and Action potential conduction velocity of muscle fibers after eccentric resistance training was significantly more than the increase after concentric resistance training (P<0.05).

The higher increase in maximum voluntary contraction of knee extension is associated with increasing the frequency of moderate strength and Action potential conduction velocity of muscle fibers after eccentric resistance training indicates better adaptation and recruitment of fast-twitch muscle fibers to eccentric resistance training.