Neuromuscular Adjustments of the Quadriceps Muscle After Eccentric Resistance and Concentric Resistance Training

Deficiency in the neural control of movement is associated with poor posture and skeletal muscle injuries. Exercise training is commonly reported as an intervention to improve neuromuscular activity. However, maximizing the effectiveness of exercise interventions for improving neural control of movement has been less investigated. The purpose of the current study was to examine improvement in neuromuscular activity (e.g., muscle fiber conduction velocity) and quadriceps function after eccentric resistance training versus concentric training.

A total of 24 men participated in this study and were randomly divided into eccentric training (n=12) and concentric training groups (n=12). Maximal voluntary isometric contraction (MIVC) of quadriceps, vertical jumping, and multichannel surface electromyography (EMG) signals were recorded before and 12 weeks after resistance eccentric and concentric training. Muscle fiber conduction velocity (MFCV) and root mean square (RMS) were computed using raw EMG signals.

The percentage increases in MVIC and vertical jumping after eccentric resistance training were significantly higher than those after concentric training (P<0.05). Likewise, eccentric exercise resulted in a higher increase in MFCV and RMS of EMG than concentric exercise (P<0.05).

A higher increase in neuromuscular activity and quadriceps performance observed after eccentric exercise may indicate that eccentric resistance training is more effective in improving neuromuscular activity and muscle function.