Neural Adaptation Analysis of Muscle Isometric Maximum Voluntary Contraction Resistance Training at Different Joint Angles / 医用生物力学

ABSTRACT

Objective To study the characteristics of neural adaptation for resistance training of maximum voluntary contraction (MVC) of muscles at different joint angles. Methods Thirty healthy male college students were randomly divided into 3 groups, and each group was subjected to MVC isometric contraction resistance training at elbow joint angles of 45°, 90°, and 135°. Surface electromyography (sEMG) signals of the biceps brachii were measured before and after training, and the root mean square (RMS) and median frequency (MF) of the sEMG signals were also analyzed. ResultsThere were significant differences in normalized RMS of sEMG for the biceps brachii before and after training at 45°, 90°, and 135° elbow joints. Comparison of the RMS between different angles after training showed that 45° was significantly different from 90° and 135°. There were no significant differences between 90° and 135°. After training, no significant differences were found in normalized MF at all angles. Conclusions The RMS of sEMG shows angle-specific changes, while the MF of sEMG does not have angle-specific changes. When the biceps brachii is at the middle and large elbow joint angles, the neural adaptation effect produced by isometric resistance training is better.