Gene Expression of MyF5 and MyoG Genes of Eccentric and Concentric Resistance Activity in the Vastus Lateralis Muscle of Healthy Individuals

This study was mainly aimed at investigating gene expression of MyF5 and MyoG genes of eccentric and concentric resistance activity in the vastus lateralis muscle of healthy individuals. Ten healthy men were randomly assigned to two groups of concentric and eccentric contractions of five. Isokinetic contraction protocols included eccentric and concentric knee extension with a maximum power and angular velocity of 60 degrees per second. The torque set for each subject was considered the same in both protocols in order to match the load, and the reciprocating speed was 60 degrees per second. At the beginning and end of the activity, extensive biopsy was performed to examine the expression of MyF5 and MyoG genes. Results revealed that intra-group changes of MyF5 after one session of exercise were significant in eccentric (p = 0.001) and non-significant in concentric (p = 0.069) group. Moreover, inter-group changes showed no difference between the two group (p = 0.371). Besides, intra-group MyoG changes after one session of exercise were significant in the eccentric group (p = 0.001) and concentric group (p = 0.001). Furthermore, inter-group changes showed no difference between the two groups (p = 0.681). Overall, the present study showed that a session of eccentric and concentric activity leads to changes in the factors involved in skeletal muscle strength and hypertrophy. In addition, these changes in aggregate eccentric contraction are more than concentric.
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