Electromyographic Activities of the Vastus Medialis Oblique and Vastus Lateralis Oblique During Sustained Contraction After Eccentric Exercise

Document Type : Original Article

Abstract

We tested the electromyography (EMG) activities of the oblique and longus parts of the vastus medialis and 
vastus lateralis muscles before, 24 and 48 h after eccentric exercise. Surface electromyographic signals were 
recorded from the oblique and longus parts of the VMO and VLO muscles of the right quadriceps muscle of 10
healthy men during sustained contraction of 50% MVC, before, 24 and 48h after eccentric exercise. The 
eccentric exercise was performed with a KinCom Isokinetic Dynamometer (Chattanooga, TN) and comprised
four bouts of 25 maximum voluntary concentric/ eccentric knee extension contractions at a speed of 60 deg/s. 
Average rectified value (ARV) was estimated from the EMG signals for epochs of 1s, and were averaged over 
intervals of 10% of the time to task failure. Results: Maximal voluntary force and time to task failure were 
reduced (p < 0.001) following eccentric exercise. ARV reduced over sustained contraction for both VMO and 
VLO muscles (p < 0.05). ARV rat of reduction over time for VMO was greater than VLO muscle (p < 0.05).
The results indicate a greater effect of eccentric exercise on VMO than on VLO muscle.

Keywords

• Eccentric exercise
• quadriceps
• sustained contraction
• electromyography

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