Electrical activity of the vastus medialis oblique and vastus lateralis longus muscles during isometric and isotonic exercises

Abstract

The purpose of this work was to evaluate if the vastus medialis oblique (VMO) muscle had greater electrical activity than the vastus lateralis longus (VLL) muscle during exercises of maximal resistence isometric contraction (MRIC) and maximal resistence isotonic contraction (MRIsotC) performed in Leg-Press (VITALLY). The electrical activity of the VMO and VLL muscles was investigate in 12 adult volunteers no sedentary (X= 21.9; SD= 1.16), without prior hip, knee and ankle pathologies, using a 16-channel Electromyographic System and program of Data Aquisition (Digital Analogue Conversor - CAD 12/36 - 60K - AqDados 4.6 - LYNX Tecnologia Eletrônica Ltda) and differential surface electrodes (DELSYS Inc.). The electromyographic records were measured by root mean square (RMS), in |J,V, and normalized as percentage of maximal voluntary isometric contraction (MVIC) of knee extension obtained in a flexion-extension table. The statistical analysis employed was the Wilcoxon test at 5% level of significance. The results showed that there was no difference between the electrical activity of the VMO and VLL muscles for both exercises studied (MRIC p=0.872; MRIsotC p=0.855). The data of this research, within the experimental conditions used, suggest that the VMO muscle can't be selectively recovered in relation to the VLL muscle by exercises of MRIC and MRIsotC.