ELECTROMYOGRAPHIC ACTIVITY OF THE VASTUS MEDIALIS OBLIQUE AND VASTUS LATERALIS LONGUS MM. DURING OPEN AND CLOSED KINETIC CHAIN EXERCISES

Abstract

OBJECTIVES: The purpose of this study was to analyze the electromyographic activity of the Vastus Medialis Oblique (VMO) and Vastus Lateralis Longus (VLL) muscles during knee extension in Open Kinetic Chain Exercise, using a ‘knee extension table’, and in Closed Kinetic Chain Exercise, using a Horizontal Leg-Press (VITALLY). METHODS: The electromyographic activity of the VMO and VLL muscles was measured in 12 subjects between 18 and 23 years old (x=21.9 e SD=1.16), without prior hip, knee, and ankle pathologies, during Maximal Isometric Contraction (MCI) at 90º flexion of hip and knee. A 16-Channel EMG System (CAD 12/36 - 60 K - LINX) and differential surface electrodes (DELSYS) were used to obtain the data. The signal was recorded in Root Mean Square (RMS) and expressed in microvolts. The data analysis was performed through Student’s t-test at a 5% level of significance. RESULTS: The results showed that the electromyographic activity of the VMO muscle was significantly greater than that of the VLL muscle during Open and Closed Kinetic Chain Exercises. CONCLUSIONS: The data of this study, within the experimental conditions used, suggest that the VMO muscle can recover functionally by MCI at 90º flexion of hip and knee during Open Kinetic Chain Exercise, using an ‘extension table’, and also in Closed Kinetic Chain Exercise, using a Horizontal Leg-Press. This research was conducted in accordance with the National Council of Health (Resolution 196/96).