The vastus medialis obliquus muscle (VMO) performs an important role in the medial patellar stability . However , the recruitment of the lateral components, the vastus lateralis longus (VLL) and vastus laterallis oblique (VLO) is not established. The main purpose of this work was to investigate the electromyographic (EMG) activity of the VMO, VLL and VLO muscles of twenty one health volunteers (X= 23,3 ± DP 2,9), 10 female and eleven males, without clinical pain symptoms or osteomioarticular injuries EMG NICOLET VIKING II was used with eight channels (NICOLET Biomedical Instruments, and bipolar electrodes surface in order to record the electrical activity of VMO, VLL and VLO muscles during a isometric knee extension at 15º and 90º. The EMG data were normalized by maximum voluntary contraction (MIVC) of the knee flexion at 50º has shown that the VLL and VLO muscles demonstrated significant difference in recruitment pattern and they can be considered physiologically distinct. The VMO and VLO muscles performed synchronic and reciprocal role in the patellar stability and the VMO muscle performed higher activity compared with the VLL muscle in isometric knee extension at 90º.
Knee; Muscle; Electromyography
