Electromyographic activity and applied load during seated quadriceps exercises

Abstract

These findings suggest clinicians should consider biomechanical and resistance data when developing a strengthening program for the quadriceps muscle. Some seated quadriceps exercises may be more appropriate for certain rehabilitation goals than others.

Análise eletromiográfica do quadríceps durante a extensão do joelho em diferentes velocidades

“…By performing the test with V120, there was a significant increase of the level of myoelectrical activity of the parts of VMO, VML, VL, and RF muscles compared to the motion at angle speed of 60º/sec. Similarly to other studies, when comparing each muscle activation intensity at different test situations, the VMO selective activation could not be identified (7,9) . Those results suggest that the quadriceps may act as a muscle complex, in which the requirement of a stronger muscle activation is distributed among all its portions.…”

“…Those results suggest that the quadriceps may act as a muscle complex, in which the requirement of a stronger muscle activation is distributed among all its portions. Matheson et al (7) found a strong interaction among the RF, VL and VMO in different kinds of exercises for quadriceps strengthening. Tobin and Robinson (2) state that the VMO has an inherent ability to reach VL activity levels and this ability is lost in individuals with PFPS.…”

“…This contractile and non-contractile structures system allows for an appropriate stability of the patella. Any dysfunction on these structures results in an inappropriate dislocation of the patella from the femoral trochlea (3,7) . The balance on muscular activity between the VL and the VMO is seen as essential for an adequate arthrokinematic relationship between the patella and femoral trochlea (8) .…”

“…Due to the importance of the VMO for patellar stability, rehabilitation is focused on the specific strengthening of this muscle portion, associated to a reduced patellofemoral stress (1) . Some authors evaluate this specificity through the analysis of the VMO/VL ratio or through direct comparison of activation levels among those muscular portions (7,9) . Travnik et al (6) suggest the existence of higher concentrations of type-I fibers in VML and of type-IIb in the VMO.…”

“…The influence of the speed in performing knee extension on the levels of electromyographic activity of the quadriceps was little probed in literature. Matheson et al (7) suggest the possibility that, by addressing knee extension exercises in different angle speeds and resistance kinds, different levels of muscle activation are achieved for VMO over the VL.…”