Significance of Bilateral Coactivation Ratio for Analysis of Neuromuscular Fatigue of Selected Knee Extensor Muscles during Isometric Contractions at 0o in Sportspersons

摘要

Muscle coactivation is the activation of two or more muscles simultaneously around a joint. Coactivation of knee muscles especially quadriceps is considered to be an important phenomenon for the stabilization of patellofemoral joint. The purpose of this study was to investigate the Coactivation ratio of selected knee extensor muscles as measure of neuromuscular fatigue in relation to gender, performance and side (right and left) of male (n1=19) and female (n2=8) during isometric contraction. The isometric contraction consisted of performing knee extension with an angle between 0o to 10o with a load of 30 repetition maximum (RM) on the CYBEX exerciser. The statistical analysis applied were ANOVA with post hoc analysis to determine the influence of fatigue in terms of gender, performance and side (right and left). The results showed significant decrease in the coactivation ratio of the selected muscles pair during isometric contraction with progression of fatigue (time). It also showed male dominance behavior over females in coactivation of Vastus Medialis (VM) and Vastus Lateralis (VL) muscles.. The results of this study would help to better understand the changes in activation strategies that can provide valuable information regarding the mechanisms that alter neuromuscular activity.