Simultaneous activation of muscles across a joint can be defined as muscle co-contraction. Its purpose is to augment the ligament function in maintenance of joint stability, provide resistance to rotation at a joint, and equalize the pressure distribution at the articular surface. The purpose of this study was to investigate the Co-contraction of selected knee stabilizer muscles as a measure of neuromuscular fatigue in relation to gender, performance and side (left and right) of male (n1=32) and female (n2=18) during sustained squat posture (yogic posture). Squat Posture was performed at an angle of 135º-150º because strength of knee stabilizers (muscles) varies from angle to angle and 135º to 150º is prominent angle range having high consideration for the performance of numerous physical daily routine activities such as walking, running, cycling, stepping and driving including development of fundamental skills for different sports across all ages and sex. Vastus Medialis (VM) and Vastus Lateralis (VL) muscles from the Quadriceps group were the knee stabilizers chosen for recording the EMG simultaneously from both right and left legs as these muscles are considered important for stabilization and protection of patellofemoral joint. The statistical analysis applied were ANOVA with post hoc analysis to determine the influence of fatigue in terms of gender, performance and side (left and right). The results showed significant female dominance behavior over males in coactivation of VM and VL muscles along with bilateral Asymetricity during sustained squat posture. The results of this study would help in better understanding the changes in knee stabilizers activation strategies that can help the clinicians and trainers in planning, execution of rehabilitation related to patellofemoral joint injuries.