The effect of heel height variations on selected muscles activity and joint angle during squat exercise

The purpose of this study was to examine the effect of heel height variations on selected muscles activity (with emphasize on co-contraction) and joint angle during squat exercise. Joint range of motion and electromyographic activity from medial gastrocnemius, tibialis anterior, rectus femoris, vastus medialis, vastus laterlis, biceps femoris, semitendinosus and erector spinae muscles of ten active males were recorded while performed squat exercise at 0, 2, 3 and 4 cm of heel height conditions. A reduction activity was observed for tibialis anterior muscle while heel height, but there was no significant differences for the other muscles. There was a lower general co-contraction of the ankle joint muscles at 3 cm heel height condition that could minimize the perturbing effects of external loads on ankle during squat exercise. Therefore, performing squat exercise at 3 cm height condition could be recommended as a suitable position for both rehabilitation and sport applications purposes,