Differences of Thigh Muscle Activation During Various Squat Exercise on Stable and Unstable Surfaces

Abstract

PURPOSE: The purpose of this study was to compare thigh muscle activities and muscle co-activation when performing squats, wall squats, and Spanish squats on stable and unstable ground.METHODS: Twenty-two healthy male subjects (age: 22.50±2.70 years, height: 178.72±6.04 cm, mass: 76.50±6.80 kg, body mass index: 24.00±2.10 kg/m<sup>2</sup>, and Godin activity questionnaire: 56.30±24.10) voluntarily participated in the study. All of the participants performed three different squat exercises on the floor and the BOSU ball with an electromyograph attached to each participant’s quadriceps (rectus femoris, RF; vastus lateralis, VL; and vastus medialis, VM) and hamstrings (biceps femoris, BF; semitendinosus, ST; and semimembranosus, SM). Repeated measures of analysis of variance were utilized to compare muscle activity during the three squats exercises by floor type.RESULTS: RF (<i>p</i><.001, η<sup>2</sup>=.689), VL (<i>p</i><.001, η<sup>2</sup>=.622), and VM (<i>p</i>=.002, η<sup>2</sup>=.375) showed significant differences between exercises. Spanish squats yielded greater BF activity than did wall squats (<i>p</i>=.018, η<sup>2</sup>=.269). ST yielded greater muscle activity with the BOSU ball than on the floor (<i>p</i>=.018, η<sup>2</sup>=.269). Finally, there was a significant ground exercise interaction effect on the co-activation, showing greater muscle co-activation with Spanish squats on the BOSU ball compared to squats, squats on the BOSU ball, and wall squat on the BOSU ball.CONCLUSIONS: The findings of this study indicate that Spanish squats could be an effective exercise option for the facilitation of RF, VL, VM, and BF muscle activation. In particular, performing Spanish squats on an unstable surface could be useful for patients who need to improve their quadriceps muscle activation.