Analysis of quadriceps muscle activation at different squat angles using maximum voluntary isometric contraction (MVIC): A pilot study

¹ Department of Physiotherapy, Universitas Muhammadiyah Surakarta, Indonesia.
² Department of Physiotherapy, STIKES Bakti Utama Pati, Indonesia.

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The quadriceps muscles play a crucial role in active knee joint stabilization, particularly during functional activities such as squatting. Squat angle variations may influence muscle activation levels. This study aimed to analyze differences in activation of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) during squat variations using the Maximum Voluntary Isometric Contraction (MVIC) parameter. This pilot study used an Experimental Single Group design involving 12 male futsal athletes from Universitas Muhammadiyah Surakarta (aged 19–22 years, normal BMI, normal Q-angle). Muscle activation was measured with surface electromyography (sEMG) at squat angles of 120°, 90°, and 60°, each repeated three times. Data analysis included the Shapiro-Wilk test for normality and Repeated Measures ANOVA for inter-angle differences. Result showed that the highest activation at 120° was observed in VL (98.73 µV), at 90° in VM (133.42 µV), and at 60° also in VM (176.80 µV). Repeated Measures ANOVA revealed significant differences across all squat angles (p<0.05). Squat angle variation influences quadriceps muscle activation. VM showed dominant activation at 90° and 60°, whereas VL was dominant at 120°. These findings may guide the design of targeted quadriceps strengthening programs based on knee joint angle.