Determinants of Postural Balance during a Deep Squat: Focusing on Lower Limb/Trunk Muscle Activity in Addition to Ankle Flexibility

Abstract

[Purpose] To clarify the rate of being able to perform deep squats and the relationships between body sway during a deep squat and the joint range of motion/muscle activity. [Participants and Methods] The deep squat test was conducted for 20 healthy university students. In those who were able to perform deep squats, the ankle dorsiflexion angle and lower limb/trunk muscle activity were measured to analyze the correlations between these values and body sway during a deep squat. [Results] The numbers of students who were able and unable to perform deep squats were 16 and 4, respectively. Through multiple regression analysis, the ankle dorsiflexion angle and activities of the tibialis anterior/rectus abdominis during a deep squat were identified as variables explaining body sway in this position. [Conclusion] It was shown that a certain rate of university students are unable to perform deep squats, supporting the results of previous studies. In addition to the ankle dorsiflexion range of motion, the muscle functions of the tibialis anterior and rectus abdominis were suggested to determine postural balance during a deep squat.