Horizontal and Declined Squats in Healthy Individuals: A Study of Kinematic and Muscle Patterns

Abstract

Squats are frequently incorporated in physiotherapy programmes and performed in different ways. Accordingly, muscle and kinematic patterns also differ. The objective was to compare the kinematics and EMG patterns of the major muscles of knee and ankle joints during different squat exercises on horizontal (HP) and 25° decline (DP) boards. Seventeen healthy individuals performed squats on HP and DP with bilateral support and restriction of trunk movements in the sagittal plane. The knee and ankle angular displacements in the sagittal plane and the EMG activities of the major muscles of the lower limb in four subphases of movement were recorded and analyzed. For the descending phase of the HP squats, the angular excursion, as well as the initial and final positions, was smaller for the knee (P<0.05) but larger for the ankle (P=0.01). For the ascending phase of the HP squats, the initial and final positions were larger for the ankle (P<0.02) and the final position was smaller for the knee (P=0.05). All muscles remained activated and showed similarity between the tasks (P>0.44), except for the tibialis anterior in both squat exercises (P<0.03). The HP and DP squats produced different kinematics (knee and ankle joints) but did not modify the EMG strategy for both movement phases.