EFFECT OF POSTURAL CHANGES ON REARFOOT KINEMATICS DURING GAIT

Purpose: Excessive rearfoot eversion during gait increases the risk of musculoskeletal dysfunction. This study examined the effect of postural changes on rearfoot kinematics during gait. Methods: Fifteen healthy men conducted gait trials under three postural conditions: neutral posture (NP), sway back posture (SBP) and forward leaning posture (FLP). An examiner visually assessed posture maintenance during trials based on a previous study. Kinematic data, including peak foot-ankle complex dorsiflexion, peak rearfoot eversion, and trunk-pelvis tilt angles, were collected using a three-dimensional motion capture system. Results: Trunk-pelvis tilt angles were significantly more posteriorly tilted in SBP (3.7[Formula: see text] and 6.3[Formula: see text]) and more anteriorly tilted in FLP (− 12.6[Formula: see text] and − 4.9[Formula: see text]) compared to NP (− 4.9[Formula: see text] and 3.3[Formula: see text]) ([Formula: see text] < 0.01), confirming appropriate postural control. The peak dorsiflexion angle of the foot-ankle complex significantly increased under the SBP (10.1[Formula: see text]) ([Formula: see text] < 0.01) compared to NP (8.5[Formula: see text]) and significantly decreased under the FLP (7.4[Formula: see text]) ([Formula: see text] < 0.05). Similarly, the peak rearfoot eversion angle significantly increased under the SBP (9.7[Formula: see text]) ([Formula: see text] < 0.05) and significantly decreased under the FLP (8.1[Formula: see text]) ([Formula: see text] < 0.05), compared to NP. Conclusions: Postural changes altered peak foot-ankle complex dorsiflexion during gait, corresponding with rearfoot eversion, which may increase under higher foot-ankle dorsiflexion demands.