Increased unilateral foot pronation affects lower limbs and pelvic biomechanics during walking

BACKGROUND: Increased unilateral foot pronation may cause biomechanical changes on the lower limbs during gait. We investigated the effects of increased unilateral foot pronation on the biomechanics of lower limbs and pelvis during gait. METHODS: Kinematic and kinetic data of 22 participants were collected while they walked wearing flat and laterally wedged sandals. Principal omponent analysis was used to compare differences between conditions. FINDINGS: Wearing the wedged sandal on the ipsilateral side increased ankle eversion moment (p<0.001; effect size=0.97); rearfoot eversion angle (p<0.001; effect size=0.76); shank internal rotation (p=0.009; effect size=0.53); increased and reduced knee internal rotation angle during early and late stance, respectively (p<0.001; effect size=0.89); increased femur internal rotation (p=0.005; effect size=0.90); reduced hip internal rotation moment during late stance (p=0.001; effect size=0.68); and increased pelvic ipsilateral drop (p=0.02; effect size=0.48) of the ipsilateral side. Wearing the wedged sandal on the contralateral side increased pelvic contralateral drop (p=0.001; effect size=0.63); hip adduction moment throughout stance (p=0.027; effect size=0.46); and increased and reduced the knee adduction moment in early and late stance, respectively (p<0.001; effect size=0.79). INTERPRETATION: The increased lower limb internal rotation caused by the wedged sandal reinforces the assumption that rearfoot eversion is coupled with shank internal rotation. The increased pelvic contralateral drop caused by the wedged sandal on the contralateral side may explain the increased hip and knee adduction moments on the ipsilateral side. Increased unilateral foot pronation causes biomechanical changes on both lower limbs that are associated with the occurrence of injuries.