Foot arch height affects the effect of BMI on gait and lower-limb joint kinematics

Foot arch structure contributes to walking in adults with obesity. However, little is known about the relationship between arch height and walking in these populations. The purpose of this study was to investigate if arch height affects gait characteristics among adults classified into three groups by body mass index (BMI). In this study, dynamic plantar pressure, spatiotemporal gait parameters, and lower-limb joint kinematics were collected from adults with normal weight (n=21), moderate obesity (n=18), and severe obesity (n=8) during walking at their preferred speed. Digital foot pressure data were used to compute a measure of arch height, the Chippaux-Smirak Index (CSI). Our results revealed that adults with higher BMI scores had lower arches than adults with lower BMI scores (p<0.01). Arch height was related to step width, double-limb support time, knee joint extension angle, and knee joint abduction angle (ps<0.01). Our results have implications for improving gait stability and increasing physical activity for obese populations via intervening in arch height.