The Association Between Foot Morphology and Foot Loading During Gait.

The perceived association between foot type and injury risk has inspired the development of many foot typing methods. The purpose of this study was to determine how well different foot typing methods explained variations in regional foot loading in asymptomatic adults during gait, while considering age, sex, and walking speed as covariates. Six methods were used to determine foot type in 92 asymptomatic adults. An insole pressure sensor system measured peak force and force-time integral during treadmill walking at a self-selected pace. The foot was divided into nine regions and the association between foot type and foot loading was analyzed using generalized estimating equations (GEE) while accounting for the covariates. Over an average of 250 steps per individual, the results demonstrated variability in the association between regional foot loading and foot type. Specifically, Arch Index and X-Ray Arch Type correlated with hindfoot and midfoot loading, while Foot Posture Index correlated with medial midfoot, forefoot, and toe loading. Calcaneal Pitch and Meary's Angle correlated with medial hindfoot, midfoot, and forefoot loading, while Varus/valgus angle correlated with loading in the forefoot and toes. The location and direction of associations were generally similar for Calcaneal Pitch, Meary's Angle, and X-Ray Arch Type, and opposite of Arch Index. The analyses demonstrated that walking speed, age, and sex were all important factors that affected the relationship between plantar loading and foot type. Specific foot type methods correlate better with loading in specific foot regions, potentially making them better to evaluate injury risk in those regions.