Form and Function: Stronger Toes and Shorter Heels Associate With Better Gait Performance

The human foot's unique structure is believed to facilitate our adoption of habitual bipedal locomotion. The foot is particularly important in enabling economical forward propulsion through plantar intrinsic force output and ankle plantar flexor force transfer. An increased capacity for economical forward propulsion would enhance walking performance, that is, faster preferred walking speed (PWS) and improved walking endurance (WE). However, the association between the foot's unique features and walking performance remains unclear. This study investigated whether neuromechanical (flexor digitorum brevis muscle activity and thickness, toe flexor strength) and anthropometric (heel and toe length) foot features associated with PWS and WE (ie, 6-min walk test distance) in younger adults. Stronger toe flexors associated with greater WE (r = .641, P = .010), whereas shorter heels (ie, calcaneus length) associated with faster PWS (r = -.527, P = .044). Stronger toe flexors enhance WE by increasing net propulsion capacity, whereas shorter heels may enable optimal muscle-tendon operating conditions. These insights highlight potential targets for rehabilitation and assistive devices designed to improve walking performance in individuals with gait impairments.