PurposeTo investigate the differences in foot kinematics during gait between adults with asymptomatic and symptomatic flatfoot.MethodsThe study included 10 participants (six males and four females, aged 25.7 ± 6.5 years) with symptomatic flatfoot and 10 participants (eight males and two females, aged 21.2 ± 1.0 years) with asymptomatic flatfoot. Multi-segment foot kinematics were captured during barefoot gait analysis using a 3D software. Angles were calculated for the calcaneus with respect to the shank (Sha-Cal), the midfoot with respect to the calcaneus (Cal-Mid), and the metatarsus with respect to the midfoot (Mid-Met) during the stance phase.ResultsSome differences were noted between medium-to-large effect sizes. The symptomatic group had a decreased Mid-Met dorsiflexion angle at the initial contact to 50% of the stance phase compared with the asymptomatic group. The symptomatic group also showed decreased Mid-Met abduction at initial contact, larger Sha-Cal eversion angles at 10% of the stance phase, and larger Cal-Mid eversion angles at 50% and 70% of the stance phase compared to the asymptomatic group. The symptomatic group also had a larger peak Sha-Cal eversion angle than the asymptomatic group.ConclusionAdults with symptomatic flatfoot exhibit significant differences in foot kinematics towards decreased forefoot dorsiflexion at initial contact to mid-stance, decreased forefoot abduction at initial contact, and increased rearfoot eversion during the stance phase compared with those with asymptomatic flatfoot during gait. Pain may impair intersegmental motion.