Arch‐support induced changes in foot‐ankle coordination in young males with flatfoot during unplanned gait termination

Abstract

Objective: The efficacy of arch orthoses in posture adjustment and joint coordination improvement during steady‐state gait is well documented; however, the biomechanical changes of gait sub‐tasks caused by arch support (AS), especially during gait termination, are poorly understood. Hence, this study aimed to investigate how the acute arch‐supporting intervention affects foot–ankle coordination and coordination variability (CV) in individuals with flatfoot during unplanned gait termination (UGT). Methods: Twenty‐five male patients with flatfoot were selected as subjects participated in this AS manipulation study. A motion capture system was used for the collection of the metatarsophalangeal joint (MPJ) and ankle kinematics during UGT. MPJ‐Ankle coordination and CV were quantified using an optimized vector coding technique during the three sub‐phases of UGT. A paired‐sample t‐test from the one‐dimensional statistical parametric mapping of one‐dimensional was applied to examine the data significance. Results: Significant differences for the joint kinematics between non‐arch‐support (NAS) and AS were exhibited only in the MPJ transverse plane during the middle and later periods of UGT (p = 0.04–0.026). Frontal plane MPJ‐ankle coordination under AS during stimulus delay significantly decreased from 177.16 ± 27.41° to 157.75 ± 32.54° compared with under NAS (p = 0.026); however, the coordination pattern had not changed. Moreover, no significant difference was found in the coupling angle variability between NAS and AS in three planes during sub‐phases of UGT (all p > 0.5). Conclusions: The detailed intrinsic characteristic of AS induced acute changes in lower extremity segment coordination in patients with mild flatfoot has been recorded. This dataset on foot‐ankle coordination characteristics during UGT is essential for explaining foot function and injury prediction concerning AS manipulation. Further studies are expected to reflect lower limb inter-joint coordination during gait termination through the long‐term effects of AS orthoses.