Influence of medial longitudinal arch flexibility on lower limb joint coupling coordination and gait impulse.

BACKGROUND

A causal link exists between structural differences in the foot and alterations in the lower limb biomechanics, which might predispose an individual to develop characteristic musculoskeletal disorders.

RESEARCH QUESTION

This study aimed to determine how the foot structural characteristics, as represented by the medial longitudinal arch flexibility, affect lower limb joint coupling coordination and anterior-posterior ground reaction impulses (GRIs) during walking and running.

METHODS

Following the calculation of arch height flexibility, a total of fifty-four physically active males were grouped and completed gait experiments to collect kinematic and kinetic data synchronously. Inter-joint coordination and variability were calculated from the angle-angle plots of knee-hip, ankle-knee, and metatarsophalangeal (MTP)-ankle couplings based on an optimized vector coding technique.

RESULTS

Our results indicate that coupling coordination of interest and its variability, as well as anterior-posterior GRIs, could potentially be influenced due to differences in arch height flexibility. Notably, the individuals with stiff arches exhibited significantly greater coordination variabilities during the early stance for both ankle-knee and MTP-ankle coordination yet significantly smaller for MTP-ankle coordination variabilities during the mid-stance phase. Furthermore, combining the statistical parametric mapping analysis results, the flexible arches experienced a greater proportion of GRIs in the anterior-posterior direction.

SIGNIFICANCE

In conclusion, these observations demonstrated that variations in arch flexibility led to differences in lower limb joint coordination variabilities and GRIs during gait. This fresh insight into inter-joint coordinative function may be useful for enhancing foot motion strategies based on arch structural characteristics.