Association between Height of the Forefoot Transverse Arch and Kinetics orKinematics of Ankle Joint during Gait

Objective: Most studies on arch biomechanics focus on medial longitudinal arch (MLA) its function; however, there are fewer studies on forefoot transverse arch (FTA) biomechanics its function is not understood. This study aimed at investigating function FTA on foot kinetics kinematics during gait.Methods: Nineteen healthy participants (10 men, 9 women) with a mean age 25.8 years were recruited. Each measurement was performed with participants’ dominant foot. For evaluating FTA, transverse arch index (TAI) was measured using ultrasonic diagnostic equipment, which represented relative height FTA. Measurements were performed in a two-stance condition: 90% weight bearing (90% WB), 10% weight bearing (10% WB). For evaluating MLA, arch height ratio (AHR) were measured with a ruler. A three-dimensional motion analysis system was used capture analyze foot kinetics kinematics. Participants were instructed walk barefoot along a 7 m walkway at regular walking pace (110 steps/minute). To examine function FTA, spearman’s correlation coefficients were calculated for non-parametric variables (TAI at 10% WB with foot kinetics and kinematics), examine relationship between MLA FTA, (TAI at 10% WB with AHR), examine flexibility of FTA, (the difference between TAI in 90% 10% WB with vertical ground reaction force (GRFV)in stance).Results: A significant positive correlation was observed between TAI max GRFV in terminal (r=0.50, P=0.03). There was no significant difference between TAI at 10% WB AHR, A significant negative correlation was observed between difference in TAI at 90% 10% WB and, max GRFV in terminal (r=-0.64, P=0.003).Conclusions: The present study showed that GRFV in terminal stance was positively correlated with the height FTA, that flexibility FTA has relative GRFV in terminal stance during gait. It is important to measure flexibility FTA as well as height FTA so as predict risk forefoot injury.