足と足首の臨床研究

抽象的な

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

Tomofumi Matsushita, Yuto Tashiro, Yusuke Suzuki, Seishiro Tasaka, Keisuke Matsubara, Mirei Kawagoe, Yuki Yokota, Takuya Sonoda, Yasuaki Nakayama, Takahiko Fukumoto, Tomoki Aoyama

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