Author(s): ISHIGURO, K., SAKAI, H., MATSUSHITA, K., NAKAYAMA, T., SHE, J., Institution: TOKYO UNIVERSITY OF TECHNOLOGY, Country: JAPAN, Abstract-ID: 569

INTRODUCTION:
Geta, often referred to as Japanese wooden clogs, are a uniquely Japanese type of footwear that have no parallel in the world. Geta are basically a wooden board called a ‘tooth’ that stands vertically to the ground with another wooden board placed horizontally over it with a toe strap attached. Typical geta have two-teeth but there are also single-tooth geta. Although geta are rarely used in modern day-to-day life, they are worn when dressing in kimono (traditional Japanese clothing) on special occasions. There are very few examples of kinematic studies using single-tooth geta, and there is little kinematic knowledge about how geta affect humans and whether they are useful in physical exercise.
METHODS:
Nine healthy males participated in this study. Their mean (standard deviation) age, height, and weight were 23.2 (2.3) years, 166.4 (7.2) cm, and 58.2 (6.6) kg, respectively. Prior to measurements, the purpose and procedure of this study were explained in detail, and informed written consent was obtained from all subjects. The subjects went barefoot and wore single-tooth and two-teeth geta. Before measurements were taken, subjects were allowed to practice walking with each pair of geta to achieve a comfortable gait. A VICON system and synchronized electromyography were used to capture three-dimensional movements. VICON data were recorded while subjects walked, from the time of heel contact to the completion of the walking cycle. Data were recorded throughout the right stance phase of the walking cycle. We defined the stance phase of the walking cycle, before and after the partial pressure of foot floor reaction, as the ‘braking phase’. The latter phase was defined as the ‘acceleration phase’. Statistical analyses were conducted using one-factor ANOVA and the Tukey-Kramer correction test.
RESULTS:
There were significant differences in the peak values of the floor reaction forces for vertical forces. The vertical component was significantly higher for barefoot and two-teeth geta than for single-tooth geta. In terms of the peak values of joint moments, the plantar flexion moment of the ankle joint increased significantly more in single-tooth geta than in barefoot and two-teeth geta. The dorsiflexion moment increased significantly more in barefoot and two-teeth geta than in the one-tooth geta. Muscle activity of the erector spinae muscles in single-tooth geta was significantly higher than in bare feet (p<0.05).
CONCLUSION:
When wearing single-tooth geta, the heel rocker function advocated by Jacquelin Perry could not be performed due to the shape of the footwear, so impact was absorbed by the plantar dorsiflexion movement of the ankle joint and the exertion of the plantar flexion moment while shortening the braking period. Based on these findings, single-tooth geta are considered to be relatively high-load footwear because they require a flexible ankle joint strategy.