抄録
Force plates and treadmills are commonly used to measure the ground reaction force (GRF) and center of pressure (COP) of walking. However, the location and condition of measurement are confined when using force plates and treadmills. To address this issue, we have developed a wearable insole-type force sensor for estimating GRF. In this study, we conducted COP measurements using the insole-type force sensor. The insole-type force sensor is equipped with an array of thin-film force sensors. The arrangement of thin-film force sensors is determined according to the subject's plantar pressure distribution while in a static and upright position, captured on pressure-sensitive paper. To measure plantar pressure changes in the longitudinal direction, sensors are placed in two-by-two fashion on the heel, metacarpophalangeal joint, and big toe areas. In addition, five sensors are placed for measuring changes in the horizontal direction. The total number of sensors used is smaller than that used in similar insole-type sensor. COP were estimated in five male subjects (age: 22.6 ± 1.5 years). Each subject wore the insole-type force sensor on the left foot. The measurements were made with the subject was standing on one leg or walking on the force plate. The COP trajectory calculated from the thin-film force sensor output was corrected for the inherent trajectory of the force plate using multiple regression analysis. In all subjects, the measured and estimated COP trajectories were within 10mm of each other after correction. The insole-type sensor allows easy measurement of COP while walking naturally.
