Effect of shoe modifications on center of pressure and in-shoe plantar pressures

This study was conducted to determine the effect of footwear modification o n patients with neuromusculoskeletal disorders, Two analyses, the center of pressure and the in-shoe plantar pressures, were studied with the help of healthy volunteers so that the effect of shoe modifications could be assess ed. The ground force under the sole of the shoe was measured while the subj ects were walking, and the plantar pressure at the foot-insole interface an d its distribution were measured while the subjects were in both the standi ng and walking positions, wearing the trial shoes. The trial shoes had thre e different types of heels-standard heel, Thomas heel, and reverse Thomas h eel-and had three different locations for the rocker bar-just under the met atarsophalangeal joint, 1 cm behind the metatarsophalangeal joint, and 1 cm before the metatarsophalangeal joint. The shift change at the center of pr essure showed that the Thomas heel generally pushed the center of pressure more laterally and the reverse Thomas heel shifted it medially more than th e standard heel did. While the subjects were in a stable standing position wearing the Thomas heel shoes, the medial forefoot and the lateral heel reg ion's pressure showed significant reduction in the plantar pressure and the lateral forefoot and the medial heel showed a tendency to rise, compared w ith the standard heel condition. When the trial shoes' heels were changed t o the reverse thomas heel, the above changes tended to reverse. Tests at th e foot-insole interface showed that the different types of heels and the lo cation of the bar could change not: only the pressure distribution but also the duration of the plantar pressure under the lateral area that shifted t o the medial area when the subjects walked. This pressure measurement metho d was very useful for the design and evaluation of such footwear.