Wang, C.-L.C.-L.WangHsu, T.-C.T.-C.HsuShau, Y.-W.Y.-W.ShauJENG-YI SHIEHYIO-WHA SHAU2020-04-072020-04-0719990736-0266https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033197577&doi=10.1002%2fjor.1100170513&partnerID=40&md5=d8266c064ee06b39f3ddd64c8588c83fhttps://scholars.lib.ntu.edu.tw/handle/123456789/483243The sole under the metatarsal heads functions as a shock absorber during walking and running. The mechanical properties of the sole provide the primary defense against the development of metatarsalgia and foot ulceration. However, limited information about these properties has been documented. In this study, we used ultrasonography to evaluate the mechanical properties, including unloaded thickness, compressibility index, elastic modulus, and energy dissipation ratio, of the sole in 20 healthy subjects. The unloaded thickness decreased progressively from the first to the fifth metatarsal heads, with values of 1.50, 1.36, 1.25, 1.14, and 1.04 cm. The sole under the first metatarsal head had the greatest values for the compressibility index and elastic modulus (55.9% and 1.39 kg/cm2), and the sole under the third metatarsal head had the smallest values (50.8% and 1.23 kg/cm2). The sole under the fifth metatarsal head had the greatest energy dissipation ratio (33.7%), followed by that under the third, second, first, and fourth metatarsal heads. Multivariate adjusted linear regression showed that the unloaded thickness, compressibility index, and elastic modulus values increased significantly with age and body weight (p<0.05) and that the energy dissipation ratio increased significantly with body weight (p<0.05).The sole under the metatarsal heads functions as a shock absorber during walking and running. The mechanical properties of the sole provide the primary defense against the development of metatarsalgia and foot ulceration. However, limited information about these properties has been documented. In this study, we used ultrasonography to evaluate the mechanical properties, including unloaded thickness, compressibility index, elastic modulus, and energy dissipation ratio, of the sole in 20 healthy subjects. The unloaded thickness decreased progressively from the first to the fifth metatarsal heads, with values of 1.50, 1.36, 1.25, 1.14, and 1.04 cm. The sole under the first metatarsal head had the greatest values for the compressibility index and elastic modulus (55.9% and 1.39 kg/cm2), and the sole under the third metatarsal head had the smallest values (50.8% and 1.23 kg/cm2). The sole under the fifth metatarsal head had the greatest energy dissipation ratio (33.7%), followed by that under the third, second, first, and fourth metatarsal heads. Multivariate adjusted linear regression showed that the unloaded thickness, compressibility index, and elastic modulus values increased significantly with age and body weight (p < 0.05) and that the energy dissipation ratio increased significantly with body weight (p < 0.05).[SDGs]SDG3Compressibility of solids; Elastic moduli; Energy dissipation; Ultrasonic applications; Compressibility index; Ultrasonography; Musculoskeletal system; adult; article; body mass; body weight; controlled study; echography; female; human; human experiment; male; mechanics; metatarsal bone; priority journal; young modulusjournal article10.1002/jor.1100170513105694802-s2.0-0033197577