Hsu, Chih-ChinChih-ChinHsuTsai, Wen-ChungWen-ChungTsaiChen, Carl Pai-ChuCarl Pai-ChuChenShau, Yio-WhaYio-WhaShauWang, Chung-LiChung-LiWangChen, Max Jin-LungMax Jin-LungChenKING-JEN CHANG2009-01-212018-06-292009-01-212018-06-292005http://ntur.lib.ntu.edu.tw//handle/246246/107073The plantar soft tissue properties under the metatarsal heads at different impact velocities in different age groups were measured. Each metatarsus of the left foot in healthy young adults (n = 9, 19 to 35 years old) and in healthy older persons (n = 10, 42 to 72 years old) was examined in vivo using a self-constructed loading-unloading device at low, medium and high impact status; the impact velocities of the device were about 2.5, 5 and 10 cm/s, respectively. The device comprised a 5- to 12-MHz linear-array ultrasound transducer, a miniature load cell and a fixation frame. From low to high impact status, the elastic modulus (E) in young adults significantly increased from about 300 kPa to about 500 kPa. However, the E in the older group did not show this trend. From low to high impact status, the energy dissipation ratio (EDR) of the metatarsus significantly increased from about 30% to about 60% in the young group and significantly increased from about 40% to about 70% in the older group. Most of the metatarsus in the older subjects had significantly greater E and EDR than those in the younger persons. ? 2005 World Federation for Ultrasound in Medicine & Biology.application/pdf310424 bytesapplication/pdfen-US[SDGs]SDG3Aging of materials; Biomechanics; Cells; Elastic moduli; Energy dissipation; Health care; Ultrasonic transducers; Aging; Impact velocity; Metatarsus; Ultrasonography; Tissue; adult; aged; aging; article; biomechanics; female; foot; forefoot; human; human experiment; male; metatarsal bone; normal human; priority journal; soft tissue; ultrasound; velocity; weight bearing; young modulus; Adult; Aged; Aging; Body Mass Index; Connective Tissue; Elasticity; Female; Foot; Humans; Male; Metatarsus; Middle Aged; Stress, Mechanical10.1016/j.ultrasmedbio.2005.05.0092-s2.0-26444480183WOS:000232618500016http://ntur.lib.ntu.edu.tw/bitstream/246246/107073/1/10.pdf