title: Effects of aging on the plantar soft tissue properties under the metatarsal heads at different impact velocities.
abstract: The 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.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: Chih-Chin
authors.initials: CC
authors.lastname: Hsu
authors.forename: Wen-Chung
authors.initials: WC
authors.lastname: Tsai
authors.forename: Carl Pai-Chu
authors.initials: CP
authors.lastname: Chen
authors.forename: Yio-Wha
authors.initials: YW
authors.lastname: Shau
authors.forename: Chung-Li
authors.initials: CL
authors.lastname: Wang
authors.forename: Max Jin-Lung
authors.initials: MJ
authors.lastname: Chen
authors.forename: King-Jen
authors.initials: KJ
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D003238:Connective Tissue / Q000000981:diagnostic imaging* / Q000502:physiology*; D004548:Elasticity; D005260:Female; D005528:Foot / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D008297:Male; D008684:Metatarsus; D008875:Middle Aged; D013314:Stress, Mechanical; D014463:Ultrasonography