Effects of aging on the plantar soft tissue properties under the metatarsal heads at different impact velocities.
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.
Hsu
Chih-Chin
CC
Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taipei, Taiwan.
Tsai
Wen-Chung
WC
Chen
Carl Pai-Chu
CP
Shau
Yio-Wha
YW
Wang
Chung-Li
CL
Chen
Max Jin-Lung
MJ
Chang
King-Jen
KJ
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