title: Triceps surae muscle power, volume, and quality in older versus younger healthy men.
abstract: This study investigated whether loss of power with aging is fully accounted for by a decrease in muscle volume. Triceps surae power and volume (VOL) were measured in 18 older (OM: 69-82 years) and 12 younger men (YM: 19-35 years). Isokinetic peak torque was measured to determine torque-velocity and power-velocity relationships. Both peak power observed (PP(obs)) and peak power estimated from Hill's equation (PP(est)) were markedly reduced in the OM (PP(obs) was 45% and PP(est) was 43% of those of the YM). VOL was 81% of that of the YM (p <.001). Specific power (PP(est)/VOL) of the OM was 55.2% of that of the YM (p <.001). Torque at PP(est) accounted for a greater proportion of the decline in PP(est) in the OM than did optimum velocity (50% vs 13%, respectively). Hence, the present results showed that only approximately half of the loss in triceps surae peak power in old age is due to decreases in muscle VOL.
authors.affiliation: Institute for Biophysical and Clinical Research into Human Movement (IRM), Manchester Metropolitan University, Cheshire, Alsager Campus, Hassall Road, Alsager, Cheshire, ST7 2HL, United Kingdom. j.thom@mmu.ac.uk
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Thom
authors.forename: Chris I
authors.initials: CI
authors.lastname: Morse
authors.forename: Karen M
authors.initials: KM
authors.lastname: Birch
authors.forename: Marco V
authors.initials: MV
authors.lastname: Narici
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology; D012016:Reference Values