title: Age-Related Loss of Muscle Mass, Strength, and Power and Their Association With Mobility in Recreationally-Active Older Adults in the United Kingdom.
abstract: To investigate reasons for the age-related reduction in physical function, we determined the relationships between muscle size, strength, and power with 6-min walk distance (6MWD) and timed up-and-go performance in 49 young (23 ± 3.1 years) and 66 healthy, mobile older adults (72 ± 5 years). While muscle mass, determined by DXA and MRI, did not correlate with performance in the older adults, power per body mass, determined from a countermovement jump, did correlate. The 40% lower jumping power observed in older adults (p < .05) was due to a lower take-off velocity, which explained 34% and 42% of the variance in 6MWD in older women and men, respectively (p < .01). The lower velocity was partly attributable to the higher body mass to maximal force ratio, but most was due to a lower intrinsic muscle speed. While changes in muscle function explain part of the age-related reduction in functional performance, ~60% of the deficit remains to be explained.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Maden-Wilkinson
authors.forename: Jamie S
authors.initials: JS
authors.lastname: McPhee
authors.forename: David A
authors.initials: DA
authors.lastname: Jones
authors.forename: Hans
authors.initials: H
authors.lastname: Degens
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D055948:Sarcopenia / Q000503:physiopathology*; D016138:Walking / Q000502:physiology