title: Functional and morphological adaptations to aging in knee extensor muscles of physically active men.
abstract: It is not known if a physically active lifestyle, without systematic training, is sufficient to combat age-related muscle and strength loss. Therefore, the purpose of this study was to evaluate if the maintenance of a physically active lifestyle prevents muscle impairments due to aging. To address this issue, we evaluated 33 healthy men with similar physical activity levels (IPAQ = 2) across a large range of ages. Functional (torque-angle and torque-velocity relations) and morphological (vastus lateralis muscle architecture) properties of the knee extensor muscles were assessed and compared between three age groups: young adults (30 ± 6 y), middle-aged subjects (50 ± 7 y) and elderly subjects (69 ± 5 y). Isometric peak torques were significantly lower (30% to 36%) in elderly group subjects compared with the young adults. Concentric peak torques were significantly lower in the middle aged (18% to 32%) and elderly group (40% to 53%) compared with the young adults. Vastus lateralis thickness and fascicles lengths were significantly smaller in the elderly group subjects (15.8 ± 3.9 mm; 99.1 ± 25.8 mm) compared with the young adults (19.8 ± 3.6 mm; 152.1 ± 42.0 mm). These findings suggest that a physically active lifestyle, without systematic training, is not sufficient to avoid loss of strength and muscle mass with aging.
authors.affiliation: Exercise Research Laboratory, Physical Education School, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Bruno Manfredini
authors.initials: BM
authors.lastname: Baroni
authors.forename: Jeam Marcel
authors.initials: JM
authors.lastname: Geremia
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Rodrigues
authors.forename: Marcelo Krás
authors.initials: MK
authors.lastname: Borges
authors.forename: Azim
authors.initials: A
authors.lastname: Jinha
authors.forename: Walter
authors.initials: W
authors.lastname: Herzog
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Vaz
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology*; D009929:Organ Size / Q000502:physiology