title: Effect of aging on human muscle architecture.
abstract: The effect of aging on human gastrocnemius medialis (GM) muscle architecture was evaluated by comparing morphometric measurements on 14 young (aged 27-42 yr) and on 16 older (aged 70-81 yr) physically active men, matched for height, body mass, and physical activity. GM muscle anatomic cross-sectional area (ACSA) and volume (Vol) were measured by computerized tomography, and GM fascicle length (Lf) and pennation angle (theta) were assessed by ultrasonography. GM physiological cross-sectional area (PCSA) was calculated as the ratio of Vol/Lf. In the elderly, ACSA and Vol were, respectively, 19.1% (P < 0.005) and 25.4% (P < 0.001) smaller than in the young adults. Also, Lf and were found to be smaller in the elderly group by 10.2% (P < 0.01) and 13.2% (P < 0.01), respectively. When the data for the young and elderly adults were pooled together, significantly correlated with ACSA (P < 0.05). Because of the reduced Vol and Lf in the elderly group, the resulting PCSA was found to be 15.2% (P < 0.05) smaller. In conclusion, this study demonstrates that aging significantly affects human skeletal muscle architecture. These structural alterations are expected to have implications for muscle function in old age.
authors.affiliation: Centre for Biophysical and Clinical Research into Human Movement (CRM Manchester Metropolitan University, Alsager Campus, Alsager, ST7 2HL, Cheshire, UK. m.narici@mmu.ac.uk
authors.forename: M V
authors.initials: MV
authors.lastname: Narici
authors.forename: C N
authors.initials: CN
authors.lastname: Maganaris
authors.forename: N D
authors.initials: ND
authors.lastname: Reeves
authors.forename: P
authors.initials: P
authors.lastname: Capodaglio
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000254:growth & development*; D014463:Ultrasonography