title: Comparison of maximal muscle strength of elbow flexors and knee extensors between younger and older men with the same level of daily activity.
abstract: BACKGROUND
  Aging promotes neuromuscular loss, significantly reducing muscle strength. The magnitude of loss of strength seems to be different between the limbs, probably because of differences in activities of daily living (ADL). Therefore, the present study compared the muscle strength of the elbow flexors and knee extensors in younger (n = 7, mean age 23.3 ± 1.2 years) and older (n = 5, mean age 61.8 ± 2.6 years) men matched by ADL level.
  
  
  METHODS
  The study participants performed maximal concentric, isometric, and eccentric contractions of the elbow flexors and knee extensors using an isokinetic dynamometer following a crossover study design. Changes in the dependent variables were compared using mixed model analysis (limb versus age).
  
  
  RESULTS
  The main results demonstrated that concentric, eccentric, and mean contraction torques for knee extensors were significantly (P < 0.05) higher for younger men than for elderly men. On the other hand, no statistically significant difference (P > 0.05) was found in concentric, isometric, eccentric, and mean torques for elbow flexors between younger and older individuals.
  
  
  CONCLUSIONS
  These results show that elbow flexors maintain better strength than knee extensors through aging, even when comparing individuals with similar ADL levels.
authors.affiliation: School of Physical Education, State University of Campinas, São Paulo, Brazil. felipedamasfl@gmail.com
authors.forename: Felipe Romano Damas
authors.initials: FR
authors.lastname: Nogueira
authors.forename: Cleiton Augusto
authors.initials: CA
authors.lastname: Libardi
authors.forename: Felipe Cassaro
authors.initials: FC
authors.lastname: Vechin
authors.forename: Manoel Emílio
authors.initials: ME
authors.lastname: Lixandrão
authors.forename: Ricardo Paes
authors.initials: RP
authors.lastname: de Barros Berton
authors.forename: Thiago Mattos Frota
authors.initials: TM
authors.lastname: de Souza
authors.forename: Miguel Soares
authors.initials: MS
authors.lastname: Conceição
authors.forename: Claudia Regina
authors.initials: CR
authors.lastname: Cavaglieri
authors.forename: Mara Patricia Traina
authors.initials: MP
authors.lastname: Chacon-Mikahil
mesh_terms: D000203:Activities of Daily Living; D000375:Aging / Q000502:physiology*; D018592:Cross-Over Studies; D004550:Elbow / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007717:Knee / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D019415:Torque; D055815:Young Adult
keywords: aging; concentric contraction; eccentric contraction; isometric contraction; sarcopenia