title: Mechanical muscle function, morphology, and fiber type in lifelong trained elderly.
abstract: OBJECTIVE
  Maximal muscle contraction force and muscle mass are both reduced during the natural aging process. Long-term training may be used to attenuate this age-related loss in muscle function and muscle size.
  
  
  METHODS
  Maximum isometric quadriceps strength (MVC), rate of force development (RFD), and muscle fiber composition and size (CSA) were studied in elderly individuals (68-78 yr) chronically exposed (> 50 yr) to either endurance (E) or strength (S) training, and in age-matched, untrained (U) elderly group.
  
  
  RESULTS
  E and S showed greater MVC than did U. Contractile RFD was elevated in S compared with U, and S also demonstrated greater type II fiber CSA than did U and E. The proportion of type I fibers was greater in E compared with U and S.
  
  
  CONCLUSIONS
  Muscle fiber size and mechanical muscle performance, particularly RFD, were consistently elevated in aged individuals exposed to chronic (i.e., lifelong) strength training. This relative preservation in muscle morphology and function may provide an important physical reserve capacity to retain muscle mass and function above the critical threshold for independent living at old age.
authors.affiliation: Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark. paagaard@health.sdu.dk
authors.forename: Per
authors.initials: P
authors.lastname: Aagaard
authors.forename: Peter S
authors.initials: PS
authors.lastname: Magnusson
authors.forename: Benny
authors.initials: B
authors.lastname: Larsson
authors.forename: Michael
authors.initials: M
authors.lastname: Kjaer
authors.forename: Peter
authors.initials: P
authors.lastname: Krustrup
mesh_terms: D000368:Aged; D003718:Denmark; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D052097:Quadriceps Muscle / Q000033:anatomy & histology / Q000502:physiology*