title: Strength and fatigue of lumbar extensor muscles in older adults.
abstract: BACKGROUND
  Loss of lumbar extensor muscle strength and fatigue resistance may contribute to functional disability.
  
  
  METHODS
  Two groups of subjects were recruited: young (n = 26, 20-35 years of age) and old (n = 26, ≥65 years of age) adults. Lumbar extensor muscle strength was measured with a load cell, and electromyographic activities were recorded to study muscle fatigue at 60% of maximum voluntary contraction.
  
  
  RESULTS
  We found that the muscle moments generated by the extensor muscles decreased with age (P < 0.05). Aging was associated with a significant increase in the power of the lower frequency band (101-200 Hz) of the electromyographic signals (P < 0.05), but the spectral characteristics did not appear to change with sustained contraction (P > 0.05).
  
  
  CONCLUSIONS
  The changes in strength and spectral properties of the electromyographic signals of lumbar extensor muscles may be related to age-related alterations in muscle fiber composition and recruitment. These changes should be considered in clinical functional task evaluation.
authors.affiliation: Faculty of Health Sciences, Jalan Raja Muda Aziz, National University of Malaysia, Kuala Lumpur, Malaysia.
authors.forename: Devinder Kaur
authors.initials: DK
authors.lastname: Ajit Singh
authors.forename: Martin
authors.initials: M
authors.lastname: Bailey
authors.forename: Raymond
authors.initials: R
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015331:Cohort Studies; D004576:Electromyography / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D008161:Lumbosacral Region / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D055815:Young Adult