title: Aging-related differences in maximum force, unloaded velocity and power of human leg multi-joint movement.
abstract: BACKGROUND
  Because many of our movements of daily living are multi-joint movements and lower limb performance decreases with aging, it is important to understand the influence of aging on muscle functions of lower limb multi-joint movements.
  
  
  OBJECTIVE
  To investigate aging-related differences in the maximum force, unloaded velocity and power of muscles that control leg multi-joint movements.
  
  
  METHODS
  285 recreationally active men (n = 142) and women (n = 143) aged between 18 and 82 years volunteered for the study. Lower limb muscle function was measured with a servo-controlled dynamometer and the maximum isometric force (F(max)), unloaded velocity (V(max)) and power (P(max)) were determined by the force-velocity and force-power relations.
  
  
  RESULTS
  With increasing age, F(max)/body mass significantly declines in both men (r = -0.400, p <0.001) and women (r = -0.587, p < 0.001), while V(max)/leg length does not change with age in either men (r = -0.033, p > 0.05) or women (r = -0.040, p > 0.05). P(max) significantly declines with age in both men (r = -0.370, p < 0.001) and women (r = -0.446, p < 0.001).
  
  
  CONCLUSIONS
  Aging does not have effects on the shortening velocity, although it causes a decrease in maximum force and power of leg multi-joint movements. This finding suggests that decreases in muscle force-generating capacity and power may primarily lead to the loss of mobility and a reduced capability of accelerating and decelerating the body mass during the movements in elderly individuals.
authors.affiliation: Institute of Sport Science, Friedrich-Schiller University Jena, Germany. yamauchi@tmu.ac.jp
authors.forename: Junichiro
authors.initials: J
authors.lastname: Yamauchi
authors.forename: Chizuko
authors.initials: C
authors.lastname: Mishima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakayama
authors.forename: Naokata
authors.initials: N
authors.lastname: Ishii
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007596:Joints / Q000502:physiology*; D007866:Leg / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D012727:Sex Characteristics; D055815:Young Adult