title: Multiple joint muscle function with ageing: the force-velocity and power-velocity relationships in young and older men.
abstract: OBJECTIVE
  Whilst extensive research has detailed the loss of muscle strength with ageing for isolated single joint actions, there has been little attention to power production during more functionally relevant multiple joint movements. The extent to which force or velocity are responsible for the loss in power with ageing is also equivocal. The aim of this study was to evaluate the contribution of force and velocity to the differences in power with age by comparing the force-velocity and power-velocity relationships in young and older men during a multiple joint leg press movement.
  
  
  METHODS
  Twenty-one older men (66 ± 3 years) and twenty-three young men (24 ± 2 years) completed a series of isometric (maximum and explosive) and dynamic contractions on a leg press dynamometer instrumented to record force and displacement.
  
  
  RESULTS
  The force-velocity relationship was lower for the older men as reflected by their 19 % lower maximum isometric strength (p < 0.001). Explosive isometric strength (peak rate of force development) was 21 % lower for the older men (p < 0.05) but was similar between groups when normalised to maximum strength (p = 0.58). The power-velocity relationship was lower for the older men as shown by reduced maximum power (-28 %, p < 0.001) and lower force (-20 %, p < 0.001) and velocity (-11 %, p < 0.05).
  
  
  CONCLUSIONS
  Whilst force and velocity were lower in older men, the decrement in force was greater and therefore the major explanation for the attenuation of power during a functionally relevant multiple joint movement.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK. s.allison@lboro.ac.uk
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Allison
authors.forename: Katherine
authors.initials: K
authors.lastname: Brooke-Wavell
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Folland
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001696:Biomechanical Phenomena; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology*; D055815:Young Adult