title: Explosive movement in the older men: analysis and comparative study of vertical jump.
abstract: BACKGROUND
  Loss of power has been demonstrated to have severe functional consequences to perform physical daily living tasks in old age.
  
  
  OBJECTIVE
  This study aimed to assess how moment and velocity were affected for each joint of the lower limbs during squat jumping for older men in comparison with young adults.
  
  
  METHODS
  Twenty-one healthy older men (74.5 ± 4.6 years) and 22 young men (21.8 ± 2.8 years) performed maximal squat jumps. Inverse dynamics procedure was used to compute the net joint power, moment and velocity produced at the hip, knee and ankle joints.
  
  
  CONCLUSIONS
  Vertical jump height of the elderly was 64 % lower than the young adults. The maximal power of the body mass center (Pmaxbmc) was 57 % lower in the older population. For the instant at Pmaxbmc, the vertical ground reaction force and the vertical velocity of the body mass center were 26 % and 35 % less in the older adults than in the young adults, respectively (p < 0.05; ES = -1.64 for vertical ground reaction force; p < 0.05; ES = -1.10). A lower value of the hip (-60 %), knee (-72 %) and ankle (-68 %) joint powers was observed in older adults. This was explained by both lower values of joint moments (-64, -57 and -61 % for the hip, knee and ankle, respectively) and angular velocities (-59, -49 and -52 % for the hip, knee and ankle, respectively).
  
  
  CONCLUSIONS
  This study showed a lower joint power when performing vertical jump. This smaller power resulted from both a lower moment and angular velocity produced at each joint.
authors.affiliation: Laboratoire Inter-Universitaire de Biologie de la Motricité (LIBM), Université Claude Bernard Lyon1, Lyon, France. sebastien.argaud@univ-lyon1.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Argaud
authors.affiliation: Institut de réadaptation en déficiences physique de Québec (IRDPQ), Quebec, QC, Canada.
authors.forename: Benoit
authors.initials: B
authors.lastname: Pairot de Fontenay
authors.affiliation: Laboratoire Inter-Universitaire de Biologie de la Motricité (LIBM), Université Claude Bernard Lyon1, Lyon, France.
authors.forename: Yoann
authors.initials: Y
authors.lastname: Blache
authors.affiliation: Laboratoire Inter-Universitaire de Biologie de la Motricité (LIBM), Université Claude Bernard Lyon1, Lyon, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Monteil
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Angular velocity; Moment; Power; Squat jump