title: Effects of cadence on energy generation and absorption at lower extremity joints during gait.
abstract: BACKGROUND
  Information regarding kinetic changes associated with walking speed is important for identifying alterations in locomotor disorders caused by pathological processes, as opposed to those arising solely from altered speeds.
  
  
  METHODS
  Fourteen healthy subjects were assessed walking at both natural and imposed cadences of 60, 80, and 120 steps/min. A 3D motion analysis system, force platforms, and related software were used to obtain kinematic and kinetic data. Net joint powers were calculated across cycles and the area under the positive and negative phases of the power curves provided the mechanical work generated and absorbed at the hip, knee, and ankle. The relative contributions to the total positive and negative work across the four cadences were calculated for each joint. ANOVAs followed by planned contrasts were used to assess the effects of laterality, joint, and cadence.
  
  
  RESULTS
  Power and mechanical work, as well as the contributions of individual joints to the total energy generated and absorbed, were shown to be influenced by walking cadence, independent of laterality. The ankle, knee, and hip contributions to the total limb generation and absorption at the lowest cadence were 53%, 21%, and 26%, and at the highest cadence, the corresponding values were 34%, 33%, and 33%, respectively.
  
  
  CONCLUSIONS
  Power and mechanical work, as well as the contributions of individual joints to the total energy generated and absorbed, were shown to be influenced by the walking cadence, independent of laterality. These findings will be helpful for identifying walking strategies and adaptations in populations with gait disorders.
authors.affiliation: Department of Physical Therapy, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, Campus Pampulha, 31270-010 Belo Horizonte, Minas Gerais, Brazil. lfts@ufmg.br
authors.forename: Luci Fuscaldi
authors.initials: LF
authors.lastname: Teixeira-Salmela
authors.forename: Sylvie
authors.initials: S
authors.lastname: Nadeau
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Milot
authors.forename: Denis
authors.initials: D
authors.lastname: Gravel
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Requião
mesh_terms: D000843:Ankle Joint / Q000502:physiology*; D003198:Computer Simulation; D004735:Energy Transfer / Q000502:physiology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007866:Leg / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D005082:Physical Exertion / Q000502:physiology*; D016138:Walking / Q000502:physiology*