title: Mechanical external work and recovery at preferred walking speed in obese subjects.
abstract: OBJECTIVE
  The aim of this study was to compare the mechanical external work (per kg) and pendular energy transduction at preferred walking speed (PWS) in obese versus normal body mass subjects to investigate whether obese adults adopt energy conserving gait mechanics.
  
  
  METHODS
  The mechanical external work (Wext) and the fraction of mechanical energy recovered by the pendular mechanism (Rstep) were computed using kinematic data acquired by an optoelectronic system and were compared in 30 obese (OG; body mass index [BMI] = 39.6 +/- 0.6 kg m(-2); 29.5 +/- 1.3 yr) and 19 normal body mass adults (NG; BMI = 21.4 +/- 0.5 kg m(-2); 31.2 +/- 1.2 yr) walking at PWS.
  
  
  RESULTS
  PWS was significantly lower in OG (1.18 +/- 0.02 m s(-1)) than in NG (1.33 +/- 0.02 m s(-1); P <or= 0.001). There was no significant difference in Wext per unit mass between groups (OG: 0.36 +/- 0.03 J kg(-1) m(-1); NG: 0.31 +/- 0.02 J kg(-1) m(-1); P = 0.12). Rstep was significantly lower in OG (68.4% +/- 2.0%) compared with NG (74.4% +/- 1.0%; P = 0.01). In OG only, Wext per unit mass was positively correlated with PWS (r = 0.57; P < 0.001).
  
  
  CONCLUSIONS
  Obese adults do not appear to alter their gait to improve pendular energy transduction and may select slower PWS to reduce mechanical and metabolic work.
authors.affiliation: Institute of Sport Sciences and Physical Education (ISSEP), University of Lausanne, Lausanne, Switzerland. davide.malatesta@unil.ch
authors.forename: Davide
authors.initials: D
authors.lastname: Malatesta
authors.forename: Luca
authors.initials: L
authors.lastname: Vismara
authors.forename: Francesco
authors.initials: F
authors.lastname: Menegoni
authors.forename: Manuela
authors.initials: M
authors.lastname: Galli
authors.forename: Marianna
authors.initials: M
authors.lastname: Romei
authors.forename: Paolo
authors.initials: P
authors.lastname: Capodaglio
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D005082:Physical Exertion / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D055815:Young Adult