Mechanical external work and recovery at preferred walking speed in obese subjects.
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.
Malatesta
Davide
D
Institute of Sport Sciences and Physical Education (ISSEP), University of Lausanne, Lausanne, Switzerland. davide.malatesta@unil.ch
Vismara
Luca
L
Menegoni
Francesco
F
Galli
Manuela
M
Romei
Marianna
M
Capodaglio
Paolo
P
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