Effects of obesity and sex on the energetic cost and preferred speed of walking

Abstract

The metabolic energy cost of walking is determined, to a large degree, by body mass, but it is not clear how body composition and mass distribution influence this cost. We tested the hypothesis that walking would be most expensive for obese women compared with obese men and normal-weight women and men. Furthermore, we hypothesized that for all groups, preferred walking speed would correspond to the speed that minimized the gross energy cost per distance. We measured body composition, maximal oxygen consumption, and preferred walking speed of 39 (19 class II obese, 20 normal weight) women and men. We also measured oxygen consumption and carbon dioxide production while the subjects walked on a level treadmill at six speeds (0.50-1.75 m/s). Both obesity and sex affected the net metabolic rate (W/kg) of walking. Net metabolic rates of obese subjects were only approximately 10% greater (per kg) than for normal-weight subjects, and net metabolic rates for women were approximately 10% greater than for men. The increase in net metabolic rate at faster walking speeds was greatest in obese women compared with the other groups. Preferred walking speed was not different across groups (1.42 m/s) and was near the speed that minimized gross energy cost per distance. Surprisingly, mass distribution (thigh mass/body mass) was not related to net metabolic rate, but body composition (% fat) was (r2= 0.43). Detailed biomechanical studies of walking are needed to investigate whether obese individuals adopt novel energy saving mechanisms during walking.

The Effect of Water Depth on Energy Expenditure and Perception of Effort in Female Subjects While Walking

“…When compared with normal weight individuals, the obese have to expend more energy while walking. For example, the net metabolic rate of walking in overweight/ obese subjects is ∼10% and may be as much as 45% greater than in normal weight individuals (Browning & Kram, 2005;Browning, Baker, Herron, & Kram, 2006;Foster et al, 1995). This added metabolic cost places them at a greater percentage of their maximum aerobic capacity (VO 2peak ), making it more difficult to maintain recommended exercise durations.…”

Comparison of Energy Expenditure during Walking between Female Athletes and Non-Athletes

“…Hence, in order to make walking an activity for health and weight control, its energy expenditure should be measured accurately (Browning et al, 2006).…”

Gait Efficiency and the Use of Insolia® Flex to Promote First Metatarsophalangeal Joint Dorsiflexion

“…47 Studies of 'normal' weight individuals have shown that walking is less efficient when mass is placed on the lower legs or thighs compared with waist loads. 48 This increase could be due to the mechanical work required to swing the limb forwards which essentially have an increased mass and moment of inertia. 49 In this study, it was found that the Insolia  Flex significantly reduced the NoS.…”