title: Minimal energetic expenditure of women walking burdened on gradients in urban environments.
abstract: OBJECTIVE
  The objective is to understand the walking energy expenditure of women in urban environments (i.e., over-ground), using mass, velocity, gradient (incline and decline), and burden as predictors. In addition, we use an equation to determine the gradient associated with the minimum energy expenditure of walking.
  
  
  METHODS
  To do this, we assessed the volumetric consumption of oxygen (VO2) of ten females (ages: 22-40 years) with a portable Cosmed K4b2device. Participants walked at three self-selected, over-ground velocities (slow, normal, and fast) on five gradients (0%, +/-7.5%, +/- 12.4%) in different urban community settings burdened (10 kg) and unburdened. We performed a multilinear regression controlling for repeated measures to determine the best predictive equation for VO2. The first derivative of our equation was used to find the gradient for minimal VO2.
  
  
  RESULTS
  Our equation explains 79% of the variation in VO2and indicates that over-ground walking is similar to treadmill walking, except that the gradient associated with the minimal energy expenditure of walking is steeper (-11% to -20%) than that established from treadmill walking.
  
  
  CONCLUSIONS
  Although our overall equation is an accurate predictor of VO2for all velocities, burden, incline, and decline in this group, further research needs to be conducted to examine kinetic, kinematic, and velocity interactions in over-ground walking.
authors: Department of Anthropology, University of Washington, Seattle, Washington, 98195-3100.|Department of Biology, University of Washington, Seattle, Washington, 98195-3100.
authors: Megan J
authors: MJ
authors: Rue
authors: Department of Anthropology, University of Washington, Seattle, Washington, 98195-3100.|Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington, 98195-3100.
authors: Patricia A
authors: PA
authors: Kramer
mesh_terms: D000328:Adult; D002947:Cities; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008962:Models, Theoretical; D010101:Oxygen Consumption; D016138:Walking; D000076251:Wearable Electronic Devices; D014930:Women; D055815:Young Adult
keywords: burden; gradients; minimal VO2; walking outside; women