title: Energetic costs of incidental visual coupling during treadmill running.
abstract: OBJECTIVE
  To determine the role of visual-spatial information in stabilizing movement during treadmill locomotion.
  
  
  METHODS
  Physiological, biomechanical, and psychological indices of coordination stability were recorded while participants were visually coupled with a whole-body image of themselves during treadmill locomotion. Ten participants ran on a treadmill under three visual conditions: two dynamic images (symmetrical, mirror image; asymmetrical, reversed mirror image) and one static. Performance was examined at two speeds.
  
  
  RESULTS
  Participants ran more economically (mL x kg x min(-1)) when they were visually coupled with a symmetrical rather than with an asymmetrical or static image. An asymmetrical coupling resulted in increased variability in footfall position at the faster speed, in comparison to the symmetrical and static conditions. However, at slower speeds, footfall variability and frequency were higher under both dynamic visual conditions in comparison to the static control. Changes in metabolic economy (mL x kg x min(-1)) were only partially mediated by movement kinematics.
  
  
  CONCLUSIONS
  Visual information influences treadmill locomotion and associated measures of stability even when there is no intention to coordinate with external stimuli.
authors.affiliation: School of Social Sciences and Law, The University of Teesside, Middlesbrough, United Kingdom. d.eaves@tees.ac.uk
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Eaves
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Hodges
authors.forename: A Mark
authors.initials: AM
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D004734:Energy Metabolism / Q000502:physiology*; D004739:England; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D011597:Psychomotor Performance / Q000502:physiology*; D012420:Running / Q000502:physiology