title: The effects of graded forward and backward walking on heart rate and oxygen consumption.
abstract: METHODS
  Single-group repeated-measures design.
  
  
  OBJECTIVE
  To compare the effects of forward walking (FW) and backward walking (BW) on heart rate (HR) and oxygen consumption (VO2) at treadmill grades of 5%, 7.5%, and 10%.
  
  
  BACKGROUND
  Previous studies of locomotion by humans on a treadmill have reported larger cardiovascular exertion and potential biomechanical benefits of BW as compared to FW for treadmill grades ranging from 0% to 5%. The present study extends these findings by examining the cardiovascular effects of BW and FW at treadmill grades greater than 5%.
  
  
  METHODS
  Twenty-nine volunteers participated in this study. Two subjects were excluded, leaving 27 study subjects (15 females, 12 males; mean age +/- SD, 24.0 +/- 3.4 years). VO2 and HR were measured using open-circuit calorimetry and electrocardiogram, respectively. For both forward and backward walking, subjects performed each of the 3 grades for 6 minutes, during which HR and VO2 were measured. Two-way repeated-measures ANOVAs were employed for inferential statistical analysis.
  
  
  RESULTS
  Percent maximum heart rate (HR(max)) and percent maximum oxygen consumption (VO2(max)) increased incrementally for treadmill grades of 5% to 7.5% to 10% for both FW and BW (P < .00001). For each of the 3 treadmill grades, percent HR(max) and percent VO2(max) was 17% to 20% higher for BW than for FW (P < .00001). No statistically significant interactions were detected between direction of walking and treadmill grade.
  
  
  CONCLUSIONS
  Backward walking on a treadmill at 67.0 m/min (2.5 mph) and grades of 5%, 7.5%, and 10% elicits a greater percent HR(max) and percent VO2(max) than does forward walking under the same conditions and, if incorporated into sustained training regimens, would be expected to improve aerobic endurance.
authors.affiliation: Department of Rehabilitation Sciences, School of Allied Health Sciences, Texas Tech University Heath Sciences Center, 3601 4th Street, Lubbock, Texas 79430, USA.
authors.forename: Troy L
authors.initials: TL
authors.lastname: Hooper
authors.forename: David M
authors.initials: DM
authors.lastname: Dunn
authors.forename: J Erick
authors.initials: JE
authors.lastname: Props
authors.forename: Brandon A
authors.initials: BA
authors.lastname: Bruce
authors.forename: Steven F
authors.initials: SF
authors.lastname: Sawyer
authors.forename: John A
authors.initials: JA
authors.lastname: Daniel
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002320:Cardiovascular Physiological Phenomena; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D016138:Walking / Q000502:physiology*