The Effects of Graded Forward and Backward Walking on Heart Rate and Oxygen Consumption

Troy L. Hooper, David M. Dunn, J. Erick Props, Brandon A. Bruce, Steven F. Sawyer, John A. Daniel

DOI: 10.2519/jospt.2004.0883

Study Design: Single-group repeated-measures design. Objectives: 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 and Measures: 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 (VO_2max) 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 VO_2max 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 VO_2max than does forward walking under the same conditions and, if incorporated into sustained training regimens, would be expected to improve aerobic endurance.

J Orthop Sports Phys Ther. 2004;34(2):65-71. doi:10.2519/jospt.2004.0883

Key Words: aerobic conditioning, energy expenditure, gait, rehabilitation, retropulsion

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