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The effects of graded forward and backward walking on heart rate and oxygen consumption
Troy L Hooper1, David M Dunn, J Erick Props
1Department of Rehabilitation Sciences, School of Allied Health Sciences, Texas Tech University Heath Sciences Center, 3601 4th Street, Lubbock, Texas 79430, USA.
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 (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.
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