The Effect of a Backpack Hip Strap on Energy Expenditure While Walking.

Abstract

Previous studies have demonstrated that the energy cost of carrying a backpack increases as the mass of the load carried increases. Conflicting results have been found when research examined the effect of duration on energy expenditure while carrying a backpack. A potential confounding variable could be the design of the backpack, particularly the use of a backpack hip strap. PURPOSE: To examine the effect of backpack hip strap use on walking energy expenditure while carrying a loaded backpack. METHODS: A crossover design was used in which fifteen young, healthy male subjects walked at a self-selected pace for two 10-minutes in two backpack loading conditions: with a hip strap (strapped) and without a hip strap (non-strapped). Oxygen consumption (VO2), rating of perceived exertion (RPE), respiratory exchange ratio (RER), and heart rate (HR) were monitored throughout each 10-minute trial. Change scores from the 4th to 10th minute were calculated for each variable. A t-test was used to evaluate the difference between conditions for each variable. RESULTS: The change in VO2 (-0.62 ± 0.40 vs. 0.33 ± 0.23, p = 0.04) and change in RPE (1 ± 0.25 vs. 2 ± 0.21, p &lt 0.01) from the 4th to the 10th minute were different for the strapped versus non-strapped condition, respectfully. There was no difference in the change in RER (0.04 ± 0.01 vs. 0.03 ± 0.01, p &gt 0.05) or HR (3.53 ± 0.93 vs. 4.07 ± 1.39, p &gt 0.05) for the strapped versus unstrapped condition, respectfully. CONCLUSIONS: Wearing a hip strap reduced the energy expenditure and perceived exertion in as little as 10 minutes of walking compared the non-strapped condition. Future work should consider the effect of a hip strap on these variables while hiking for extended periods.