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Previous studies have demonstrated that energy cost increases as the weight of the load increases, but few investigations have been conducted that focus on backpack carriage specifically. 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 15 young, healthy male subjects walked at a self-selected pace for two 10-minute loaded backpack trials either with a hip strap (strapped) or without a hip strap (non-strapped). Oxygen consumption (VO 2 ), rating of perceived exertion (RPE), respiratory exchange ratio (RER), and heart rate (HR) were monitored throughout each 10-minute trial. Change scores from the 4 th to 10 th minute were calculated for each variable. A t-test was used to evaluate the difference between trials for each variable. RESULTS: The change in VO 2 (-0.62±0.40 vs. 0.33±0.23, p=0.04) and RPE (1±0.25 vs. 2±0.21, p<0.01) from the 4 th to the 10 th minute were different for the strapped versus non-strapped condition, respectively. There was no difference in the change in RER (0.04±0.01 vs. 0.03±0.01, p>0.05) or HR (3.53±0.93 vs. 4.07±1.39, p>0.05) for the strapped versus unstrapped condition, respectively. CONCLUSIONS: These results suggest wearing a hip strap reduces the energy expenditure and perceived exertion in as little as 10 minutes of walking. The reduced energy expenditure found with using a hip strap may have a significant impact on an individual's ability to hike or march for extended periods of time.

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Background Exercise has failed to reduce falls in those with chronic stroke. A limitation of traditional exercise is that the motor responses needed to prevent a fall are not elicited (i.e. they lack processing specificity ). Balance reactions often require compensatory steps. Therefore, interventions that target such steps have the potential to reduce falls. Computerized treadmills can deliver precise, repeatable, and challenging perturbations as part of a training protocol. The objective of this study was to develop and determine the feasibility of such training applied to those with chronic stroke. We developed the training to address specificity, appropriate duration and repetition, and progressive overloading and individualization. We hypothesized that our intervention would be acceptable, practical, safe, and demonstrate initial signs of efficacy. Methods In this single-arm study, thirteen individuals with chronic stroke (29–77 years old, 2–15 years post stroke) performed up to six training sessions using a computer-controlled treadmill. Each session had separate progressions focused on initial steps with the non-paretic or paretic limbs in response to anterior or posterior falls. Perturbation magnitudes were altered based on performance and tolerance. Acceptability was determined by adherence, or the number of sessions completed. Practicality was documented by the equipment, space, time, and personnel. Adverse events were documented to reflect safety . In order to determine the potential-efficacy of this training, we compared the proportion of successful recoveries and the highest perturbation magnitude achieved on the first and last sessions. Results The training was acceptable , as evident by 12/13 participants completing all 6 sessions. The protocol was practical , requiring one administrator, the treadmill, and a harness. The protocol was safe , as evident by no serious or unanticipated adverse events. The protocol demonstrated promising signs of efficacy . From the first to last sessions, participants had a higher proportion of successful recoveries and progressed to larger disturbances. Conclusions Using a computerized treadmill, we developed an approach to fall-recovery training in individuals with chronic stroke that was specific, considered duration and repetition, and incorporated progressive overloading and individualization. We demonstrated that this training was acceptable, practical, safe, and potentially beneficial for high-functioning individuals with chronic stroke. Trial registration Retrospectively registered at clinicaltrials.gov ( NCT03638089 ) August 20, 2018.