Abstract
Metabolic energy expenditure (MEE) is a primary determinant of gait, and joint loading may be as well. Externally loading an individual may require balancing these determinants when walking. PURPOSE: The purpose of this study was to investigate the effects of reducing vertical ground reaction forces (vGRF) through feedback on gross metabolic power. We hypothesized that reducing vGRF would come at the cost of greater MEE. METHODS: Twelve healthy participants (6 males [BMI = 22.19 ± 1.57]; 6 females [BMI = 20.12 ± 1.33]) between 20-25 years of age completed three 10-minute walking trials on an instrumented treadmill at 1.4 m·s-1 with no load, 15% body-weight (BW) and 30% BW (weighted vest). The participants received no feedback for the first five minutes, then during the second five minutes, they were told to lower peak vertical ground reaction forces based on visual feedback of those forces. Expired gases were collected to estimate MEE using the Brockway equation, then normalized by body mass (BM) and body mass plus external load (BMEL). A 2-way ANOVA (p < 0.05) was used to compare main effects of feedback and load for each of the load normalizations. RESULTS: The feedback conditions had significantly greater MEE than no feedback across the different loads (p < 0.001) for both normalization methods (Fig 1). The MEE increased significantly with greater loads for feedback and no-feedback with BM normalization (p < 0.001) but did not differ significantly with BMEL normalization (p = 0.177) (Fig 1). CONCLUSION: As participants tried to lower peak vertical ground reaction forces, MEE increased, suggesting an interaction of loads and MEE while walking. Similar to previous studies, MEE increases when deviating from preferred gait mechanics. We found that when accounting for the BMEL, MEE decreased as external load increased, that is opposite to BM normalization alone. Including BMEL may allow better understanding about how we metabolically accommodate to increasing loads.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
