Justus D Ortega1, Claire T Farley2. 1. Biomechanics Laboratory, Department of Kinesiology and Recreation Administration, Humboldt State University, CA, United States. Electronic address: jdo1@humboldt.edu. 2. Locomtion Laboratory, Department of Integrative Physiology, University of Colorado, CO, United States.
Abstract
PURPOSE: The metabolic cost of walking is greater in old compared to young adults. This study examines the relation between metabolic cost, muscular efficiency, and leg muscle co-activation during level and uphill walking in young and older adults. PROCEDURES: Metabolic cost and leg muscle activation were measured in young (22.3 ± 3.6 years) and older adults (74.5 ± 2.9 years) walking on a treadmill at six different slopes (0.0-7.5% grade) and a speed of 1.3 ms(-1). Across the range of slopes, 'delta mechanical efficiency' of the muscular system and antagonist muscle co-activation were quantified. MAIN FINDINGS: Across all slopes, older adults walked with a 13-17% greater metabolic cost, 12% lower efficiency, and 25% more leg muscle co-activation than young adults. Among older adults, co-activation was weakly correlated to metabolic cost (r=.233) and not correlated to the lower delta efficiency. CONCLUSION: Lower muscular efficiency and increased leg muscle co-activation contribute to the greater metabolic cost of uphill slope walking among older adults but are unrelated to one another.
PURPOSE: The metabolic cost of walking is greater in old compared to young adults. This study examines the relation between metabolic cost, muscular efficiency, and leg muscle co-activation during level and uphill walking in young and older adults. PROCEDURES: Metabolic cost and leg muscle activation were measured in young (22.3 ± 3.6 years) and older adults (74.5 ± 2.9 years) walking on a treadmill at six different slopes (0.0-7.5% grade) and a speed of 1.3 ms(-1). Across the range of slopes, 'delta mechanical efficiency' of the muscular system and antagonist muscle co-activation were quantified. MAIN FINDINGS: Across all slopes, older adults walked with a 13-17% greater metabolic cost, 12% lower efficiency, and 25% more leg muscle co-activation than young adults. Among older adults, co-activation was weakly correlated to metabolic cost (r=.233) and not correlated to the lower delta efficiency. CONCLUSION: Lower muscular efficiency and increased leg muscle co-activation contribute to the greater metabolic cost of uphill slope walking among older adults but are unrelated to one another.
Authors: David J Marcinek; Kenneth A Schenkman; Wayne A Ciesielski; Donghoon Lee; Kevin E Conley Journal: J Physiol Date: 2005-10-27 Impact factor: 5.182
Authors: Lisa A Zukowski; Jasmine M Martin; Gabrielle Scronce; Michael D Lewek; Prudence Plummer Journal: Eur J Appl Physiol Date: 2017-02-27 Impact factor: 3.078