Investigating the relationship between energy expenditure, walking speed and angle of turning in humans

• Published in: PloS one Vol. 12; no. 8; p. e0182333
• Main Authors: McNarry, M A, Wilson, R P, Holton, M D, Griffiths, I W, Mackintosh, K A
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.08.2017; Public Library of Science (PLoS)
• Subjects: Ability tests; Accelerometers; Activities of daily living; Adult; Adults; Biology and Life Sciences; Energy expenditure; Energy Metabolism; Engineering and Technology; Exercise; Exercise Test; Female; Fitness equipment; Gas exchange; Health care; Heart failure; Humans; Interaction parameters; Investigations; Laboratories; Male; Medicine and Health Sciences; Oxygen; Oxygen Consumption; Oxygen uptake; Physical Exertion; Physical fitness; Physical Sciences; Physiological aspects; Professional soccer; Running; Social Sciences; Studies; Walking; Walking Speed - physiology; Weight control; Young Adult; United Kingdom
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0182333

Recent studies have suggested that changing direction is associated with significant additional energy expenditure. A failure to account for this additional energy expenditure of turning has significant implications in the design and interpretation of health interventions. The purpose of this study was therefore to investigate the influence of walking speed and angle, and their interaction, on energy expenditure in 20 healthy adults (7 female; 28±7 yrs). On two separate days, participants completed a turning protocol at one of 16 speed- (2.5, 3.5, 4.5, 5.5 km∙h-1) and angle (0, 45, 90, 180°) combinations, involving three minute bouts of walking, interspersed by three minutes seated rest. Each condition involved 5 m of straight walking before turning through the pre-determined angle with the speed dictated by a digital, auditory metronome. Tri-axial accelerometry and magnetometry were measured at 60 Hz, in addition to gas exchange on a breath-by-breath basis. Mixed models revealed a significant main effect for speed (F = 121.609, P < 0.001) and angle (F = 19.186, P < 0.001) on oxygen uptake ([Formula: see text]) and a significant interaction between these parameters (F = 4.433, P < 0.001). Specifically, as speed increased, [Formula: see text] increased but significant increases in [Formula: see text] relative to straight line walking were only observed for 90° and 180° turns at the two highest speeds (4.5 and 5.5 km∙hr-1). These findings therefore highlight the importance of accounting for the quantity and magnitude of turns completed when estimating energy expenditure and have significant implications within both sport and health contexts.