Investigating the correlation between paediatric stride interval persistence and gross energy expenditure

This study tested for correlations between stride interval persistence and measures of energy expenditure including mass-specific gross oxygen consumption per minute (), mass-specific gross oxygen cost per meter (VO2) and heart rate (HR). Metabolic and stride interval data were collected from 30 asymptomatic children who completed one 10-minute walking trial under each of the following conditions: (i) overground walking, (ii) hands-free treadmill walking, and (iii) handrail-supported treadmill walking. Stride interval persistence was not significantly correlated with (p > 0.32), VO2 (p > 0.18) or HR (p > 0.56).No simple linear dependence exists between stride interval persistence and measures of gross energy expenditure in asymptomatic children when walking overground and on a treadmill.The human stride interval (i.e., the time between consecutive heel strikes of the same foot) exhibits statistical persistence, with correlations extending over thousands of strides [1]. This persistence is typically quantified in terms of α, a scaling estimate provided by detrended fluctuation analysis (DFA) [1,2]. To date, α has been found to change across the age spectrum, when certain neuromuscular disorders exist, and during some pace-constrained walking tasks [2-4].Interestingly, physiological cost has demonstrated similar sensitivities to age, disease, and tempo-constrained locomotion with increased energy requirements having been linked to advanced ageing [5], pathology [6], and forced-rate stepping [7]. Given that stride interval dynamics are thought to reflect a certain extent of locomotor control [2], and that human locomotion is shaped by a preference for energy efficient movements [8], we hypothesized that energy and scaling measures would exhibit a certain degree of dependence. Specifically, we expected that decreased stride interval persistence would be associated with increased energy expenditure and vice versa.The first study to investigate this dependence found no as