Child and Adolescent Differences in Economy at Various Speeds Across a Two- Year Time Period

Economy of movement is defined as the mass related aerobic demand (VO2 mL·kg⁻¹·min⁻¹) or energy expenditure required to run or walk at a given submaximal speed (Morgan, 2000). It has been well established that children have a lower economy compared to adults (Rowland and Green, 1988; Rowland et al., 1987; Unnithan and Eston, 1990). This means that at any given walking or running speed, children exhibit a higher weight relative VO₂ compared to that of an adult. The difference in economy between children and adults is thought to be due to differences in stride frequency (SF), leg length, body-surface-area to mass ratio (BSA:M), body mass index (BMI), and ventilatory efficiency (Rowland et al., 1987; Rowland and Green, 1988; Unnithan and Eston, 1990).