An article published in the March issue of Sports Medicine and Health Science examines the relationships with Selected Constructs when Child Physical Activity is Measured by Child Self-Report, Parent Surrogate Report, and Accelerometry. The purposes of this study were to apply structural equation modeling in: 1) examining the associations between three distinct measures of physical activity and three factors that are often found to be correlated to physical activity in children, and 2) examining the associations of the combination of three measures with the same correlates in a cohort of youth followed from 5th to 7th grade. The study was undertaken in data from the Transitions and Activity Changes in Kids (TRACK) study. This study found that combining measures of physical activity from different sources may improve the identification of correlates of physical activity. This information could be used to plan more effective physical activity interventions in children and youth.