Exploring Factors Associated With Accelerometer Validity Among Ethnically Diverse Toddlers

PURPOSE

Studying physical activity in toddlers using accelerometers is challenging due to noncompliance with wear time (WT) and activity log (AL) instructions. The aims of this study are to examine relationships between WT and AL completion and (1) demographic and socioeconomic variables, (2) parenting style, and (3) whether sedentary time differs by AL completion.

METHODS

Secondary analysis was performed using baseline data from a community wellness program randomized controlled trial for parents with toddlers (12-35 mo). Parents had toddlers wear ActiGraph wGT3x accelerometers and completed ALs. Valid days included ≥600-minute WT. Analysis of variance and chi-square analyses were used.

RESULTS

The sample (n = 50) comprised racial and ethnically diverse toddlers (mean age = 27 mo, 58% male) and parents (mean age = 31.7 y, 84% female). Twenty-eight families (56%) returned valid accelerometer data with ALs. Participants in relationships were more likely to complete ALs (P < .05). Toddler sedentary time did not differ between those with ALs and those without.

CONCLUSIONS

We found varied compliance with WT instructions and AL completion. Returned AL quality was poor, presenting challenges in correctly characterizing low-activity counts to improve internal validity of WT and physical activity measures. Support from marital partners may be important for adherence to study protocols.

Techniques to measure free-living energy expenditure during pregnancy - A guide for clinicians and researchers

As maternal overweight and obesity increase in prevalence, the need to optimise gestational weight gain has entered the forefront due to the well-documented poor fetal and maternal outcomes associated with excess adipose tissue. Measurements of changes in energy expenditure form crucial components of effective weight management programmes, and they are also important for clarifying the energy requirements of pregnancy. This review evaluates the primary techniques for measuring free-living energy expenditure for use in pregnancy, with special consideration of the dynamic physiological changes that occur in this state. The methods that will be discussed include the doubly labelled water method, activity recall and activity logs, heart rate monitors and motion sensors. This article may be useful for clinicians seeking to implement active gestational weight management by enabling advice on increases in caloric intake linked to measured changes in energy expenditure, and for researchers studying energy metabolism in pregnancy.