Author(s): HUANG, W., FENG, J., Institution: HONG KONG BAPTIST UNIVERSITY, Country: CHINA, Abstract-ID: 960

INTRODUCTION:
Novel cut-point-free accelerometer metrics, such as average acceleration (volume) and intensity gradient (intensity distribution), offer alternative approaches for quantifying how children engage in physical behaviours. However, their potential to reveal intervention effects that may be obscured by traditional threshold-based analyses remains underexplored. The purpose of this study was to examine the effects of a parent-focused intervention targeting preschoolers’ 24-hour movement behaviours on these accelerometer-derived metrics.
METHODS:
This secondary analysis of a 12-week randomised controlled trial (RCT) included 147 preschoolers aged 3 to 5.9 years and their parents, who were randomly assigned to either an integrated intervention (targeting all three behaviours), a dyadic intervention (targeting physical activity and sedentary behaviour), or a wait-list control group. The intervention group received educational materials and reminders, attended workshops, and completed interactive questionnaires. Children’s movement behaviours were assessed using a wrist-worn ActiGraph accelerometer for seven consecutive 24-hour periods at baseline, week 12 (post-intervention), and week 24 (follow-up). Linear mixed models were conducted to evaluate intervention effects on average acceleration and intensity gradient.
RESULTS:
Of the 147 children randomised (4.8 ± 0.9 years, 56.5% boys), ActiGraph data from 103 children were successfully processed using the GGIR package. Compared to the control group, the dyadic intervention group demonstrated increases in both average acceleration (6.26 mg; 95% CI: 0.92 to 11.60; p = 0.022) and intensity gradient (0.10; 95%CI: 0.00 to 0.20; p = 0.050) after the intervention. No significant differences were observed between the integrated intervention and control groups at either post-intervention or follow-up.
CONCLUSION:
The findings indicate that interventions targeting waking physical activity and sedentary behaviour can effectively increase overall physical activity volume and promote a shift in activity intensity. Although the original analysis of this RCT did not find significant intervention effects on time spent in moderate-to-vigorous physical activity, this secondary analysis using cut-point-free metrics provides new insights into the quality and intensity of children’s movement patterns throughout the day.