Abstract
Introduction: Few physical activity interventions have been undertaken in infants and toddlers, despite concerns that they are insufficiently active. The Prevention of Overweight in Infancy trial encouraged parents to be physically active with their child from birth, including prone-based play ("tummy time"), while reducing time spent restrained in car seats and "strollers." Methods: A total of 802 women, recruited in late pregnancy, were randomized to a physical activity intervention, which provided information antenatally, and active group sessions with their infant at 3, 9, and 18 months of age. Questionnaires were completed at multiple time points, and toddlers wore Actical accelerometers for 5 d at 24 months of age. Results: Attendance at intervention sessions was high in infancy but declined by 18 months to 66%. Almost all parents placed their infant prone to play at least once a day (90%-95%, overall median 25 min.d(-1)), with no intervention differences observed (P = 0.445 and P = 0.350 at 4 and 6 months, respectively). Few differences were observed in other measures of restraint or parental activity at any time point. At 2 yr, children spent approximately 8 h.d(-1) in sedentary time while awake and 3.6 h in light-to-vigorous activity. However, no group differences were apparent in counts per minute (P = 0.759) or time in light-to-vigorous activity (P = 0.960). Conclusion: An early life intervention targeting improvements in child and parent physical activity as part of a wider obesity prevention initiative had little effect on physical activity at 2 yr of age.