Characteristics of tummy time and dose-response relationships with development in infants

This study aimed to examine change in tummy time patterns and preferences in the first 6 months of life, as well as dose–response relationships between tummy time duration and development at 2, 4, and 6 months. Participants were parents of infants from the Early Movers project in Edmonton, Canada (baseline: n = 411). At 2, 4, and 6 months, infant tummy time duration and preference (i.e., 1 = really likes to 5 = really dislikes) and development (i.e., Ages & Stages Questionnaire (ASQ-3) communication, fine motor, gross motor, problem-solving, personal-social) were measured by a parental questionnaire. In a subsample (n = 127), tummy time patterns (i.e., bout frequency, mean and median bout length) were measured using a 3-day time-use diary. Tummy time bout frequency, bout length, and preference significantly increased over time. Linear dose–response relationships between tummy time duration and development outcomes were observed at 4 (gross motor) and 6 months (all development outcomes). Moreover, at 2 months, 30–44 min/day of tummy time was associated with a higher total development score (vs. < 15 min/day; B = 11.14; 95%CI: 1.60, 20.68). At 6 months, 61–120 min/day (vs. < 30 min/day; B = 27.12; 95%CI: 11.93, 42.32) and > 120 min/day (vs. < 30 min/day; B = 33.80; 95%CI: 18.90, 48.70) of tummy time were associated with higher total development scores. Differences in threshold doses between some developmental outcomes were observed. Conclusion: In the first 6 months of life, increases were observed in tummy time preference as well as tummy time bout frequent and length. This finding may explain why the optimal amount of tummy time needed for more advanced development appeared to increase with age.What is Known:• Tummy time is a type of physical activity in infancy. International and national guidelines recommend at least 30 minutes of tummy time per day for infants who are not yet mobile.What is New:• In the first six months of life, preference for tummy time as well as tummy time bout frequency and length increased.• Tummy time duration had dose-response associations with several development outcomes, and the optimal amount of tummy time needed for more advanced development appeared to increase with age.