Postural control strategies differ in normal weight and overweight infants

Background: Evidence suggests obesity can have a negative influence on a child's motor development and postural control behavior. Little research has examined the impact of infant weight on gross motor behavior, particularly postural control at the onset of sitting. Objective: The purpose of this study was to determine whether normal weight and overweight infants differed in their postural control strategies at the onset of sitting and one-month post onset of sitting. Methods: 29 infants (n = 19 normal weight, n = 10 overweight) were recruited to participate in this study. Infant's length and weight were measured at 3 months of age (visit 1). Infant's center of pressure (COP) was measured on an AMTI force platform at the onset of sitting (visit 2) and one-month post onset (visit 3). Data were analyzed using linear measures (range and RMS for the anterior/posterior (AP) and medial/lateral (ML) directions, sway path) and nonlinear measures (Sample Entropy in AP and ML directions). Results: Overweight infants had significantly greater RMS values in the ML direction at visit 2 and reduced Sway Path values in comparison to normal weight infants at visits 2 and 3. Further, there was a significant difference in Sample Entropy as overweight infants increased Sample Entropy from visit 2 to 3 while normal weight infants decreased Sample Entropy values during this time period. Conclusions: These findings suggest that overweight infants adopt a different postural control strategy. This altered strategy may limit exploration early in development. More research is needed to determine if longitudinal differences continue to emerge.