Abstract
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.