Research indicates that sleeping on the back is related to slower gross motor development in babies. (candokiddo.com)
It develops hand - eye coordination and fine motor development for infants, verbal skills for toddlers, and cognitive, social, emotional, and physical development for preschoolers. (care.com)
You can read about gross motor development in the 9 - 12 month period at our web page for more tips and suggestions. (day2dayparenting.com)