A study involved 151 infants, 4 to 6 months of age, divided into two groups; 121 back-sleepers and 30 stomach-sleepers. The infants were tested for motor development according to two developmental scales systems. The scientists found that 22% of the 6 month old back-sleepers were behind in their motor skills. 75% of the babies in the trial received less than 20 minutes a day of tummy time.
The study found that there is a relationship between back-sleepers and lower motor skills. Babies who were the least exposed to tummy time tended to be the most delayed in their motor development skills such as: rolling over, touching their toes and sitting unsupported.
Babies should be put to sleep on their backs to reduce the risk of sudden infant death syndrome (SIDS). Please don't forget the tummy time!
Johnson K, "Is 'Back to Sleep' Slowing Motor Development?" Family Practice News, February 15, 2004:44.