Johanna Darrah, a professor of physical therapy in the Faculty of Rehabilitation Medicine, says infants develop the ability to roll much the same today as they did 20 years ago when the "back to sleep" campaign was introduced and successfully reduced the occurrence of SIDS. Her research answers fears that the back to sleep campaign, which recommends putting babies to bed on their back instead of their stomach, would hurt an infant's gross motor development, specifically the ability to roll from tummy to back and vice versa.

"Infant gross motor development hasn't changed that much in 20 years," says Darrah. "The thought that babies first roll from their tummy to their back, before they go from their back to their tummy, does not appear to be the case. For most babies, they happen very close together."

Darrah first studied infant motor development in the early 1990s as a graduate student of former dean Martha Cook Piper when the pair published the Alberta Infant Motor Scale, an observational assessment scale used throughout the world to measure infant motor skill development from birth to walking.

More than 20 years later, Darrah revisited the work, studying the rolling abilities and motor skills development of 725 Canadian infants ranging in age from one week to eight months. One of her goals was to see whether the norms identified and developed 20 years ago still represent the age of emergence of gross motor skills.

Darah notes there is some concern in the physical therapy community that babies develop movement skills like rolling from tummy to back at later ages because of reduced time spent on their stomachs. Those concerns appear to be unfounded, she says, explaining that her results are particularly valuable for health-care practitioners specializing in early childhood development.

"Our results would suggest that gross motor skills emerge in the same order and at the same ages as 20 years ago. The environment is of course important to gross motor development, but the change in a sleeping position hasn't made much difference as to when babies roll from stomach to back."