Jul 15, 2013 11:57 AM EDT By Cary Carr
According to new research, biomechanical changes that happen during pregnancy can affect a woman's running stride, The New York Times reported.
In a study published in the journal BMC Pregnancy and Childbirth in March, researchers documented that women's walking strides grew wider and shorter during their pregnancy terms, leading them to "waddle."
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While there is minimal research on how exactly pregnancy can affect a woman's running form, which may be due to the lack of women who run during their pregnancies, strong evidence that running during pregnancy doesn't harm a women's fetus, more attention is being given to the topic.
Plus, with marathoners like Kara Goucher and Paula Radcliffe, who trained during their pregnancies and returned to competition after giving birth, women may be less hesitant to hit the pavement.
A study published in The Journal of Orthopedic & Sports Physical Therapy also showed the biomechnical changes in a pregnant runner's body. One case, a 27-year-old- runner, began to see her pelvis increasingly tilt forward as her pregnancy progressed, and six months postpartum, the tilt remained.
Also, the runner displayed more side-to-side pelvic motion while running than she had before her pregnancy. Even a year after her last pregnancy, her right leg struck the ground harder than the left, absorbing more force with each stride.
"None of this was surprising," Dr. Bryan Heiderscheit, a professor of orthopedics and rehabilitation, said. "Pregnancy and labor stretch the muscles and connective tissues in the abdomen," which, in turn, allows the pelvis to tilt and sway. So unless a woman strengthens those affected muscles after giving birth, the tissues stay stretched."
Dr. Heiderscheit advises women to pull the belly up and in multiple times by "imagining that you're trying to cut off the flow of urine."
"I think it's time we acknowledge that having a baby is going to change how you run," Dr. Heiderscheit said.