May 23, 2000 -- The unflattering "waddle" often associated with a pregnant woman's gait appears to be no more than a myth, according to new research. Although investigators have found that women walk the same way before and during pregnancy, the changes in their body mass and distribution do leave them at increased risk for low back, hip, and calf pain due to overuse.
"With big changes in body weight and distribution, regular exercise prevents joint wear and tear, especially in the pelvis, hips, and ankles," says study author Theresa Foti, PhD, a kinesiologist at Shriners Hospital for Children in Greenville, S.C.
Foti explored gait patterns in 15 women between the ages of 25 and 38 during their final weeks of pregnancy. Participants were videotaped walking across a room, and their strides were compared using motion analysis software. The process was repeated a year later for all but two participants, who were tested prior to pregnancy.
Overall, gait patterns were remarkably unchanged during pregnancy. There was no evidence of a waddling gait, but there were significant increases in hip and ankle forces, indicating that muscles and joints compensate for changes in body mass. These adjustments allow for a normal stride but place muscles and joints at high risk for overuse injuries, particularly among inactive women. The research was published in the current issue of The Journal of Bone and Joint Surgery.
Fortunately, exercise helps prevent overuse injuries and has many other benefits as well. "Most physicians now recommend mild to moderate exercise during pregnancy, even for women who didn't exercise previously," says Michael Lindsey, MD, director of maternal/fetal medicine at Emory University Hospital and associate professor of obstetrics/gynecology at Emory University School of Medicine, both in Atlanta.
Regular exercise is associated with shorter labor and faster postpartum recovery, although safety remains an important consideration. "Maintaining a basic level of fitness is fine, but pregnancy is not the time for vigorous exercise or weight loss," adds Lindsey. "After the first trimester, I also advise against sit-ups and weight training, particularly in women at risk for preterm labor."
But low-impact exercise offsets hormonal changes that weaken the joints. "During pregnancy, the body secretes relaxin to widen the birth canal, but it loosens up all the other joints too," says Lisa Stone, deputy director of the Georgia Commission on Physical Fitness and Sports and founder of "Fit for 2," an exercise program designed for expectant mothers.
Stone, who is certified as a pre- and postnatal fitness instructor by the American Council on Exercise, tells WebMD that strengthening exercise stabilizes the joints and stretching exercise prevents muscle strains. Aerobic exercise, a third Fit for 2 component, burns fat and holds weight gain to a healthy maximum of 25-35 pounds.
Pregnant women should also drink plenty of water before, during, and after exercise. "Unlike you, your baby can't sweat to prevent overheating," says Stone. "So it's a good idea to take a swig of water every 10-15 minutes. Another rule of thumb is to stop exercise well before the point of exhaustion."
"I was running five miles a day until I became pregnant, but I had to stop because it was too uncomfortable," says first-time mother Shannon Powers-Jones, a freelance writer in Atlanta, who adds that exercise helped improve her psychological health.
- Low back, hip, and calf pain often experienced during pregnancy can be prevented with stretching, strengthening, and aerobic exercise.
- In compensating for changes in body weight and distribution, regular exercise helps prevent overuse injuries, particularly in the pelvis, hips, and ankles.
- Exercise offsets hormonal changes that weaken the joints, but sit-ups and weight training should be avoided after the first trimester, particularly in women at risk for preterm labor.