When moms want to exercise, they typically have two choices: Get someone to baby-sit while they workout, or find ways to exercise with their children. Gyms with nurseries are one way they can pull this off, but the cost and complexity of getting children to the health club is a barrier for many women.

When All Else Fails, Improvise

A more practical approach is to find creative ways to be physically active with your child, says Schmitz, whose favorite exercise program--when she was pregnant with her second child--was the "King and I" workout with her then 19-month-old son, Mack.

He was crazy about the song, "Shall We Dance." So Schmitz played it over and over while waltzing around her living room holding the 27-pound toddler. "I got pretty winded, but we had lots of fun," says Schmitz. Early in her pregnancy, Schmitz waltzed Mack to the four-minute song at least eight times during the course of the day. Near the end of her pregnancy, she was down to about three or four daily dances.

Another of her kid-based workouts is "getting wild and wacky at the playground," she says. This involves chasing Mack through the slides and finding other playful ways to keep moving with him.