You join a swing dance class, and at first you’re all left feet. But – slowly, eyes glued to the teacher – you pick up a step or two and start to feel the rhythm of the big band beat. A good start.

Two neighborhood moms looking for a workout buddy found a passion — and a friendship — in dance. Now, they teach other moms to groove, one shuffle at a time. Anna Blanc, 42, and Christina Reynolds, 38 ...