One thing Philadelphia doesn 't have: Soul Cycle, the Zumbameets-meets-spinning classes that are sweeping New York. In its place is Body Cycle, which opened 15 months ago in the Rittenhouse Square area and is the only studio in the city dedicated to indoor cycling. People of all ages and fitness levels can do Body Cycle's high-cardio, lowimpact, heart-thumping, sweatinducing spinning. The music, the lighting, the vibe: it's a great workout that burns 400 to 800 calories in one, 50-minute class. Bikes can be modified for beginners and to accommodate lower back issues. "It's fun and addictive the way that Zumba is," says Judy Cohen, a 57-year-old who has become a Body Cycle enthusiast. "It's very high energy, so it holds your attention and it really works your entire body. I go home sore, but happy."Here's another challenge: finding time to exercise while taking care of young children. Luckily, there are plenty of things that fitness-minded parents and grandparents can do with their toddlers. The Philadelphia Gymnastics Center in West Conshohocken offers a You & Me class. "It used to be 'Mommy & Me,' but now the kids come with daddies, nannies, grandparents and even a few aunts, so we changed it to 'You & Me,' " says Jacquelyn Bier, the owner and director of the center.Adorable is great. Inner peace might be even better. Wes Tudor, owner of Rittenhouse Square's new Raja Yoga, introduced a twist on traditional Mommy & Me classes. Raja's class is for kids ages 1 to 4 and the adults who want to bond with them through yoga. "Some classes focus on incorporating the child into the adult's yoga practice," Tudor says. "This is tailored more toward the children. It's a creative playtime with a yoga theme. We don't even use mats. The kids and their adults get in a circle and do animal poses, fun songs and stretches. Then, we'll do special things like the adults making a downward dog tunnel and the kids crawling or running under it."