I like to think I'm in decent shape and will even go as far as to say I'm a runner—not a jogger. So, I was thrilled to hear about a class at my gym that didn't involve coordination or rhythm—traits I've never had and am not ashamed to admit.

Having already completed a steamy, June morning run, I confidently strolled to class thinking to myself, air conditioning, how bad can it be? There were about seven people in the class, all of whom seemed perfectly "normal"—meaning no body builders or miniature aerobics instructors—I was in stride with the rest of the group.

The instructor, Stacey (a tiny, toned, new mother to boot) started us off immediately with a warm-up that consisted of jogging in a wide circle around the room. She announced that we'd be doing every "circuit" for one-minute intervals before switching routines. After an easy warm-up we quickly moved to a side-to-side step, "stay low, abs in tight, move fast" coached Stacey. I liked this move, felt my inner thighs working and thought it would be a great complement to running.

Still feeling strong. Next came the "speed skating" maneuver followed by an in-place simulated bicycle hill climb. I couldn't believe it but I actually enjoyed this even while feeling the burn! I couldn't quite seem to get the karaoke side step under control (turning my legs into a pretzel) but it was only for a minute, so I just faked it. Then came the jumping jacks, squats, high jump leap and "wall sit." At this point, I was visibly tired and dripping with sweat and it had only been 25 minutes. Thinking the class was coming to a close, I breathed a shameless sigh of relief when Stacey turned down the music and had us drop to the floor for push-ups—and not the girly ones.

I silently took comfort in the fact that my classmates were looking as bedraggled as I was—or else sweat had clouded my contacts—as Stacey had us line up against the wall for what she called the final "suicide" round. As I was quickly getting over my smug runner self, we embarked on sprints. The cool down was a combination of crunches and Pilates; every muscle was spent.

Despite the flashbacks to high school field hockey practice, the Sports Circuit is a great way to enhance my running and I'm convinced that if I make it part of my regular routine, I'll be running faster and stronger in no time. Or maybe I'm just a glutton for punishment—I'll let you know.

— Lydia Pelliccia