I'm a former gymnast (waaayyy former... like when dinosaurs roamed the earth) who let himself get heavy for years. I've lost close to 100 lbs now and am back in shape but my training had been pretty much confined to weights and cardio in the gym. Cardio in the gym got really boring, so I bought a bike about a year ago. It's just a Trek hybrid. Nothing fancy. But I've been loving it. I now commute to work (about 12 miles each way) 2-3 days a week, weather premitting, and ride 20+ miles at least one day each weekend.