Figured I'd do a quick but excruciating little form of torture called Tabata. It can be done with almost anything....bike, rower, sprints, squats....but I choose my spin bike.With those of you not familiar, its a short warm-up followed by all out sprints for 20 seconds followed by only 10 sec. recoveries. You do sets of 8 (4 mins.) spin a little and then repeat 3 more times. Doesn't sound like much does it? Try it some time. Also threw in 5 sets of 50 decline bench sit-ups with a 25 lb. plate on my chest. That finished me off.