I trained for my first 1/2 Ironman completely on a spin bike (along with running/swimming) since my current bike (a Cervelo) didn't arrive on my doorstep until the week before the race. I took 4 spin classes a week, 1 hour at a time, and proceeded a couple of the classes with fast transition runs on the treadmill. My bike split with solely spin miles has proven to be just as fast (if not faster) than when I do a bunch of road miles. I think the benefit lies in that it is a continuous workout (no stoplights or dilly dally) and when taken seriously, my heartrate stays up around my anaerobic threshold for the full hour. To this day, I only ride the roads once a week...even when preparing for Ironman...and I have been pretty successful with this approach to my bike training. Healthy trails, Kim Brown, MS, RD Sports Nutritionist
www.kbnutrition.com
Kim Mueller, MS, RD
Sports Nutritionist
http://www.kbnutrition.com