Even if you live in a completely flat area, when you’re riding outside you inevitably have the opportunity to coast every now and again to give yourself a bit of a break. That doesn’t happen during indoor rides.
The consistent effort is one of the factors that make indoor training more efficient. Like running on a track or riding in a velodrome, the conditions are also very consistent, allowing you the opportunity to do test sets and gauge your progress.
Top American Ironman Champion Andy Potts finds his strategic indoor training works so well, he only rides outside during races. Surprisingly, he’s hardly alone on the pro front when it comes to almost-exclusive indoor training. Meredith Kessler is another multiple-IRONMAN champ who mixes indoor with outdoor rides. Much of Kessler’s training is done while teaching indoor classes in San Francisco.