Indoor vs. Outdoor Miles

Every winter on the bikejournal.com forums, someone posts a question or two about riding a stationary bike or doing workouts on a trainer while they wait for better outdoor biking weather. Immediately, the biking world is split into two groups: the indoor defenders and the outdoor purists. This argument tends to sound like the "support the troops" arguers and the "Iraq war decision was bad". In other words the argument isn't a true dichotomy.

The indoor defenders will argue that you're tracking your own workouts on bikejournal.com and that whatever you'd like to track is fine. Besides, stationary bike riding is so boring that it's impossible to log as many miles indoors as you would outdoors, even though weather is no longer a factor indoors. I'd also add that there's no ability to coast the bike or make comfortable changes in positions to climb, descend, sprint, or turn. Add that to the constant resistance of the trainer, and it's actually harder to ride for an hour on a trainer than it is outdoors.

The purists believe that cycling can only be done outdoors with the bike in actual motion. The fact that you can't go up a hill indoors immediately disqualifies any indoor miles. You can't possibly simulate hills, wind resistance, changing road quality, and good scenery indoors. Besides, a trainer gives you the ability to cycle 24 hours a day, whereas the winter elements only give you an 8 hour window to ride in. Also, a purist will actually go out and brave the elements (we question whether or not the elements are in Arizona or Florida) rather than wimp out and ride indoors.

What I've done below is try to give a realistic comparison of indoor vs. outdoor miles so that folks can make a proper decision on whether or not they can be considered equivalent.

Category	Outdoor Riding	Indoor Riding
Effort	Hills & Wind	Harder Gears & Resistance
Food	can only carry so much before you have to stop and buy more	you can put the trainer within reach of the fridge
Draft	If you ride with a buddy, you help each other go faster with a draft	draft position not recommended due to risk of farting
Music	If someone in the pack can sing, you'll have some music	IPod, stereo, radio, TV, and orchestra are all options
Entertainment	I've heard that some cyclists can juggle while riding	TV, DVD, computer, books, magazines....
Scenery	The sky is the limit. The more you ride, the more the scenery changes. You can stop and smell the roses.	Can only change scenery if you have one of those photo album screen savers. Quite stinky unless you have a rose-flavored Glade plug-in.
Injury Risk	There's cars, cracks, rocks, and other cyclists that can take you down. You may find emergency response slow if you're out in the middle of nowhere.	911 on a land-line available, but you probably wouldn't want to deal with the embarrassment of hurting yourself while riding a trainer.