Practice Climbing
You don’t necessarily have to train on big mountains to gain climbing fitness, but it does help to practice riding big climbs. There are several reasons. First, you can’t coast going up a steep hill. Not even a few seconds.
This may not seem like a big deal, but if you are accustomed to coasting for a moment while you reach down for that water bottle, surprise – you’ll fall over if you try this on Mount Washington. This British Global Cycling Network video explains a lot:
It may not be as easy as you think. Throw in fatigue and 50mph wind, and you have a real challenge on your hands. Since you can’t coast, you can’t rest either.
You’ll be slurping that sports drink into your lungs if you don’t practice drinking when your heart is pounding out of your throat. Another reason to practice long, steep climbs is to learn what cadence you climb most efficiently at. This may be slower than your optimal or preferred cadence on flat terrain.
There are various reasons for this. One being that because you are going so slow, you have very little momentum. The force of gravity actually slows you down between pedal downstrokes. Thus your speed accelerates appreciably with each pedal stroke. This is quite different from cruising at 25 mph where your speed is very nearly constant over each pedal stroke.