Just like swimmers practice their stroke and golfers practice their swing, cyclists need to work on improving their pedaling mechanics through drills.
The idea is to learn to use less energy by pedaling more efficiently or economically. We want to emphasize this during early-season training, but should maintain it throughout the year.
What follows are the specifics of efficient pedaling mechanics and descriptions of drills designed to help you improve your technique.
Specific Mechanics of Efficient Pedaling
Start with a sturdy platform: Pedals and shoes should transfer power to the pedals, not take it away. A large pedal surface to push against, and a stiff shoe, works better than a small pedal that allows your foot to rock back and forth, or shoes that flex under pedaling loads. Excessive float can create problems too. Think about doing squats while standing on blocks of ice.
Align your knee over your pedal: A knee that moves in or out will reduce pedaling effectiveness and rob you of power. I recently had Andy Pruitt of the Boulder Center for Sports Medicine perform a 3D cycling biomechanics analysis for me. Andy showed me how my feet rolled over and my knees wandered a bit. After moving my cleats to the side, and placing small (1.5-degree) wedges under them, I was able to keep my knees over the pedals.
Push the pedals over, or across, the top of the pedal circle: This creates a longer power stroke by starting force application before the down stroke begins.
Apply force in a direction that is 90 degrees to the crank arm: At the top of the pedal stroke (12 o'clock) you should be moving the pedal forward. At 6 o'clock move the pedal backwards. The only time you should be pushing directly down on the pedal is at exactly 3 o'clock. At 2 or 4 you'd be moving the pedal slightly forward and down, or slightly back and down respectively.
Pull through the bottom of the pedal stroke: This will assist in keeping a constant force throughout the entire pedaling circle and help the leg that's moving the pedal up over the top of the stroke.
Unweight the pedal as it is coming up: A leg that is resting on the rising pedal creates more resistance for the leg pushing down to overcome. It's not necessary to pull up on the pedal, just unweight it. Try lifting your knee like you're stepping up onto a box.
Focus on one portion of the pedal stroke at a time and you'll be able to improve it more quickly. Then gradually piece them all together as one cohesive movement.