Conventional wisdom says that a smooth pedal stroke makes you faster.
But we've seen studies arguing that it's the other way around: Fitness contributes to better pedaling technique. The fitter and stronger you become, the easier it is to pedal smoothly at a given intensity.
The bottom line, though, is that a smooth and supple stroke increases your efficiency -- more so the longer the ride. It's the mark of an accomplished roadie, too. The French even have a word for it, souplesse.
Here's one good drill to help you pedal better at any intensity level:
Mentally divide your stroke into three parts:
1. Power the pedal down
2. Pull through at the bottom like you're scraping mud off the sole of your shoe
3. Pull your knee forward over the top like you're aiming it at the handlebar
To work on each part, concentrate on one of them every five pedal strokes.
For example, to improve your downstroke, give the pedal a little kick as the crankarm goes forward from vertical to horizontal. Do this with the right leg, pedal normally five stokes, then do it with the left leg.
After couple of minutes, add similar emphasis to scraping the pedal through the bottom. Finally, accentuate pulling over the top.
Do this drill up a steady mild grade, on the flat using a big gear, or against the wind (another benefit of headwinds). The idea is to have enough resistance to slow your pedaling so you can isolate the three stroke phases.
Make this drill part of every ride. Before long, you'll notice a difference in the smoothness and power of your whole stroke at normal cadences.