6 x :10 fast/:50 easy
Bikes are incredible traing tools. You can use them to train for a variety of goals, and they work great for speed training. You'll need an indoor, fixed gear (doesn't freewheel, pedals keep turning even if you let up) spinning-style bike to get the most out of this workout. Make sure you use the toe straps or clip-in pedals.
Warm up for 15 minutes or so, mostly in Zone 1-2 with a few pickups toward the end. Nothing fancy.
The main set, however, is quite challenging. Set the bike at a moderate resistance according to your ability level. The first 10 seconds of every minute is all-out. Ramp up for 2-3 seconds, hit your fastest cadence, and then ease out of it at 10 seconds, turning the cranks slowly to recover for the remaining 50 seconds of the minute. Then go again. You are looking for a cadence of 120-160 rpm's per minute. This is on the edge of control for most athletes.
We don't want to push a big gear and grind slower. That's power training. This is speed. Cadence is king.
Spin it out for 10-30 minutes after.