Do Speed Training

Old CW: Speed is for sprinters.
New CW: Speed training helps everyone.

Think back on your past week of running. How much of it was at a brisk, saber-tooth–eluding clip? Today's top runners do as much as 20 percent of their training at speeds faster than race pace. This conditions the fast-twitch muscle fibers that are seldom recruited during slower running. It also maximizes aerobic capacity (the rate at which your muscles use oxygen) and increases stride power and efficiency.

Speed training also makes you ripped.

You burn more calories, because, simply, it takes more energy to run hard. And fast running is the perfect companion to strength training—both work the fast-twitch muscle fibers. Here's a speed-training format to try.

The Ladder
Do this workout at a running track.

1. Warm up with 5 to 10 minutes of easy jogging, followed by stretches for the hamstrings and calves.
2. Run one lap hard, then jog one lap.
3. Run two laps hard and jog one.
4. Run three laps hard and jog one.
5. Optional: Run four laps hard.
6. Cool down with 5 to 10 minutes of easy jogging.

http://www.menshealth.com/mhlists/running_efficiently/Do_Speed_Training.php