Last year I tried to the ING Atlanta Marathon and did not make it.  This year I am planning to run the half that day instead.  Below is the training schedule I plan to use.  It is from Runner’s World and slightly modified to fit my weekly schedule.

Aerobic Intervals (AI): You push the pace. But just a little. Find a tempo that feels somewhere between comfortable and “Hey, I’m workin’ a little here.” Don’t run this too hard. Trying to add too much intensity while you’re also increasing mileage spells I-N-J-U-R-Y. When you finish the timed AI, jog very slowly until your breathing returns to normal, then work back into your regular pace. On all other days, just run your assigned miles as you feel.

Gentle Pickups (GP): At the end of your run, walk for several minutes, then slowly increase your leg turnover on a flat stretch for 100 meters–the straightaway on a track–up to the point where you start to breathe hard. Hold it there for 10 to 20 meters, then gradually slow down. Walk to full recovery before you start the next one.

The purpose of both AI and GP is to improve your stamina, leg speed, running efficiency, and to make your normal pace feel more comfortable. What’s more, this kind of up-tempo running adds variety to your training. Always a good thing.