I think, if you'll pardon the pun, that you're ont he right track.

Your total training distance for this workout should be about five miles. This distance includes your warmup and cooldown, each of which should be about a mile and a half (six laps). Your warmup can consist of a slow jog, gradually increasing pace until you're moving at a reasonable pace. You shouldn't be running all out at the end of your warmup, but you should be at a point where you're not accelerating too much to hit your target pace.You should do the reverse for your cooldown; gradually slow down until you're at a slow jog/walk by the end.

Your interval sessions should be three 800m (half-mile, or two laps around the track) runs at a 5:21 min/mile (?! You must be really fast!) pace. Each of these interval session should be separated by a 400m (quarter-mile, or one lap around the track) walk or jog so you can recover a little bit for the next run. It looks to me like you're doing about 1.5 miles of speed intervals with a half mile of recovery jogs.

I think you've pretty much got it right.

If you're looking for another three-day-a-week plan, you should take a look at the Furman Institute for Running and Scientific Training plans. There are modified versions of the half-marathon and marathon plans available at runnersworld.com. They're based on three runs per week plus two days of cross-training. If you're honest about your previous race performances, then you should end up with a training plan that will push you but shouldn't lead to injury.

Good luck!

Don

Good catch, spicegeek. I missed that little detail.

Speedwork puts a lot of stress on your body. The general rule of thumb is to wait until you've hit about 20 miles per week consistently for a few months before diving into speedwork. This level of intensity very much increases your likelihood of overuse injuries if your body isn't comfortable taking a beating.

Increasing distance is, for the time being, the best way to improve your endurance, speed, and resistance to injury. I'd strongly recommend you take a look at the Hal Higdon novice plans for whatever distance you're looking to race.

Don