I got this out of Sept 2006 issue of Runners World Magazine. (This is a great issue, so go pick up a copy at the newsstand!)
“Yasso 800s are a good way to guage your fitness level during marathon training and help predict your finishing time. The key is to build up to running 10×800 meters with a 400 meter recovery between each repeat. You need to do at least two of these sessions three to five weeks before the marathon. If you’re able to run your 800s in 0:03:30, you’re in shape to run a 3:30 marathon. For many people, the correlation is spot on. Do these workouts midweek, say, on Wednesday, when you’ve done your long run on the weekend. If you run your 800s on totally fresh legs, you’ll do them a heck of a lot faster.”
I’m running a 1/2 marathon in three weeks. My 1/2 marathon goal is 1:55, which is an 8:45 pace. I’m assuming that if I cut this formula in half, it will give me a similar prediction. I can do 5x800s with each being about 0:03:38. So, I should be able to do a 1/2 marathon in half that time, which is 1:49…right?
Here’s a really neat tool to predict race times based on past race performance:
http://tinyurl.com/l9lf9
According to that tool, I should be able to do a 1/2 marathon in 1:51:33.
I’ll post back after my race whether these predictions worked. The race is on Sept 3rd… Wish me luck!