With Yassos, you run 10 x 800s. With Fultzy’s, as we’ll call them, you run 20 x 400. And the time you can maintain for those 400s (let’s say 1 minute, 45 seconds) is the time you should be able to run in your half marathon. Only it will be one hour and 45 minutes.
“I prescribe a 200-meter recovery jog/walk between the 400s,” says Fultz. “That’s typically 60 to 90 seconds, depending on the runner.”
Be sure to note that your goal pace is not the 1:45s you were running for 400 meters in practice, which is equivalent to 7 minute pace, or about 1:32 for a half marathon. Instead you want to dial into the pace that will get you to the half-marathon finish in 1:45. And that pace is about 8:00
Fultz, the 1976 Boston Marathon winner, has trained thousands of runners for the Dana Farber Marathon Team. He’s probably one of the biggest proponents alive for even-split pacing in distance races. Or even negative splits. “There’s a pretty solid rule of thumb about what happens when you go out too fast,” he notes. “For every second/mile that you run too fast in the first half, you’ll lose three to four seconds/mile in the second half.”
That can add up fast. For example, if you run 10 seconds/mile too fast over the first half of a half marathon (that is 60 to 70 seconds total), you’ll lose 3 to 4 minutes over the second half. Ouch!
To avoid this, according to Fultz, you can gauge your fitness by running the 20 x 400 workout in training, and then adjust your race day pace accordingly. In the early miles of your half marathon, make sure you go no faster than your goal pace. If you’re feeling strong toward the end, go ahead: Pick it up. But don’t do that at the front end of your race.