A recent article in the April 2012 edition of Runner's World magazine, entitled "Go Short: Drop down in distance to ramp up speed and power," claims that: "But to run [their] best...top pros, whether they're milers or marathoners, spend time each year racing under-distance." I was thrilled to hear this news (for I take a similar approach in my own training)! Indeed, the article continues, stating that: "Training for short races speeds up your cadence and increases the power of your push-off, making you more efficient and ultimately faster when you move back to longer distances." This, for me, is old news. Some might call this one of the oldest tricks in the book: get your body used to a very intense speed for short distances, and you will feel like you are gliding when you run more moderate speeds for a longer duration. But, to my knowledge, few ultramarathoners have been apt to apply this old nugget of wisdom to their training. Notice that, even in the runner's world article as quoted above, ultrarunning pros are not mentioned. This is due, in part, to the fact that Runner's World is geared more toward mainstream running events and less toward the obscure ultra races that take runners through the woods for dozens of miles. Even so, magazines that are geared more toward ultrarunning -- such as Ultrarunning Magazine, the Running Times, and Trail Runner -- fail to make note of this important method of training. So, in general, I think that the "go short" training plan is utilized to a lesser degree in ultra training.
But this method is equally as effective for longer distances. In fact, it might be even more effective for ultrarunning pros who stick to the trails (rather than the pavement). Many prominent ultraraces, like the Western States 100, the Hardrock 100, the Leadville 100, and the Wasatch 100, feature some of the most rugged, technical running trails in the world. They are some of the most rugged and technical in the sense that the trails are extremely steep, full of rocks, roots, river crossings, and often muddy or unkempt. Thus, it is necessary to "pick through" the trails, so to speak, by shortening one's stride in an effort to avoid the sharp rocks, the bulky roots, or the mud puddles. A prominent way, and perhaps the most effective way, to develop a short, efficient stride, is through speed work. As the Runner's World article notes, speed work for shorter distances "speeds up your cadence and increases the power of your push-off." In other words, it makes your stride more efficient. When running 50 miles, or 100k, or 100 miles, the more efficient your stride, the less energy you expend, the more likely you are to perform well later in the race. The point is that you want the most efficient stride possible. Speed work provides this. Even as an ultrarunner, it can be beneficial to incorporate intervals as short as 200 meters (yes, meters!) into a training program. I know several ultrarunners (myself included) who routinely run 200 meter repeats. The benefits of speed work remain the same for any distance where you can run at a substantially faster pace than your projected race pace (I'm thinking here of anything from 200 meters to 2 miles): you speed up your cadence and increase the power of your stride.
And the benefits of speed training are more than just physical: a runner also benefits mentally. The RW article quotes Chris Solinsky, the first American to break 27 minutes in the 10k, as saying that: "If you're too ingrained in longer distances, you get scared and think that's as fast as you can go." For an ultrarunner, a psychological benefit is as good as gold. So, I say, train short to go longer, faster!