Is a good stride a matter of many disparate elements coming together or one underlying virtue?
Running form is still a hot topic these days. Countless articles about running form have been printed and posted within the past couple of years, long threads on form keep appearing in online running forums, experts on running form are touring the country talking about it, whole books on running form have lately hit the presses, and running coaches all over the country are now teaching running form, whereas in the past they ignored it.
With all this communication going on, we must have a very clear idea of what good running form is, right? Not really. In fact, all of this communication about running form is going on precisely because we don’t yet have a clear idea of its proper definition. If we’d figured it out we would have fallen silent on the topic and moved on to another.
If you ask any given “expert” on running form what it is, you’ll likely get a response that consists of a laundry list of seemingly unrelated characteristics: a midfoot or forefoot footstrike, a slight forward lean, relaxed shoulders, eyes focused straight ahead, and so forth. To improve your running form, you must instill each of these characteristics in your stride. They will somehow add up to speed and efficiency.
Perhaps it’s the Plato in me, but intuition has always told me that, whatever it is, good running form must be a single thing, not a grab bag of things. And if you take a close look at the research on running form, you will find some pretty solid evidence that good running form may indeed be one single thing.
My current favorite researcher on running form is Stephen McGregor at Eastern Michigan University. McGregor uses three-dimensional accelerometers to measure various stride characteristics and plot them against running economy, as measured the old-fashioned way, through oxygen consumption in relation to velocity. In four years, McGregor has found only one stride characteristic that truly matters with respect to running economy: sagittal plane accelerations. In plain English, McGregor has found that the most economical runners slow down the least between strides, and the least economical runners slow down the most.
Other researchers have arrived at more or less the same place from different entry points. In a 2007 study, Finnish scientists measured a long list of stride characteristics in 25 trained endurance athletes and plotted these against running economy and maximum running speed. They discovered that only one stride characteristic was closely associated with both economy and maximum speed: ground contact time. The less time a given runner’s foot spent in contact with the ground, the more economical–and faster–he was.
A short ground contact time and minimal sagittal plane deceleration are more or less the same virtue. Or, perhaps better put, they are different ways of measuring the same virtue. The quicker you’re able to get your foot off the ground, the less you will decelerate. And the less you “hit the brakes” when your foot lands, the less time your foot will spend in contact with the ground. Short ground contact time and minimal sagittal plane deceleration are sort of like high club head speed and long driving distance in golf.
Now, a running form expert with a conventional perspective might grant that this virtue of short ground contact time/minimal sagittal plane deceleration (SGCT/MSPD) is the be-all and end-all of good running form, but he will likely say that this virtue is achieved through the usual assortment of good technique elements: midfoot or forefoot landing, slight forward lean, etc. He will say that these elements came first and have added up to speed and efficiency.
But the evidence suggests that this is not the case. The relationship between SGCT/MSPD and performance is much stronger than the relationship between the standard elements of good technique and SGCT/MSPD. In other words, you absolutely must have SGCT/MSPD to be fast and economical, but you don’t necessarily have to have a forward lean or a forefoot footstrike to have SGCT/MSPD. True, most runners with SGCT/MSPD will exhibit this characteristic, but not nearly all. The late Sammy Wanjiru, for example, leaned backward, not forward, when he ran. And 2009 New York City Marathon winner Meb Keflezighi is a heel striker. (see video below)
I don’t think runners arrive at SGCT/MSPD and high running economy and speed by adopting the various individual elements of good running technique. I think they reduce their ground contact time and deceleration simply by trying really hard to keep running fast despite mounting fatigue in training, day after day, week after week, month after month, and year after year. This repetitive exertion of will stimulates an unconscious evolutionary process whereby the runner’s neuromuscular system gradually figures out how to move his unique body to generate more speed with greater efficiency.
Here’s where I really step into the realm of speculation, but I also believe (or suspect) that the reason we don’t all start off in possession of the one great virtue of good running form is that we’re lazy. There is a part of us that doesn’t want to run—that never wants to run. When you do run, each landing of your foot represents an opportunity to rest. Most of us take that opportunity to a greater extent than is good for our running performance. We land—pause—and then push off. The best runners don’t really do that. They don’t let themselves rest when a foot hits they ground. Instead they bounce off it like they’re tossing a hot potato and catch their rest in midair.
It’s hard to think of an analogy. The best I can come up with is the way we pick up heavy objects from the ground. The most effective way to do it is, of course, to squat down and use the legs, but this technique is seldom instinctual. It usually has to be learned the hard way. Why? Because we’re lazy. It takes a smaller initial investment of energy to bend over from the waist and try to do the work exclusively with the smaller muscles of the upper body.
Running is kind of like that. The ground is very tempting. Your foot wants to hang out there a while. To the beginner it seems (unconsciously) a little easier to land—pause—and then push off than to essentially refuse the ground’s embrace—to strike it, thrust it away, be done with it. But that extra investment of effort up front saves energy in the long run. Most runners make little progress in overcoming their laziness. Those who make the most progress become the best runners.
It is interesting that, in the latter miles of a long race, even the very best runners see their ground contact times and sagittal plane decelerations increase. As they fatigue, the part of them that doesn’t want to run starts to gain the upper hand. That’s exactly what fatigue is: the athlete’s rising refusal to keep running.
Runners improve their form by reducing their ground contact times and sagittal plane decelerations, and they do that by encountering these moments of rising refusal and resisting them with everything they’ve got. We do not become better runners by emulating some Platonic ideal of good form. We become better runners by not letting ourselves be lazy—by pushing back against the pain with good old-fashioned willpower. When we do that, the details take care of themselves.