Put a little spring in your step – literally – with these running form tips.
Written By: Alan Couzens, MS
In my last article I compared Bruce Lee’s one-inch punch with the running foot strike to highlight the importance of the rapid application of force, i.e. power, to distance running. But the effectiveness of this powerful “ground strike” is largely contingent on the body being appropriately positioned to allow for maximal elastic recoil within the running stride. I only briefly mentioned this important factor in that first article. I will address it in depth here.
Picture bouncing on a pogo stick. The harder you load the spring, the more the spring will recoil and the further into the air it will send you. Now suppose you have a prankster friend who decides to take the spring out of your pogo stick. What will happen when you hop on and attempt to jump down hard on the stick? Not only will you get a back-breaking jolt sent up through your body, you also won’t jump very high. In fact, had you known about your friend’s fiendish plot, in the interests of safety, you would have probably opted for tiny little jumps with less of an interest in loading your stick and more of an interest being efficient by staying close to the ground. The same is true with running; there is a lot of benefit to using your “springs”, i.e. your muscles and tendons, to aid forward propulsion. However, if your body is not in the right position to use these springs most effectively, all you’ll get by attempting to “hit it hard” (on- inch punch style) is a jolt up your spine and some very inefficient propulsion.
So, in the interests of safety (and because you never know when your buddy is going to pull the springs from your pogo stick), maybe we should just play it safe and stick to shuffling close to the ground. The downside of this strategy is the loss of potential free speed that our tendons are able to gather on each foot strike. So, this brings us to the important question: How much benefit can we expect from using our springs?
Teasing out all of the various contributors to running economy in an effort to determine the relative benefit of a particular technique, or a given runner’s form, is a tough task. There is a complex interplay between physiological and mechanical contributors that makes true conclusions about the quantitative benefits of a given running technique hard to determine. However, a very simple indication of the benefits of using your springs versus not using them can be seen if we compare the oxygen cost of trained runners when walking versus running. See below:
Kram and Taylor (1990) found the above relationship between walking and running energy costs at various speeds. If we compare walking (a heel strike activity in which the tendons are unloaded) versus running (a mid/forefoot activity in which the tendons are rapidly and fully loaded), even at slow jogging speeds of ~2.5m/s, individuals can expect to use 10 percent less energy than walking at a comparable speed. As speed increases, running economy actually improves as the springs are loaded more and more with progressively more forceful and rapid muscular contractions.
Clearly, even at typical Ironman paces, there is advantage to holding true running form versus the hybrid walk-jog we commonly see where the runner never really leaves the ground. And at typical marathon paces, even at the back of the pack, there is a huge difference in energy cost between the upright, hands-forward-of-the-body, heel-striking, “walker in fast forward” versus the compact, hands-on-the-midline, slight-forward-lean runner who has a clear (though brief) float phase in every stride.
Let’s look at these differences in a little more detail.
In the first case, the runner:
- Lands with the foot in front of the body
- Claws the ground back (long ground contact time)
- Leaves the ground with the foot as far behind the body as possible as the primary means of acquiring stride length
In the second case, the runner:
- Strikes the ground under or marginally behind the center of mass
- Loads the ankle joint by striking down into the ground
- Uses the forward lean and elastic recoil of the tendons to acquire stride length by increasing float time.
In order to use the elastic energy of the stride, the body must be in a position that allows it to load the tendons. This is a critical point and it has direct implications on running “consciously” and having the core strength and endurance to hold this position over a long race.
Specifically, the body should:
- Be leaning slightly forward (from the ankles, not the hips)
- Be set to have the center of mass high and forward, i.e. in front of the feet (arms back/hands on the midline and body position straight and tall)
In other words, make sure your pogo stick is strong and straight and has a spring in it (i.e. your body is in a position that allows you to make use of the elastic properties of your tendons), lean slightly forward, so your energy is directed forward more than up, and jump down on that pogo stick hard and fast (Bruce Lee Style)! Then, there is nothing else to do but enjoy the ride.
Alan Couzens, MS (Sports Science), CSCS, PES, is an exercise physiologist and coach who helps athletes at www.EnduranceCorner.com. He has a passion for performance and has been coaching endurance athletes since 1993.