Sunday, April 27, 2014

Quick Running Tip: Better Acceleration

I have a confession: I hate running. I really do. Although I've always been a decent sprinter, anything beyond 400-meters was just exhausting. And when I was done with my 1.5-mile runs, my legs were usually shot.

After a couple of years of enjoying spaghetti legs immediately following squadron PT, I decided to look into different ways to move forward more efficiently. As far as acceleration was concerned, I discovered that there are basically two ways to propel yourself forward when running: Active and passive.

Now I was presented with a dilemma: I wanted to give my poor legs a break, but which do I use? Both have their advantages and disadvantages, so I had to do a little more research to find my answer.

Active Acceleration
Of the two ways to move forward, active acceleration is probably the most straight forward. Essentially, you link your hips, butt, and hamstrings together to act as a single muscle. This large muscle group can then provide acceleration for a while before it fatigues. If you instead rely on smaller muscles, like the calves and the hamstrings, you can become fatigued too quickly (this was my problem).

But to use active acceleration effectively, you have to use forefoot striking (where you land on the front part of your foot). Landing this way enables you to take advantage of elastic recoil, which allows you to reuse up to 50% of your running energy. Forefoot striking also limits the amount of energy your legs have to expend to support your weight.

Finally, there were a few other changes that you have to make to your running form to feel the full benefit of active acceleration:
  • Stand straight up while running, don't slouch. Your head, spine, hips, and feet should all line up each time you make contact with the ground. 
  • Make sure to extend your hips with each stride so that you "kick" backwards slightly. You can generate more power with your hips than your legs.
  • Your feet should start accelerating backwards just before they make contact with the ground. This eliminates braking.
  • Don't push-off until your foot is behind your center of gravity. This allows you to use more elastic recoil for acceleration.

The video below demonstrates active acceleration:

Passive Acceleration
Next up is passive acceleration, which only uses the legs for support, letting gravity pull you forward with each step. As of today, there are two popular passive running methods that you can use: ChiRunning and Pose.

The ChiRunning method has you imagine you have four gears of acceleration, with each gear correlating to about an inch of forward lean. With each stride, your heels will move in a circle, much like it would if you were pedaling a bicycle. The ultimate goal of the ChiRunning method is to move forward as efficiently as possible.

Below is an example of ChiRunning's method of passive acceleration:

The other approach, championed by the Pose Running Method, describes its version of passive acceleration a bit differently than ChiRunning. Unlike ChiRunning, you won't be moving your heels in a circular motion. Instead, you have three positions to each stride: Pose, fall, and pull.

The pose position describes the point where your foot makes contact with the ground and your foot, hips, shoulders, and head are lined up. The fall position describes the forward lean (which is where you get your passive acceleration). And the pull position describes you pulling your feet up off the ground between each stride. Essentially, you run in place while leaning forward.

I'm sure that didn't make much sense. The video below does a better job of showing you what pose, fall, and pull are describing.

On a final note, if you look closely to both methods of passive acceleration, you'll find that ChiRunning and the Pose Method are pretty similar, differing primarily on where the foot strikes the ground. ChiRunning wants you to midfoot strike, while the Pose Method wants you to forefoot strike.

Which to Choose?
Active acceleration is probably the easiest to master and will quickly improve your running efficiency if your form isn't so good. However, using active acceleration still involves your muscles, so it isn't the most efficient acceleration option.

On the other hand, passive acceleration is more efficient because it uses gravity (or controlled falling) to generate forward motion, but it requires you to master forward lean, which takes some getting used to.

So, in my opinion, if you have to improve your run times in a hurry, I would focus on mastering active acceleration first. When you have some more time, I would then move on to mastering passive acceleration, picking either ChiRunning or Pose Method.

Have some feedback? I'd like to know what your experiences were with either passive or active acceleration.

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