Tag Archives: pronation

A bit of running advice.

During the swing phase, lead with your knee, not with your foot. By “floating” the knee in front of you as your leg swings up, maintaining knee bend as long as possible, you will:

  1. Increase full-body forward lean.
  2. Allow a complete contraction of the extensors (gluteus maximus, hamstrings, and calf muscles).
  3. Allow a complete contraction of the flexors (Sartorius, iliopsoas, frontal calf muscles).
  4. Increase your speed by increasing thigh spread (the distance between your swing thigh and your pushoff thigh).

Galen Mo

Look at Galen Rupp and Mo Farah in the picture above: their swing thighs are in a very similar angle to the ground despite Galen being in late stance phase and Mo in early pushoff. (The main difference is the angle between their thigh and their calf, not the thigh and the ground). You can see that their swing hip is completely rolled forward, meaning that their feet (off camera) can easily manage full pronation.

Floating the knee should feel like you’re falling, similar to what you feel during a lunge, except that your foot ends up coming down under the center of gravity. You should feel your swing hip hike up and your pushoff hip press down. Master this by skipping, focusing on bringing your knees far, far in front of your body with your thighs in a straight line.

Bonus points: Look at their body geometry. At the height of the swing phase, you can draw a straight line from the top of the knee to the bottom of the elbow in both athletes, smoothly connecting thigh and forearm. Elegance always holds the key to speed.

Don’t run above your pay grade: the (not so) hidden dangers of maximalist shoes.

There is a segment of the running community that continues to insist that maximalist shoes are the way to go, and that minimalism is nothing but a “fad.” This insistence goes against every biomechanical and physical principle that I can think of. One of the ways in which maximalist shoes violate these mechanical principles is by having wide soles. This is incremental: the more maximalist, the greater the violation.

When running in maximalist shoes, the impact forces incurred during the landing phase are much greater. Take for example the following picture, which shows the back of a shod and an unshod foot. When the foot is fully pronated at the point of ground contact, the sole forms an acute angle with the ground. The vertex of the angle is the outside of the foot; the point of contact. When the runner is unshod, the sides of this angle aren’t very long. I represent this as the innermost arc (from the vertex). However, when the runner is shod, the sides of the angle are much longer; this is the outermost arc.

shoe vs. foot

Because the arc is much longer when the foot is shod, the inside of the foot will accelerate over a comparatively longer distance (the length of the bigger arc) in order to lay flat on the ground. This means that the overall forces that travel up through the foot and into the leg are that much greater when running in big-soled shoes.

There are two important points here: first, the modern running shoe was designed to artificially extend the stride. As the stride extends, the impact forces are greater and greater. This isn’t a problem when the runner’s muscles have developed to extend the stride; most likely they have also developed to absorb and dissipate those increased impact forces. But when the stride is lengthened artificially, the runner hasn’t “earned” the right to interact with those forces—and they’ll get injured.

Similarly, the shod foot in particular has no business having a wider sole. By definition, a habitually shod foot is weaker than a habitually unshod foot. And because the forces created upon landing/supination are much greater when shod than when unshod, the possibility of injury skyrockets: the weakened structure is generating with forces much greater than those which the stronger structure would ever generate.

That’s a bit of a problem.

But there is a second point to be made here: this analysis is based on simple physics and geometry. And yet, the multibillion-dollar running shoe industry pays very little heed to the physical, biological, and mechanical principles by which the body moves, and by which it grows and develops.

Out on the road, halfway into the marathon, the maximalist/minimalist debate doesn’t matter. Out there, you aren’t debating the minimalists. You’re debating physics. You’re debating biology. You’re debating geometry. If the worldview that you approach that debate with doesn’t heed the relevant laws and principles, you’re going to lose. In direct measure to how badly you lose this debate, will be the magnitude of your injuries.