April 28, 2010 (Boulder, CO) – One of the prime aspects of running I enjoy most is its simplicity.  In the equipment intensive sport that can be triathlon, the most technical equipment needed for running is a good pair of running shoes.  Although wading through the terminology and range of products can be daunting for those new to the sport, choosing the right shoes for your individual biomechanics need not be difficult.  This article provides an overview of some basic terminology, and shows you how to analyze your foot biomechanics so you'll have a better idea of what to look for when you choose your running shoes.

First, some terminology:

• Pronation refers to the movement inward of your sub-talar joint upon landing. Pronation is what allows your body to absorb the shock of your footfall. Four to six degrees of pronation is common and necessary for shock absorption.

• Overpronation refers to the act of pronating, or moving inward too much—namely, more than six degrees—after footfall. Just under half the population tends to overpronate. Overpronation can cause some problems if not corrected. During a run, your feet play an important role in the repetitive task of shock absorption. Overpronation leads to excess torque on the medial, or inner part of the leg. Medial shin splints and medial knee pain are common injuries associated with overpronation.

• Underpronation occurs when a foot strike results in less than four degrees of pronation, which can lead to inadequate shock absorption.

• Supination is the outward movement of the foot after striking. Supination is very rare—only two to three percent of the population actually supinates upon footstrike. Supination is sometimes confused with underpronation.

• Neutral runners are the lucky ones. They pronate just enough to absorb the shock, and not too much to cause excessive strain on the lower legs and knees.

So, given these terms, how do you know which one best characterizes your own biomechanics? 

Let's start with the general rule of thumb based on arch height.  Generally, individuals with a high arch tend to have a rigid foot structure that doesn't give much, i.e. doesn't pronate.  Those with high arches are therefore usually neutral runners or underpronators.  Conversely, most individuals with flat arches tend to overpronate. 

However, like any rule of thumb, exceptions exist.  The best way to determine your individual foot biomechanics is to undergo a more thorough test that involves examining your foot structure as you stand, walk and finally run.  This will require another pair of eyes; and most specialty running stores can provide this type of examination when you go in to purchase a pair of shoes.

The first step is to look at your foot structure while standing naturally, looking straight ahead, with shoes off and pant cuffs rolled above the ankles.  Notice what the arch looks like.  Is it high?  Flat?  Next, look at the pointy ankle bone on the inside of your leg.  Is it in a neutral position?  Or does it collapse inward a bit while standing?  Here's where an experienced pair of eyes (e.g. a coach or running store specialist) can help with the analysis.

A high arch with a neutral sub-talar joint tends toward a neutral to underpronating gait.  A sub-talar joint that is less than neutral, which is often accompanied by flatter arches, is typically the sign of an overpronator.

The next step is the walking test.  Walk normally for about ten meters and then back.  Your analyzer should focus on what the sub-talar joint does after foot strike.  Remember, four to six degrees of pronation is normal and necessary for shock absorption; but much more than that becomes overpronation. 

>>>

The Colorado Triathlete
© CO TRI, LLC - All Rights Reserved