Biomechanics 101

by Super Dave, Industry Expert

What do your biomechanics have to do with better running and staying injury-free? Just about everything. And you want to ensure you have a smooth, natural gait cycle by getting shoes that match up to your biomechanics. How do you figure out which shoes go with which feet? First, you need to understand how to "read" your biomechanics - your gait cycle and type of pronation - and then let that dictate how you look for your next pair of shoes.

Gait Cyle
Pronation & Shoe Categories

Gait Cycle is the progression of the foot through each stride as the heel strikes (phase #1), rolls to midstance (phase #2), then to toe-off (phase #3).

3 Phases of the Gait Cycle:
1. Heel Strike
Running is a "High Impact" activity. How much impact? Wanna guess? Since at some point both feet are off the ground, a runner lands on their heel with 3.5 times his/her body weight! What does our body need to do with all that shock? Absorb it! Cushion it! Dissipate it! Disperse it! If we don't, it travels back up the legs, causing injury.

2. Midstance Phase
From the heel strike, your foot rolls on to the midstance. As the name suggests, this is when you're standing over your midfoot. What do we have in the midfoot? The arch! As you can imagine, placing your entire body weight over your arch causes it to flatten somewhat. How much depends on what kind of arch you have (low, average or high). More on this later.

3. Toe-Off
The toe-off propels your foot into the next stride where the gait cycle starts all over again. But how you propel yourself at toe-off (as told by the wear pattern on your shoes) gives the most important clue to what kind of shoe you need.

When your running shoes are well matched to your feet, the gait cycle happens smoothly and naturally. Result: one happy, healthy runner that doesn't notice his/her shoes during the run!

What your old running shoes can tell you about your new running shoes
Remember we mentioned looking at the wear pattern on your shoes? Most runners look at the bottom of their running shoes and conclude that they wear out the outside of their shoe because the outside heel is worn. From this, they may conclude that they need a Neutral shoe. Most are wrong! Everybody wears out the outside heel. It's the wear pattern at "toe off" that will determine your rate of pronation, and therefore the type of shoe you should be running in.

Here is the secret: the more your wear pattern is concentrated towards the ball of your foot, the more you are pronating. A centered wear pattern is best. Wear mainly at the ball of your foot means a lot of pronation, so your new shoes should be from a more stable category (Stability or Motion Control) than your old ones. On the other hand, wear at the little toe (outside) of your shoes means too little pronation, so your new shoes should be more neutral (Stability or Neutral) than your old ones.

Are your old shoes worn evenly across the toe area? Congratulations: you're in the right shoe category...stick with it!
back to top

What is Pronation?
Pronation is the natural, inward roll of the foot. Pronation begins when the heel contacts the ground, the foot then rolls inward to absorb shock and finally transfers weight to the ball of the foot as it prepares to push off. It is a natural and necessary motion for running and walking.

There are three types of pronators and shoe categories that work best for them:

1. Overpronator (Low/Flat Arch): Your feet are very flexible which means a flat arch absorbs very little shock. That shock and the excessive inward roll are transferred through the leg. Too much of that and the leg gives out in the form on an injury. Your shoes need to supply a lot of the support that a flexible foot lacks. To ward off injury and put the foot in the proper track, start your search with Motion Control shoes.

2. Natural Pronator (Medium Arch): Your foot has enough structure to avoid totally flattening out during the gait cycle, so you pronate naturally. Natural pronators disperse shock effectively. Look for Stability shoes to provide the moderate support that maintains this natural-pronation and protects against over-pronation.

3. Underpronator/Supinator (High Arch): Your foot is rigid which limits sufficient inward motion (pronation) of the foot. So, a high arch absorbs less shock. A flexible shoe helps maximize your natural pronation and provide more of the shock absorption you need. Well cushioned, highly flexible Neutral shoes are best for the underpronator.

Bottom line: pronation (like ice cream and a lot of other things in life) is good in moderation.
back to top

Okay, I found my shoe category. What's next?
Shoes for bigger runners: Do your shoes seem to wear out too quickly? Do your heels really slap the ground when you run? You probably need "more shoe". Men over 180 pounds and women over 160 need shoes with more shock absorption built in. Look for shoes from your category that include the word "Plus".

Shoes for fast running: When running at a faster than average pace, your feet spend less time on the ground and your heel strike impact is somewhat less than the usual 3.5 times your body weight. Therefore you need less shoe on your foot. Look for shoes from your category that include the word "Performance".

If neither of these applies to you, just stick with your standard shoe category.