The natural motion of your foot while running is called the Gait Cycle. The Gait Cycle is broken down in to phases: heel strikes (phase #1), rolls to midfoot (phase #2), then to toe-off (phase #3).
Phase 1 - Heel Strike
Running is a ‘High Impact' activity. Every time you hit the ground, you land with an impact equivalent to 3.5 times your body weight. Think about that! So, your shoes need to Absorb, Cushion, Dissipate and Disperse the impact. If they don't, it travels back up our legs, causing injury.
Phase 2 - Midfoot phase
Question - What do we have in the midfoot? Answer - The arch!
3 Types of Arches:
||Flat - flat arches are extremely flexible and require a great deal of control
||Medium - neutral arch is ideal but could still require a degree of stability
||High - high arches are extremely rigid and inflexible and require little if any control
Phase 3 - Toe-off
The toe-off tells us what type of pronator a runner is. Look at the bottom of your running shoes and we bet you've worn the outside of your heels. From this, you may conclude that you need a cushioning shoe. You'd be 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.
What is pronation?
Pronation is the natural, inward rolling motion of the foot. Pronation begins when the heel lands on the ground, the foot then rolls inward to absorb shock and transfer weight to the ball of the foot as it prepares to push off. This is a natural and necessary motion for running and walking.
There are three types of pronators:
||Overpronator - The excessive inward roll of the foot. A flat foot absorbs a lot of shock. It is very flexible and needs support. Motion control shoes work best for overpronators.
||Neutral pronator - The foot pronates naturally. Mild pronators disperse shock effectively. A medium arch absorbs shock moderately. Cushioned shoes or Stability shoes work best for the neutral pronator.
||Underpronator (Supinator) - the lack of sufficient inward motion of the foot. A high arch absorbs less shock. Cushioning shoes are the only shoes recommended to the underpronator. Only a small number of runners would truly be underpronators.
For the three types of runners, there are three types of shoes:
- Motion Control – the right choice for the overpronator
- Stability – a lot of runners slightly over-pronate. Pick a Stability shoe. If your foot is truly neutral, a Cushioned shoe will be fine.
- Cushion – the shoe for the neural foot or under-pronator (supinator)
Shoes are also shaped differently to help ‘steer' your foot in the right direction.
Three types of shoe shapes:
- Straight - shape found in motion control shoes built for overpronators
- Semi-curved - shape found in stability shoes built for mild pronators
- Curved - shape found in cushioned shoes built for underpronators
There are shoes designed for heavier weight runners and shoes designed for lighter weight runners.
- The average male weighs 75 - 82 kilograms (11st 8lbs – 12st 9lbs). Anything below range is considered a lightweight runner and anything above is considered a heavy weight runner.
- The average women's weighs 56 - 68 kilograms (8st 8lbs – 10st 7lbs). Anything below range is considered a lightweight runner and anything above is a heavy weight runner.
A shoe is made up of three parts: Upper, Midsole & Outsole
Upper - Holds the foot in place will almost certainly be made of a nylon mesh for breathability and will have synthetic leather overlays for durability. Reflective materials for safety at night.
Midsole - Most important part of shoe. There are three materials that make up the midsole:
- EVA – a lightweight, foam-based cushioning material
- Dual-density EVA: In many shoes you'll find what's known as a ‘medial post' (medial because it's on the inside of the shoe). A medial post is a firmer, denser, stronger piece of EVA placed in the shoe to reduce the amount of pronation.
The length of the post determines the amount of control.
Very durable cushioning
It is more durable & stable than EVA, but it weights more and is firmer. Often found in Motion Control shoes.
Outsole - Has tread for traction, flex grooves for flexibility & protects from road / stones. Often made of one or a combination of:
- Carbon rubber is very durable - same material as tires.
- Blown rubber – a rubber with air injected in to it. It's lighter, more flexible, provides a smoother ride (more cushioned) but not as durable).