Many people complain to me about the outside of their shoe being worn excessively. They say they aren’t experiencing any exceptional amounts of foot pain, but they are concerned that something is wrong. They often report that it doesn’t wear unevenly anywhere else on the shoe. The truth is, the outside of everyone’s shoe wears faster and if they pay closer attention it probably is worn out differently on different parts of the shoe. That is 100% normal. This will explain, for both walking and running, why the outside of the shoe wears faster.
Gait (a fancy word for walking) is divided into two major phases with sub-phases. The gait cycle refers to one side of the body’s rotation from the time the heel hits the ground, rolls forward comes of the ground and then hits again. This is referred to as one gait cycle. The main difference between walking and running gait cycles is the addition of the “float” phase in running. This is when neither right nor left foot are in contact with the ground.
Stance phase (60% of cycle)-This is any time one foot is in contact with the ground. Remember that gait cycle only refers to one limb. While one limb is in one part of the gait cycle, the other limb is in the exact opposite part. When the right foot is in the middle of stance phase, the left foot should roughly be in the middle of swing phase.
Stance phase sub-categories:
- heel strike-this is when one heel (right or left) first contacts the ground. When the heel strikes, it is slightly inverted (turned towards the midline of the body) resulting in more wear on the outside of the heel of the shoe.
- midstance-during midstance the foot continues to invert (turn in) before it quickly starts to evert (turn back out). This shows uneven wear along the outside of the bottom of the show
- heel off-the heel starts to lift off of the ground in what should be a neutral position. There is no such thing as the perfect foot so perfectly neutral does not truly exist. This is where custom orthotics can become highly beneficial. Neutral is defined as being in-line with the lower leg.
- propulsion-The motion of the foot moves from the outside towards the big toe as the foot continues to evert (turn out). Weight moves across the ball of the foot from the outside in until you propulse yourself from off of your big toe. At this point the heel slightly everts from midline.
- toe off-your body weight shifts out over your foot and you enter swing phase as the toe disconnects contact from the ground.
|Foot Motion during Stance|
Swing phase (40% of cycle)-The goal of swing phase is to clear the foot and leg from the ground, swing it forward over the contralateral (other) limb and catch your momentum coming down.
- toe off- end of stance phase/begins swing phase.
- acceleration-as the other side is going through stance phase, body weight is propulsed forward carrying with it your momentum. The muscles of your hip, thigh, leg and foot are simply using momentum during this point to literally “put one foot in front of the other”. Energy is expended during swing and acceleration, but it is less than when propulsing body weight forward. The foot turns outward which shortens the limb making it easier to clear the ground.
- deceleration-to prevent momentum from making the body “getting ahead of itself”, aforementioned muscles must now slow the limb down to prepare it for heel contact. The lower leg rotates preparing the heel to again be inverted (remember-uneven wear on outside of your heel) for heel strike.
- heel strike-start of stance phase/end of swing phase. Heel is inverted.
Important foot anatomy
Here are some other points to remember about the foot. The foot is divided into a medial (inside) and lateral (outside) column. The medial column is a “flexible adaptor” with more motion and flexibility. The lateral column is a “rigid lever” which allows the aforementioned gait cycle to propulse from lateral to medial and out through the big toe.
The medial arch acts like a shock absorber, bowing and flexing when needed. When running on a sandy beach or soft grass, the position and balance receptors in your body will communicate this surface with your noggin. The foot will automatically adapt to the soft, uneven terrain and without intention you will use more of the inside of your foot. Try jogging 6 miles on a beach then see where your feet are most sore. Overpronators or flat-footed individuals naturally put more pressure on the inside of their arch leading to arch fatigue and plantar fasciitis (heel pain).
The bones of the lateral arch have significantly less motion than the medial arch. They are meant to lock and give you a solid surface from which to spring forward. Individuals with a high-arch or supinated foot type often put excessive pressure and strain on this part of their foot.
When I first studied biomechanics I paid more attention to my gait when running. I started to try and adapt; invert more at heel strike, feel the leg turn outward and propulse through my medial column. The best way to run is as natural and comfortable as possible. You can pay a running coach a lot of money to strengthen certain muscles, and use certain form but for the non-elite, amateurs and “fun-runners” out there, just be yourself when you run! You will do more damage trying to change the way that you run, than just staying loose and allowing your body to move how it is meant to.
For more questions about walking, running, foot types, foot pains and foot and ankle problems contact
Dr. Marcin N. Vaclaw
Foot and Ankle Specialists of The Woodlands
9191 Pinecroft Dr #225
The Woodlands, TX 77380