What’s in a Shoe? Stability.

Everyone’s Feet pronate. Pronation is when your foot rolls inward to distribute the forces of impact as your foot makes contact with the ground. Normally, this is about 15%. The arch of your foot is the biggest factor in your pronation.

There are three basic types of shoes as far as stability goes. A neutral shoe, which allows your foot to move in its natural way; a stability shoe, which gives your foot some assistance to not over pronate; and a motion control shoe, which gives your foot maximal support to not over pronate.

If you go into a running store to purchase your shoes, they are likely to watch you run and walk in bare feet and then with various shoes on. They are trying to determine if you pronate, supinate beyond what’s normal. Their recommendations for shoes typically follow this pattern:

People with normal arches will typically run in either a neutral or stability shoe.

Those with low arches or flat feet typically use a stability or motion control shoe. Flat footed runners typically overpronate meaning their foot rolls in farther than it should toward the big toe. Because of this, a stability shoe is usually a good option. However, if you see that the outside of your shoe’s sole is being worn faster than the rest, you’ve got too much control going on in the shoe and need to switch to something neutral.

Heavier runners (men between 160-180 and women 140-160) who over pronate will likely need more than just the average stability shoe. Look into the motion control shoes to help with the overpronation.

Those with high arches under-pronate (supinate) and so typically do best in a neutral shoe. A little note here: Women have a greater quadricep angle and wear down the outside of their shoes more quickly than men, but it doesn’t mean you supinate.

Over or under pronation can place you at high risk for particular types of injuries. Overpronation causes extra stress and tightness in the muscles. Too much motion in your foot can cause calluses, bunions, runner’s knee, plantar fasciitis, and Achilles tendinitis.

Under pronation (supination) places extra stress on the foot, which could lead to you developing ITband syndrome, Achilles tendinitis, and plantar faciitis.

The problem with all of this information is the research doesn’t really support it. It’s all theory. Now, I’m not saying you should throw out your tried and true running shoes and go with something different as far as stability. What the research supports is choosing the amount of stability that you are most comfortable in. This may take some trial and error. You can pull on a pair of shoes and they feel great in the store, but when you take them for a run, they just don’t work. This is why you should always check the return policy of a store before you buy the shoes.

Pronation can change as you become a more experienced runner because the muscles and tendons of your feet and ankles become stronger. When I first began running, I overpronated, then I supinated for a while. When you go to get new shoes, try some different things on. You may find your feet have changed and you’re more comfortable in a different shoe.

The stability of a shoe won’t necessarily impact your ability to run faster either. The issue will be the weight of the shoe. Heavier shoes are going to slow you down. For every 100 g  of shoe weight you can anticipate a 0.8% decrease in speed. The more stability you have in a shoe, the heavier it’s going to be.

The big take away from all this is, the stability of a shoe isn’t going to reduce your injury risk. Go with what is comfortable, but check in every once in a while to make sure your favorite shoe, is still your favorite.

Happy running. Next up is heel to toe drop.

The perfect shoe?

brooks pure

Flat feet, high arches, over pronation, supination, and heel striking, as runners we hear many recommendations on what type of shoe we need based upon our foot type, but what does the research say?

Thirty-five to fifty-six percent of runners are injured each year. The type of shoe you run in, has little impact on the frequency of injuries. That’s right my fellow runners, how often you are injured doesn’t have much if anything to do with the type of shoes you run in.

A research study done in North Carolina with 700 runners, all of which had been running for more than ten years, and who ran approximately 20 miles a week showed no difference in injury rate regardless of wearing stability shoes, motion control shoes, or cushion shoes, Gross (2011). There was also no difference in injury rate based upon heel, mid-foot, and forefoot strikers.

Everyone thinks that running injuries are caused by impact forces and pronation issues.  Pronation is looked at as being a problem because the extra rotation of the foot causes more rotation in the ankle, muscles and tendons. There have been a few studies, which show that there is no difference in injury rate for marathon runners who over pronate Wen et al. (1997), Wen et al. (1998), and Nigg et al. (2000).

There have been studies on whether or not motion control shoes actually stop pronation as well. The resounding answer is No they do not change the way the foot and lower leg muscles and tendons move Stacoff (2001), Bulter (2007), and Dixon (2007).

All right so pronation isn’t the culprit we thought it was, what about impact forces? The running community has long believed that the greater the force when you hit the ground the more likely you are to suffer from injuries because of the increased stress to the foot and leg.

Studies on whether or not cushioned shoes actually reduce internal and external impact forces show that there is little to no reduction in the forces, Nigg (2000).

Another study, Nigg (1997), showed that there is not a difference in chronic injuries rate between high impact runners and low impact runners. Nor does the type of surface you run on make a difference in injury rate. To make this even more confounding, impact forces increase bone density!

Why doesn’t  impact forces have an impact on frequency of injury? Because your body adapts to the surface it is coming into contact with Nigg (2000) and O’Flynn (1996). The idea is that when you impact the ground, your foot sends a signal to your brain saying how hard the surface is and your body adjusts using your leg joints (which act like a spring: hip, knee, and ankle).  There is also research showing that choosing your shoes based upon your arch height does not reduce injuries either Knapik (2009)

When  you have a cushioned shoe, your body just takes the extra cushion into account and remains more stiff through your leg. Regardless of the amount of cushion under your foot, you impact the ground with the same force because of the sensory feedback from foot to brain.

IF shoes don’t help prevent injuries, what does? Training properly by increasing miles slowly, no more than 10% a week. Misalignment of joints, think about seeing a chiropractor. Tight soft tissues, use your foam roller.

Okay, so which shoes should I buy? The ones that feel the most comfortable. Try on different types of shoes and go for a run around the block or on the treadmill for a quarter mile. If they feel good, buy them.