Discussions about gym gear usually strike me as little more than majoring in the minors. Performance benefits are often negligible, and therefore barely worth the attention. However, when considering footwear, we all need to purchase shoes at some point - so we might as well make sure that we get the right ones. Especially because our choice of footwear in the gym may interfere with performance and increase risk of injury. In today's article I will explain why this is so, and provide you with a checklist for making sure that you are training in the right pair of shoes.

Before talking shoes, it's important to realize two things:

1) The structure of the foot, ankle, lower leg and all its bones, tendons and muscles are an impressive feat of natural engineering which is easily able to absorb and stabilize forces up to many times our own body weights. It has evolved over hundreds of thousands of years to be able to do so.

2) We use tactile feedback from the soles of our toes and feet in order to relay positional information to the brain - also called proprioception - which is then used to correct or reinforce positioning and movement.

So, if the lower leg structures are easily able to handle gigantic amounts of force, and we use tactile information from the soles of our feet to help control our joints while squatting, lunging and snatching - shouldn’t we best train shoeless?

I think so. But unfortunately we have to think in matters of protection, hygiene, and gym etiquette. So let’s make do with what we have, and consider what type of footwear is least likely to interfere with stability and sensory feedback. For this, a shoe needs three things:

1) A sufficiently wide toe box

When loading the foot, it naturally splays as a means of passive shock absorption and weight distribution. Allowing the big toe to splay also recruits the abductor hallucis muscle, which activates your arches. A narrow shoe (or tight laces!) will suppress this ability and reduce the foot’s ability to stabilize and absorb force.  

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2) Thin, flexible soles which do not deform under pressure

Thick soles both cripple the sensory feedback system in your feet and unnecessarily heighten your center of mass - which increases stability demands. The often present shock absorption units further destabilize the body, which again adds to the overall higher increase of injury and poor motor control. So you are kindly requested to leave your Air Max and running shoes at the door.

3) No heel drop (elevated heel)

An elevated heel shifts the center of mass forwards, which increases stress on the knee and may interfere with proper loading patterns of the ankle, knee, hip and back. Of course there are exceptions in cases of poor ankle mobility, or when dealing with olympic weight lifters who need an elevated heel in order to be able to maintain proper alignment, but I would advise against it otherwise.

Conclusion

In the gym we want flat shoes that are flat, flexible, have no heel drop, and provide plenty of room for the toes to splay. This means that pretty much all running/fitness shoes and urban sneakers can be discarded right away. Not to rain on the big brands' parade, though, because most of them are actually sporting a Crossfit line that adheres to our three criteria pretty nicely. I myself usually opt for a pair of worn-down All Stars. They are barely more than flat soles attached to the feet with a piece of cloth, and that is just perfect. The engineering is in the feet, anyway.