“The human foot is a masterpiece of engineering and a work of art.” – Leonardo DaVinci
As is evident from his sketches of vitruvian man, Leonardo DaVinci had a strong affinity for the measurements and function of the human body. He was also a very accomplished mechanical engineer and architect, among other things. Given his genius and his legacy of great works, his quotation about the human foot should be taken into deep consideration.
The Power of the Arch
The key to quality architecture and engineering is a design that will bear load and distribute force in the best way possible. One of the simplest and widely used structures is the arch. The arch, notably used in bridge design, is able to reduce shear, tension, and torsional stress by taking advantage of the compressive force on the arch and making the whole structure more stable horizontally. Though the first arch bridge dates back to 1300 B.C., they weren’t used extensively until the Romans utilized them in structures such as the Segovia Aqueduct (A.D. 100). Below is a basic illustration of an arch bridge:
In an arch bridge, the keystone bears the brunt of the force from the mass above it. Force is transferred horizontally along the components of the arch all the way to the supporting abutments, which are positioned securely on the ground. As long as the abutments are securely positioned, the whole structure will be rock solid. The more compressive force that’s placed on the keystone, the stronger the arch becomes. Many arch bridges are constructed using a heavy fill material to increase the weight on top of the keystone in order to make the arch more stable and resistant to shear and torsion.
The Rainbow Bridge near Niagara Falls is a more modern steel version of the arch bridges originally popularized by the Romans. Unlike Roman concrete architecture that utilized many rows and sometimes multiple columns of arches for a single bridge, steel architecture allows for a long single span to be covered with one arch.
Arches of the Foot
By now, almost everyone has heard about arches in relation to the foot. Whether you’re talking about arch support or flat feet, the concept of the arch is widely known. What you may not know is that the foot has three distinct arches, which are shown below.
One of the reasons Da Vinci was so mesmerized by the human foot is because our foot arches work much the same magic as arches do in bridge construction. While it’s phenomenal that we can exert hundreds (or even thousands) of pounds of compressive force on a foot that has a relatively small surface area, it becomes more understandable after learning about arches. Similar to a Roman concrete bridge, our arches also have keystones, only instead they are made up of bone.
Refer to the picture above to locate the keystones for each arch. In the anterior transverse arch, the keystone is the intermediate cuneiform. In the lateral longitudinal and medial longitudinal arches, the keystones are the cuboid and talus, respectively. As these keystone bones are compressed during everyday activity and exercise, the vertical compressive force is transferred horizontally along the arches and is distributed to the ground. Just like a bridge arch, compressive force on the keystone bones will help to reduce shear and torsion forces on the whole structure (the foot and ankle).
Knowing what you now know about arches, go back up to the diagram of the arch at the top of the post and imagine each abutment is resting on top of a Godzilla sized air mattress. That is a surefire way to take an ingeniously designed support structure and render it immediately unstable. The second you place an arch on a giant marshmallow (running shoes), the stability and strength is severely compromised.
Your response might be that cushioned heels allow us to run on pavement without as much jarring force as we would experience barefoot or in flats. Actually, the opposite is true. When you run in cushioned running shoes, heel striking becomes the norm since there is no pain associated with it due to the shoes. However, this is not the natural way we were designed to run and use our foot arches. The results of this Harvard study show a significantly steeper acceleration of impact force from heel striking than from striking with the mid or forefoot. There’s no question that heel striking is the wrong way to run and puts a great deal of stress on ankles, shins, and knees. If you have any doubts, do a little experiment. Take your shoes off and gently run in place on a hardwood floor. Without thinking, you’ll immediately start landing softly on the mid and forefoot, taking advantage of your arches. You’ll have to force yourself to land on your heels, which will be a much more uncomfortable experience.
Now let’s consider arch supports. First off, realize that there isn’t a single arch structure in the world that requires support. The arch derives its strength from the fact that it is unsupported by scaffolding and can compress and become more stable. Now also consider that we are not made of lifeless stone, but of living tissue that must grow and be used constantly in order to remain strong. If you or anyone you know has ever broken a bone, you probably have some experience with joint or limb support, also known as a cast or a brace. What happens after wearing one of these for a while? Muscle, soft tissue, and bone atrophies to the point that it is noticeably weaker and smaller than the unbraced limb. If you have fancy shoes with arch support or custom orthotics, you’re effectively casting your feet every single day. It’s no surprise that there is such an abundance of foot problems in our society today. Our species has thrived for millions of years without the need for constant artificial support in any part of our body.
Performance and Health = Uninhibited Ground Contact
You might be wearing cushioned shoes because ‘that’s what everyone does’ and ‘you’ve done it forever’. You may also think (thanks in no small part to the brilliance of marketing) that all of the professional and elite runners wear cushioned shoes. Would it surprise to you to find out that hardly a single thing has changed in performance shoe design over the past 75 years? Below is the Adidas shoe that Emil Zatopek used to win the 5,000 and 10,000 meter races in the 1952 Olympics. The second picture is the most recent performance track flat designed by Nike for professional track athletes.
Other than the price, the marketing, and the color scheme, nothing has changed. The reason for this is the simple fact that effective and high performance running is done best when there is as little material between foot and ground as possible. Going back to the arch, this makes complete sense. If you consider that the bones and muscle fascia at the ends of the foot act similar to abutments in an arch, the most strength, power, and stability will be derived from having those abutments connected to the ground with as little interference as possible. This is why powerlifters typically deadlift in ballet slippers and gymnasts perform barefoot.
While cushioned shoes will certainly inhibit running performance and expression of strength in the gym, the main problems with them is that they promote poor running mechanics and don’t allow the feet to strengthen in a natural way. First off, the vast majority of people run incorrectly already due to these shoes. And even for those that do run with a correct midfoot strike, it’s very easy to get lazy with cushioned soles and fall into heel striking. It’s like using the bumper lanes at the bowling alley. You may be knocking pins down and having fun, but you’re still doing things the wrong way and using an artificial crutch.
Transitioning to Minimalist Shoes
In order to learn how to run correctly and get the most out of lifting in the gym, you’ll be best served by finding a pair of minimalist shoes and getting used to them. While Vibram Five Fingers are all the rage right now, I found them difficult to get in and out of as well as impractical and smelly since you can’t wear regular socks with them. My number 1 recommendation would be the New Balance Minimus trail shoe. They have a nice wide forefoot to allow you to spread the toes, can be worn with our without socks, are incredibly sturdy, and have just enough cushion in the small heel nubs to make the transition from cushioned shoes fairly painless. I’m going to do a full review of them soon on the blog.
Beyond the Minimus, the Merrell Trail Glove, Vivobarefoot Evo, and Innov8 Bare-XF are really good options. When switching, take it slow and let your ankles, feet, and Achilles and other soft tissue adapt. Try running on grass or a track for a while and really be conscious of midfoot striking. You’ll probably notice that your strides will get shorter and you’ll feel like you’re gliding in a straight line like on a conveyor belt rather than in a jerky up and down sort of way. Eventually, it’s even fun to experiment running on grass barefoot. Not only will this improve your stride, but tactile contact between your feet and the ground will enhance your stability and coordination.