Ardipithecus ramidus 4.4 Million Years Ago, the best of both worlds
The foot has a tripod design of three arches. These arches are the Medial, Lateral and Transverse arches. In addition to their primary role of storing and returning energy to the ground as a primary component of our gait (think of springs), they each provide specific functions for physical stability, neurological development and even our emotional and cognitive interactions with our environment. The foot arches probably developed from a more hand like structure able to grasp branches. We still maintain vestiges of this in our Medial Arch which runs from our heel to our big toe.
It is helpful to understand arch function from the viewpoint that the foot developed to transverse rough ground barefooted and to grip the surface as much as possible as well as add force to our gait. Wearing shoes and walking on hard, flat surfaces are not for the benefit of our feet, but to rather accommodate the parameters of our engineered environment. The consequential repetitive motion limits the development of the neuro-motor potential of the lower leg / foot system and makes it more vulnerable to injury. Issues can also manifest as knee, hip, sacroilliac joint, neck or other problems.
Interesting overview of foot mechanics research
When foot function is compromised we feel less stable and less connected to the ground. This is often experienced in feeling less safe. Our bodies respond by being more vigilant and ready to respond to danger. This means our fight and flight mechanism is hyperactive resulting in more stress, compromised immune function(1), developmental challenges(2), anxiety and a host of other challenges to living. Even wearing heels can trigger some of these effects(3).
The Medial Arch is perhaps the arch most commonly associated with foot function. This runs from the big toe and the ball of the foot on the inside to the heel. When the foot is aligned so that the big toe points straight ahead, this arch is the primary source of locomotive interaction with the ground.
The Lateral Arch is a much shallower arch alongside the outside of the foot. This arch participates in locomotion and has a primary role in turning and lateral stability, keepings us from falling sideways. It is sometimes described as functioning like the outrigger on a canoe.
The Transverse Arch runs along the ball of the foot from the big toe to little toe. This arch functions in locomotion and also helps us to grip rough surfaces. It also plays a major role in lateral stability, preventing us from falling to the sides when turning. All of the arches function like springs, storing and returning energy in our gait, however in addition to grip, this is the primary role of the transverse arch.
(1) Negative Impacts of Stress on Health
(2) Foot Loading dynamics and Reflex Integration
(3) Wearing Pumps
(4) S. Masgutova
(5) T. Meyers, Anatomy Trains
(6) Brian Esty 2011
Shoes
Shoe function can range from actively supportive to actively degrading foot function, as in high heels(1). One thing all shoes have in common is that they insulate the foot from the ground, which is of course part of why we wear them. The downside of insulating the foot is that the tactile and proprioceptive sensory systems of the feet do not have much to say. These sensory systems have a lot to do with postural and dynamic neuro-motor function, providing feedback and new information on qualities of our surroundings. Also the motor systems in the feet that adjust to variations in the ground are passive. Consequently encasing these sensory and motor systems in shoes limits their development and function.
Disconnecting from the ground can have emotional repercussions in feeling less stable and safe, disconnected and isolated. This can stimulate our fight and flight response(2). There is also evidence that electrical contact with the ground, “grounding”, has many diverse health benefits. It makes rather a lot of sense that being grounded has a regulatory effect on our electrical nervous systems.(3)
1: Wearing Pumps and Low Back Pain
3: Pilot Study on effect of electrical grounding on biological functions