Barefoot running or “natural running” is growing in popularity in the modern world. However, it is the way we all ran until the Romans starting building roads and it is still the way many people run in third world countries.
When you run wearing a modern shoe, the heel tends to strike the ground first. Although this is thought to be a more efficient way to run, it transmits tremendous shock to the body. Therefore, modern running shoes have cushions soles that are thickened in heel to absorb this shock. The soles are also quite stiff, resisting movement.
When you run barefoot the natural tendency is to land on your mid-foot or even on the outside of the mid-foot. This minimizes the forces transmitted to the body. People that run in this fashion can adapt to even hard surfaces like roads and sidewalks and are able to run without discomfort.
As I have aged, I have gradually shifted my running from the road to grassy fields and the beach. It helps that I live about a half a mile due west of the Atlantic Ocean. I have not, nor do I intend to learn to run barefoot on the pavement, but I really prefer to run barefoot on the beach.
I schedule my beach runs to coincide with low tide. The beach is much closer to level and more hard packed along the water’s edge at low tide. When I was training for my one and only marathon, I found that the angle of the beach inflamed by ITB (iliotibial band) if I exceeded 5 miles. The angle at high tide will stress the ITB in just a couple of miles.
