In the world of running shoes there are two types of shoes. There is the traditional shoe and the minimal shoe. Each one of these shoes affects the user in several ways. The shoe affects the muscles in the legs and feet, the biomechanics, the amount of neural stimulation, and the physiology of the runner.
The traditional style shoes cause most runners to change their biomechanics to a less than natural stride. These shoes cause a runner to heel strike, which is landing on the heel when running. The foot lands on the heel and then rolls toward the toe.
Once the weight is rolled onto the toes, the runner pushes off to take the next stride. This takes away the use of the eccentric movement of the soleus and gastrocnemius muscles and causes them to work concentrically. Additionally, the quads are use to extend the knee and push off. The planter flexion action and knee extension cause a vertical movement when running. This is extra energy used that is not nessecary.
When were wear proper or minimal footware (shoes that don’t have arch support and have a flat sole) we learn to run the way our bodies were made. This allows us to use the eccentric abilities of our quads, lower leg muscles, and tendons. We can save tons of energy by turning running into a plyometric exercise that takes advantage of the elastic properties and stretch reflexes of our legs. We are then able to use the powerful and efficient hamstrings to run.