Impact

Our weight-bearing contact with the ground is intimately connected to foot-sense. For many years, sport-shoe manufacturers focused on impact, promoting shoes with shock-absorbing materials to protect us from the impact forces that supposedly caused injury. But after decades of scientific research, experts are unable to demonstrate that our feet are vulnerable to injury from the result of impact, whether from standing, walking, running, or jumping. In fact, what the studies show is that there’s no difference in injury rates between running on hard surfaces and soft surfaces, or between runners who have heavy or light impact on the ground.

Certainly, excessive impact can injure our feet. And any impact can cause injury when muscle imbalance is present. However, the action of standing, walking, running, and performing other common types of physical activity is quite natural—our feet are made for these activities and the normal impact associated with it. The forces of impact are a natural phenomenon our feet are made to deal with. Actually, our feet use the impact on the ground to decide how much muscle work is needed to run most efficiently. This action is mediated through the nerves and muscles in the feet.

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The muscle response to impact also affects comfort. For this reason, all shoes, from the moment you put on a new pair to those that appear too old and worn out, should be completely comfortable. Otherwise, the shoe should not be worn because of the risk of foot damage. Shoe companies may claim that running shoes should be changed every several hundred miles, but comfort is your best guide. So-called worn-out shoes may be just fine as long as they are comfortable and not falling apart.

Still other benefits are obtained from our constant impact on the ground. Bone strength can be improved in those who perform activities that result in harder impact, such as running, especially when compared to activities that have low or almost no impact such as swimming.