What is the proper amount of cushioning for running shoes? The answer to this question is not that simple. There are several factors to consider when it comes to cushioning.
Studies on test subjects have shown that when there is less cushioning in the shoe, the body compensates by absorbing more shock with the musculature of the feet and legs. There is an argument that by minimizing the amount of cushioning provided by the shoe, the foot, and therefore the body functions more naturally when running. Keep in mind, however, that this assumes that the sole of the shoe is also not thick or stiff. The argument then follows, that by running more naturally, one would be running more efficiently, thus reducing the chance of injury. Counter-arguments to that would be that the additional energy required in muscular activity to absorb shock would offset these efficiency gains and lead to earlier fatigue. Also, is running more “naturally” on “unnaturally” hard surfaces such as asphalt or concrete in minimally cushioned shoes really better or safer? Finally, how would older, stiffer, less pliable runners, or more overly-flexible (hypermobile) runners, or runners with bony prominences under the ball of the foot respond to less cushioned shoes?
My feeling is that, because of the many factors involved, determining the proper amount of cushioning for each individual runner is….well, an individual decision. Trial and error with what feels best and allows the most comfortable running may be the only way to determine what is optimal for you. Changes in the amount of mileage/intensity performed should be made gradually, when switching to shoes with noticeably different cushioning properties. You should be on the lookout for how your body is responding to the changes. New aches and pains that are hanging on or worsening may be a sign that the change was not appropriate. Also, what works best for you at age 35 may not be the optimal choice at age 55: more cushioning may be needed as one ages. Think about the way a 5-year-old can run and bound around barefoot on hard surfaces for hours without the slightest hint of discomfort in their feet or legs. How easily can you do that now?
Finally, cushioning has to be factored in with the surfaces you are running on, as you may be better off with more cushioned shoes
on harder surfaces, such as asphalt, than softer ones, such as grass. One must also factor in other features of the shoes, including sole thickness, heel drop, shoe stability and stiffness, etc., as these properties will combine to have specific influences on the properties of the shoes and the way you function in them.