In the last years, multiple gait studies have appeared where it seems that mid foot/forefoot strike reduces the initial impact against the ground when running. Accordinh to this, if you land on your midfoot or forefoot, even barefooted, you will reduce therefore the forces that come to your muscles and knees during the training in comparison with a runner who lands on his or her heel
My doubts are the following ones: does not the midsole of the slipper reduce the quantity of energy that rises up to muscles and knees? Where do they measure up these forces about which we have spoken: in the treadmile or in the legs of the athlete?
It seems logical to me that a piece of rubber will absorb part of the energy created in the initial contact; that is probably the reason why we tend to be careless of our stride when running shod, as we trust the shoes will make the work for us. C. McDougall wrotte about it in his famous book,
My take is that we are careless because shoes absorb some impact...and we assume less force should be coming up to our lower legs. Unfortunatelly, this will probably encourage you to land on a unnatural way and heel strike.
Nevertheleess, if you use a rubber midsole in zero drop (or less han 4mm) shoe, you will reduce the impact on your knees because you will still land midfoot or forefoot, at least if you manage to increase your gait up to 180 steps and are able to land smoothly.
In other words: if you use a zero drop senaker with some rubber midsole, you wil loose feedback of the terrain and your nerves on the feet will have less info...but forces coming up to your lower legs will decrease.
...or maybe I am missing somethig here :D