I understand the fact that you want to train with different shoes (in terms of drop etc.) in order to modify the supports according to the stride, therefore not always soliciting the same muscles in order to avoid injuries. But how does running in ultra-maximalist shoes like the adidas prime X running shoes, with 50mm soles, really help? These shoes spare the muscles so much that they are not used and therefore do not progress, so what is the point of training if it does not generate muscular adaptation? There are always cardio-respiratory adaptations, but at that point you might as well be cycling, right?