The type of running shoe is a key decision that any runner needs to make. The good (or bad) news is that runners should have at least two pairs of running shoes and rotate them on different days. This study shows that runners who use more than one pair of running shoes are less likely to get an overuse injury.
Probably the most likely reason for this is that different running shoes will stress a different set of tissues differently. For example, running shoes can come with different ‘drops’. This is the height difference of the midsole between the heel and forefoot. Some running shoes are 10-12mm, some are 8mm and a few are down to zero. It is not hard to see that running in a 10mm drop running shoe one day and a 0mm drop running shoe the next day how the load or forces on the calf muscle are going to be different.
Moving the loads around like this can be important in preventing injuries by stressing tissues differently from day to day. The best way to do this with running shoes would be to make sure that the design features in the 2 or 3 or more shoes that you run in a very different from each other. Also, it is important that you spend time to adapt to any new running shoe so the body gets used to them, especially if they have design features that you are not used to running in.