There are literally hundreds of different running shoe brands and models, and they're all probably created to meet the requirements of each and every distinct runner. Each manufacturer will use their own set of characteristics and every model created by each brand name includes a distinct set of design features that they make use of. The challenge with the suggesting and purchasing running shoes is usually that each and every runner will have a unique foot size and shape and also a distinct method in which the foot functions and exactly how that they run and all of this really needs to be matched up with the proper characteristics of a running shoe to meet their requirements. These types of different attributes include options including the drop, that is the difference between the height of the shoe under the ball of the foot as opposed to the heel. The amount of extra padding in various areas of the running footwear may also change in various footwear and it is yet another variable design attribute. A number of runners require more padding, and some runners need much less. The midsole which is the lower part of the running shoe is one of the features of the running shoe which varies the most. The midsole can be a single density or perhaps dual density.
A dual density characteristic is what is referred to as a medial post. This is where there is a increased density substance inside the midsole about the medial aspect of the midsole only. The shoe's medial posting was first introduced back in 1984 in the X-Caliber GT running shoe that later became the ASICS Gel Kayano. The original purpose of this medial post characteristic was as one of a number of motion control design options within running footwear to manage ‘overpronation‘ with the foot in the athlete. In those days ‘overpronation’ was thought to be a problem for athletes. This is where the foot toll inwards excessively at the ankle joint, so it does make some common sense that the running shoes be more dense in that medial portion of the midsole to try and end this. However, the evidence of the medial posting actually being capable of doing that is not very good. The reason for this is that this medial posting could have varying effects on various runners and just how effectively that it functions is determined by just what is causing this ‘overpronation’. This is also according to the presumption that something has to be done about the ‘overpronation’, which is not always the case. In some athletes, this medial posting is very valuable since it may shift the center of ground reaction forces medially. This may adjust lever arms across the joints in the foot and some clinicians find that significantly useful in the management of some runners’ concerns.
Medial posting being a design feature that is used in running shoes is being used much less now and several manufacturers have stopped using it. That is a shame because it still may have practical uses in certain athletes which will take advantage of it. It's not necessarily going to be of much use to those athletes which don't need it.