In choosing footwear, fit is everything. You may buy a new pair of shoes, not get a good fit, and use them for short runs or races without much problem. But the longer you’ll be wearing them at a time, the more important the fit.
Here’s a trick to help get ensure a good fit.
Rich Schick, a physician’s assistant and ultrarunner, shared that he believes the key to getting the proper size shoe is the insert – often called insoles. “If the foot does not fit the insert, then the shoe will have to stretch to accommodate the difference or there may be excessive room in the shoe, which can lead to blisters and other foot problems.” He thinks there is too much confusion about straight lasts, curved lasts, semicurved lasts, and so on.
Rick suggests, and I agree, that you don’t need to know any of this if you use the insert to fit your shoes. The same holds true for the proper width of shoe. Simply remove the insert from the shoe and place your heel in the depression made for the heel (in the insert). There should be an inch to an inch and a half from the tip of your longest toe to the tip of the insert. None of your toes or any part of the foot should lap over the sides of the insert. If they do, is it because the insert is too narrow or is it because of a curved foot and straight insert or vice versa? The foot should not be more than about a quarter inch from the edges of the insert either. This includes the area around the heel, or the shoe may be too loose. Check to see if the arch of the insert fits in the arch of your foot. Finally, if all the above criteria are met, then try on the shoe. The only remaining pitfalls are tight toeboxes and seams or uppers that rub.
Remember to take into a account the type and thickness of socks you’ll be wearing. If you are going to replace the stock inserts that come with the shoes, make sure to follow this tip.