by Dr. Brant McCartan
For shoes – too tight or too loose, which is worse? Both! Poorly fitting shoes can cause blisters, calluses, runner’s toe, and many more problems. Shoes that are too big can allow the foot to move too much, causing shear force, or rubbing. Your skin blisters or thickens as a way to protect itself from the motion. Painful blisters and calluses are the most common problems that can result. People who put a lot of miles on their shoes – whether through work or high impact exercise like running – need to take extra care in finding the right fit.
An age old tip on shoe size has been to go with one that allows one thumb’s width between the end of your longest toe and the end of the shoe. I am not sure if this was used by parents back in the day to purchase shoes that would last through the entire school year, or this is a legitimate method. Another trick that I’ve seen employed it to lace up the shoe and kick the ground gently a couple of times, then have someone try and place a fingers width between your heel and the back of the shoe. If the finger slides in and out easily, it is too big.
What I recommend, as well as some prominent sports medicine fellows and past presidents of the academy (Paul Langer and Stephen Pribut were quoted in Runners World), is to try on the shoes on at the end of the day when your feet are more swollen, because they will swell up when you run. Also, go with what is comfortable for you, and wear the socks you run in when trying on a new shoe. Visiting a shoe store that can measure both the length and width of your feet is also recommended.
If the shoe is off a little, there are different lacing patterns and techniques that make the foot more stable or looser depending on your needs. Several blogs are misleading and recommend getting one half size larger than your normal shoe size for your running shoes. I would not jump to this, but would follow the above advice and go with what’s comfortable. Neoprene insoles help with shear force, and if you have orthotic devices, insert these into the shoes as they are being tried on.
How come when you buy a new pair of shoes do you get a blister the first time you wear them, but then after a while you don’t form a blister anymore with the same shoe? Repeated friction results in cellular adaptation, cell proliferation and resultant epidermal (skin) thickening. Socks are also important for preventing blisters. Wicking socks, such as CoolMax, other Merino wool, or synthetic materials are all recommended over cotton based. If you do double-layer, double up when you are finding a new pair of shoes.