Changes

Studies have consistently shown that heavier shoes reduce running economy<ref name="LussianaFabre2013"/><ref name="Burkett-1985"/><ref name="Sobhani-2014"/><ref name="Wierzbinski-2011"/>. Each 100g/3.5oz added to the weight of each shoe reduces running economy by about 1%<ref name="Franz-2012"/><ref name="Wierzbinski-2011"/><ref name="Frederick 1985"/><ref name="Frederick-1984"/>. Studies of cushioning and Running Economy have provided conflicting information. I believe this conflict is due to some studies using a cushioned treadmill to compare barefoot and shod conditions. Not surprisingly, if a study uses a cushioned treadmill, the cushioning provided by the shoe does not confer any additional advantage over the barefoot condition. Analyzing the research, I conclude that a well cushioned running shoe can improve Running Economy by an estimated 2-3.5% compared with a weight matched un-cushioned shoe<ref name="Franz-2012"/><ref name="Wierzbinski-2011"/><ref name="Tung-2014"/>. Note that running shoes provide less cushioning in colder temperatures<ref name="DibSmith2005"/>. There are indications that a highly flexible shoe that is modified with a springy carbon fiber plate might be more efficient than a highly flexible shoe on its own<ref name="OhPark2017"/><ref name="Roy-2006"/>.