Question: How much does shoe weight affect performance?
Dr. Jack Daniels: As a matter of fact I did the original research on shoe-weight factor, when I was working for Nike in the early 1980s and our research was presented at the World Congress of Sports Medicine in Vienna in the early 1980s. We found adding 100 grams to the shoe increased the aerobic demand of running by 1%. Now 100 grams is about 3.5274 ounces, so each ounce changes the cost of running about 0.2835% (1/3.5274= 0.2835). If you can run a mile in 5:40, that is going 284 meters per minute and that speed of running typically coasts about 55.55 ml O2 per Kg body weight per minute. 1 less ounce will change the cost to about 55.7075 (from 55.55 above) and that VO2 will be associated with a running speed of 284.7 m/min and a mile time of 5:39.17, so about .83 seconds for a mile, per ounce less weight.
NOW, that research involved running in the exact same pairs of shoes with little lead weights inserted into a sleeve sewed onto the sides of the shoe (at the point of center of mass of the shoe so it wouldn’t change the toe or heel drop any). This allowed us to test WEIGHT ADJUSTMENT ONLY. When we tested the aerobic demand of different shoes of different weights, then we found a different story. Basically, as shoe weight went lighter the cost also dropped some, but when the shoe weight went too light, then the cost went up because there was getting to be less midsole cushioning and the runner’s muscles had to start absorbing more landing shock and that costs more energy. It depends on the surface on which you are running. A nice soft artificial track will itself absorb some landing shock so the shoes don’t need to do that for you, but on a street, you need some cushioning and that adds a little weight to the shoe, whereas reducing weight too far actually increases the cost of running, as does the material used in shoe design.