Can You Run 4% Faster?

We already know since the early 80s, 1980s that if you have a heavier shoe, usually when we make it 100 grams heavier, so the shoe on each side, so general shoe is like 250 grams. And then if you add 100 grams to that shoe, you're going to be using 1% more energy. Thus, that mean we can run 4% faster. That was sort of the big question for that study. We wanted to know all of these things we do in a lab, do they actually translate to running faster and by how much?