Studies show that for every 100 grams (about 3.5 oz) shaved off your shoe, running economy improves by approximately 1 percent. The hunt is always on for lighter foams, ways to cut unnecessary material from the midsole, plate, and outsole. However, the effectiveness of carbon shoes varies significantly from shoe to shoe and from runner to runner. But it’s also a running shoe all runners respond to. Puma essentially applied a similar digital modelling approach to its running shoe development.