Comment by nickcoury

Yes, most of the studies show there is a very large individual variation. The original 4% figure and similar studies were an average of something like 1-7% across runners.

Also interestingly, the shoe in this record uses much less carbon than past shoes, both saving weight and allowing even more super foam where much of the energy return comes from. Though there so much variance in shoe design and materials there are only theories on how much comes from the plate vs foam vs stack height vs weight vs other factors.