Ergogenic distance running shoes: how do we think they work and how can we understand them better?

Recently developed shoes that are highly-cushioned and have a curved stiff plate embedded in the midsole are “ergogenic” in that they reduce the rate of metabolic energy required to run at a defined speed. These energy savings are not due to low mass but rather to their foam midsoles which are unusually compliant and resilient. The function of the plate has not yet been elucidated, but evidence is clear that the plate itself does not act as a spring or a teeter-totter. The plate may act synergistically with the foam to create an area-elastic structure, akin to a gymnastics floor. Future studies of ergogenic shoes should: focus on muscle function using EMG and ultrasound, explore footstrike pattern effects, only utilize stiff treadmills, and seek to define a consistent baseline shoe condition for comparison.