Carbon super shoes

Super shoes, with a thick, very springy foam and usually a carbon plate, save about 2 to 4 % of energy at the same pace: often 1 to 2 % faster in a race.

• Most of the gain comes from the foam; the plate stiffens the shoe and helps the foot roll forward.
• The benefit is largest at race pace and varies a lot between runners; at slow paces it shrinks.
• Keep them for races and a few key sessions at race pace: their foam wears faster, often after 300 to 500 km.
• Ease in: they shift load to your feet, calves and Achilles, and foot stress fractures have been reported. Begin with short runs and stop if a sharp, localised foot pain appears.