The fastest para-sprinters, runners with one or no lower limbs, can race 100m in 10 seconds using high-tech running blades. Designers of the blades took inspiration from the world’s fastest land animal: the cheetah. The secret to a cheetah’s speed is the way it can bend and flex its powerful, springy hind legs. The shape of the blades is designed to do the same and propels an athlete forward with maximum power.