Why are ostriches excellent runners?

We all know that ostriches are excellent runners but looking at them doesn't exactly reveals highly athletic look about them, and they in fact look ungainly.

Ostriches use half the energy that we humans need at our top running speed but they use this energy far more efficiently than we do, and their main secret when it comes to running is their springiness because ostrich tendons store twice as much elastic energy per step than humans do.

Ostriches and humans use nearly exactly the same amount of mechanical work to "swing" their limbs back and forth when running but the advantage the ostriches have over us is in elasticity of their joints.

Professor Jonas Rubenson, from the University of Western Australia's School of Sport Science, Exercise and Health, said that "Ostriches generate over twice as much power from recoil of elastic energy stored in tendons than humans, which means they need less muscle power to run at the same speed, and that moving with elastic limbs is akin to bouncing on a 'pogo stick', where you don't have to work very hard to bounce along - so it's all in the spring of their step."

Ostrich can run at maximum speeds of about 70 km/h (45 mph), which is the top land speed of any bird. Also, contrary to popular belief, ostriches do not bury their heads in sand.

In some African countries (South Africa for instance), people still race each other on the back of Ostriches. The Ostriches are ridden in the same way as horses with special saddles, reins, and bits. However, they are much harder to manage than horses.