Running on blades at the Paralympics

French athlete Jean Baptiste Alaize. (Valery Hace/Getty Images)

You see them zooming along the track at high speeds. Para runners move on prosthetics (artificial limbs) that look like curved metal blades. Jumpers use them to reach incredible distances.

What are these high-tech devices that let Paralympic athletes run and jump so well?

They're designed like a cheetah leg

Cheetah legs (left). Running blades (right). (Simon Brute for OIS/Getty Images)

Running blades look high-tech. But they don’t use bionics or any sort of motors to move. Their design is based on the natural world.

Designer Van Phillips wanted a prosthetic leg that wouldn’t just allow him to walk, but to run. So, for inspiration, he looked to the fastest runners of all — cheetahs!

He based the blade on the shape of the cheetah’s hind legs. He studied how their long tendons hurtle them forward like catapults (emphasis on the cat).

They work like a bouncing spring

French athlete Jean Baptiste Alaize trains by jumping hurdles. (Valery Hache/Getty Images)

With each downward step, the blade compresses. It then propels the athlete forward with explosive energy, like a bouncing spring.

The blades are made of carbon fibre. That's a super-strong and lightweight material. It's definitely high-tech.

They fit into a socket that covers the remaining part of the athlete’s leg. That cushions and protects them.

Blades made for running

Blake Leeper of the United States races in the 400-metre at the London 2012 Paralympics. (Gareth Copley/Getty Images)

Athletes need to prepare even before they get on their blades. They strengthen the muscles in their torsos. They’ll need those core muscles for balance and to make turns on the track.

Getting used to the blades can be a challenge. They’re great for running but hard to walk or stand on. Running over uneven ground or up and down hills, like for the marathon, is tricky.

Different events need different types of blades too. Blades for sprinting are longer and have more of a 'J' shape.

Long-distance runners usually use a blade that’s shaped more like a 'C.' Detachable spikes are fitted to the bottom of the blades to better grip the track. They can be swapped out when they get worn down.

Blades made for jumping

Japan's Toru Suzuki competes in the high jump at the 2012 London Paralympics. (Eddie Keogh/Reuters)

Para athletes also use blades to compete in jumping events. Their blades have a slightly longer 'toe' in the very front.

They have to be strong enough to handle up to seven times the athlete’s body weight when they land. Like running blades, they have spiked pads on the bottom to grip the track.

Athletes train to find the right rhythm of movement. That way they can run at top speed and then push off from the ground on their blades.

Vanessa Low of Germany competes in the long jump at the 2016 Rio Paralympics. (Jason Cairnduff/Reuters)

Long jumpers have been able to reach distances of eight metres and beyond!