If you have watched the Paralympics you might have seen athletes using prosthetic blades.  Some competitors have one blade, like UK Paralympian Jonny Peacock; others have two – like Richard Whitehead who won Gold in the 200m in 2012, breaking a world record.

How do they work?

The curve at the bottom of the blade helps absorb shock when the blade makes contact with the ground, and that curve also acts like a spring to help the wearer move forward.  They often also have spikes on the tip to help with grip

And it’s all to do with two types of energy – kinetic energy and potential energy.  Imagine jumping on a trampoline. The two types of energy are exchanged as you jump up and down, making you travel – Did you know that energy can’t ever be destroyed? – it just changes its form. 

The same physical processes happen when we run and when athletes use prosthetic blades – potential energy is converted to kinetic energy resulting in forward motion.

Science of Springs

Springs always want to return to their original shape and they’ll force the energy used to stretch them out, to snap back again. Prosthetic blades are basically springs which provide the wearer with the potential energy a full-bodied athlete would get from their muscles, tendons and ligaments.

How Are They Made?

They’re often made of carbon fibre which is light and tough. Over 80 thin layers of carbon fibre are glued together, then heated to bond them together. The exact length and shape – and even the design, depends on the athlete.

Carbon fibre’s a man made material made up of microscopic threads which are woven together. It’s stronger than steel!

Playing Fair

Prosthetic blades help athletes run at high speeds so you might wonder – could they beat able-bodied athletes?  And what if some athletes had blades and others didn’t – would that be a fair race?

It’s a good question and one that’s got experts talking. Blades are lighter and so for long distances can help prevent fatigue – but they put different stresses on the body. And add to that, the human leg is much better at converting potential energy to kinetic energy… and the more kinetic energy – the faster you go.

This means whilst the margins are pretty slim, it’s not a clear advantage to have blades. That said, there’s always a debate as the technology is constantly improving.

A History of the Paralympics

Events like the Paralympics have led to an acceleration in the technology used in prosthetics – but how did the event begin?

The Paralympic Games or Paralympics are a periodic series of international multi-sport events involving athletes with a wide range of disabilities. There are Winter and Summer Paralympic Games, which since the 1988 Summer Olympics in Seoul, South Korea, are held almost immediately following the respective Olympic Games.

The Paralympics has grown from a small gathering of British World War II veterans in 1948 to become one of the largest international sporting events by the early 21st century. The Paralympics has grown from 400 athletes with a disability from 23 countries in 1960 to thousands of competitors from over 100 countries at the 2012 Summer Olympics.

Given the wide variety of disabilities that Para athletes have, there are several categories in which the athletes compete. The allowable disabilities are broken down into ten eligible impairment types. These categories are further broken down into classifications, which vary from sport to sport.

Did you know?

• Prosthetic is basically a Greek word. And, if you translate it to English Language, it means ‘addition’.
• A single prosthesis can cost tens of thousands of pounds but 3-D printing technology can change that and reduce the cost.
• Most prosthetic wears are designed using titanium, aluminium and carbon fiber.
• The average prosthesis lasts no more than 5 years. An amputee has to change it after a course of 5 years whether it is worn out or not.
• The oldest prosthetic wear was found in the year 2000 in the city of Cairo. It was a prosthetic toe made of wood and leather and dated back to 3000 years.
• Many amputees feel a phantom limb sensation. It’s a sensation that your limb is still attached to the body when in actuality, it’s not.
• In the UK around 45 thousand people use a prosthetics.
• Currently, there are 2.1 million people living without a limb.

For more information visit The IET.