Jonnie Peacock with his prosthetic limb for This is Engineering DayMuseum of Engineering Innovation
Advanced Prosthetics: Jonnie Peacock's blade
Jonnie Peacock, MBE, is an English amputee track sprinter who won gold at the 2012 Summer Paralympics and 2016 Summer Paralympics, representing Great Britain in the T44 men’s 100 metres events.
The fastest man on one leg wouldn’t be where he is today without the engineers who designed his running blade.
Jonnie Peacock as a young boy playing footballMuseum of Engineering Innovation
Jonnie's Youth
Jonathan (Jonnie) Peacock was born on 28th May 1993 in Cambridge, in the village of Shepreth. At age 5, he contracted meningitis, resulting in the disease killing the tissues in his right leg, which was then amputated just below the knee.
Whilst having his prosthetic leg fitted in hospital, Jonnie asked about playing football and was directed to a Paralympic sports talent day.
Jonnie with David Beckham as a young boyMuseum of Engineering Innovation
Even after winning the blue riband event of the Paralympics in 10.9 seconds, Jonnie claims the greatest day of his life was meeting David Beckham at Euro 2000, aged 7, when he was still recovering from the physical and mental anguish of having his right leg amputated.
Jonnie Peacock on the starting line (2020-10-27)Museum of Engineering Innovation
Prosper
Peacock has won every major medal available with gold at London Paralympics followed by a repeat, four years later, at Rio in 2016.
He ran his first international race at the Paralympic World Cup in Manchester in May 2012 and in June 2012 Peacock set a new 100 metres world record in amputee sprinting at the United States Paralympic track and field trials, recording a time of 10.85 seconds to beat the previous record by 0.06 seconds.
He claimed World Championships gold in 2013 in Lyon. A set back in 2015, due to injury, meant he was unable to defend his title, though he did go on to claim the title at London 2017. And in 2013, Peacock was appointed Member of the Order of the British Empire (MBE) in the New Year Honours List for services to athletics.
Jonnie Peacock on the starting line and his carbon fibre blade showcasing This is Engineering Day (2020-10-27)Museum of Engineering Innovation
Carbon fibre blades allow athletes to perform at higher levels in their sport than would otherwise be possible, and we’re not just talking about recreational jogging or running across the road, we’re talking high impact, explosive, elite athletics sports like those Jonnie competes in.
Before prosthetics were made from composite materials, amputees who wanted to engage with sports would have to use their ‘every-day’ leg, often made from materials not suitable for high impact activities like running and jumping.
The beauty of using composite materials like glass or carbon fibre is that they can be engineered to be strong in some areas and flexible in others, and therefore have the capacity to absorb, control and release the energy stored in the spring.
Jonnie Peacock, Paralympian gold medallist (2020-10-27)Museum of Engineering Innovation
Constructing a Superhuman
First thing’s first, this is not a bionic leg. There are no electronics, sensors or magnets in it. When a runner’s foot hits the ground, the blade compresses like a spring, storing potential energy. It then rebounds to push the runner forward, using up to 90% of the energy stored in the deflecting blade by the runner’s stride.
You might think this gives amputee athletes a head start, but to put it into perspective able-bodied athletes can produce positive power generated by their own muscles, so while the blade is successfully able to mimic how an physiological leg works, it’s not nearly as efficient.
Take a below-the-knee amputee like Jonnie – he is missing an ankle joint, which means he is also missing muscles that would normally power and articulate the joint. The hip joint and knee joint also act as energy absorbers and generators so when you run, the muscles contract and relax.
The blade harnesses that elastic energy when the blade is deformed. When the load is released, the blade releases some of that energy, assisting with the running motion of the athlete.
Jonnie Peacock with his prosthetic limb for This is Engineering Day (2020-10-27)Museum of Engineering Innovation
So how is the blade made?
Jonnie’s prosthesis consists of a number of components – one is the socket, which is the part he fits into, and then the foot module is the blade that bolts on the back of the socket.
The socket (think of it like a sleeve Jonnie’s leg goes into) is what keeps the prosthetic attached to the athlete, and once it’s on a vacuum is created between his skin and the external environment. When Jonnie pushes himself into the socket, air comes out of a one-way valve that then seals it around his knee – connecting him to the prosthesis.
Close up of a carbon fibre blade used for Paralympian racing (2020-10-27)Museum of Engineering Innovation
The composite
Underneath the socket is the carbon fibre blade, which is the composite part of the prosthetic, which bends and is tailored exactly to his weight, activity level and balance.
A composite is a combination of elements. In Jonnie’s blade the composite is made up of carbon fibre fibres that are embedded in a liquid plastic resin that then sets and is moulded into the right shape. Engineers ensure the composite spring is stiff where it needs to be and strong or flexible where it needs to bend.
The blade has been designed to fit perfectly with the joint movements of running and the thickness of the composite, the direction of the weave and the radius of the bend, have helped propel Jonnie to the success he’s has as a Paralympian.
Close up of carbon fibre blades used by Paralympians (2020-10-27)Museum of Engineering Innovation
Ossur
Jonnie’s blade was made by a company called Ossur. For two years Ossur had a team of 40+ people, including many engineers, working on the design and production of the blade.
Two engineering disciplines were involved the creation of Jonnie’s blade: mechanical engineers (with a focus on composites) worked on the hardware and the design of the product and biomedical engineers analysed the equipment and how the blade works when running.
In the six days running up to the Olympics Jonnie called on his team, which included biomedical engineers, to constantly make small tweaks to the height and angle of his blade in relation to his socket. This ensured the fit was perfected ahead of the most important race of his life.
Gudfinna Halldorsdottir, biomedical engineer, developing cutting-edge prosthetic limbs (2020-10-27)Museum of Engineering Innovation
Meet the engineers
Meet Gudfinna Halldorsdottir. Gudfinna is a Biomedical Engineer from Imperial College London and was one of the engineers who worked on Jonnie’s blade. Her job was to test the blades on athletes and measure the biomechanics parameters, analysing them and presenting her findings back to the team.
Jonnie Peacock, Paralympian, holding his carbon fibre blade (2020-10-27)Museum of Engineering Innovation
What does the future hold?
The success Jonnie Peacock has had as a Paralympic athlete shows that innovations in engineering and technology can erase the disparity between amputee and able-bodied athletes.
Jonnie competes in sporting events governed by rules and regulations, with each competitor having to wear the same equipment to ensure fairness. Outside of the sporting world creative engineering can transform amputee mobility in a wide variety of ways.
Blades in the future could be made with varying stiffness, or to morph throughout the phase of the step. Prosthetics could be lighter and directly connected to the skeleton, or power components could even be added.
Through engineering, anything is possible.
2016 Rio Paralympics
Jonnie Peacock in the 100m men's final
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