Exercise prosthesis to improve life for active amputees

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A world-class research environment, a start-up environment for small and medium-sized enterprises, and a good idea from a Master of Science in Engineering graduate from DTU have resulted in the start-up Levitate, which is now developing the first ‘plug-and-play’ exercise prosthesis.

The exercise prosthesis differs from others in that the foot is made of a composite material that is more flexible than conventional protheses and can be mounted directly on a prosthetic sleeve. In addition, it will be lower priced than similar products, for which you typically need to pay a lump sum of DKK 50-100,000. Levitate’s prosthesis is planned to be available at a small monthly subscription price or a lower lump sum price. It should help give all amputees around the world the opportunity to have a physically active and healthier life.

“When I first heard about the idea of designing exercise prostheses for the benefit of amputees, I had no doubt that I would contribute with my knowledge of composite materials,” says Malte Markussen, who is Development Engineer at DTU Wind Energy.

“With very little effort, I could make an actual impact on society, help a lot of people, reduce costs, and make things smarter. Precisely what we’re here to do. To develop technology for the benefit of society.”

Start-up environment means everything

The collaboration began in December 2019 when Lasse W. Madsen—a leg amputee—contacted DTU for help to develop a prosthetic leg that was lower priced than the products available on the market. At DTU, he established contact with Malte, who works with materials manufacturing and builds prototypes and components in DTU’s Large Scale Facility—a test facility of the highest international standard—where DTU conducts research in the testing of strength and exhaustion of large structures like wind turbine blades for industry.

Malte taught Lasse how to manufacture and process composite components and put him in touch with business developer Thomas Hørdam from the DTU Link incubation environment. From here, Lasse received help to develop and test his running prosthesis in DTU’s workshops and laboratories, and he also received research lessons and good tips from relevant partners acting as sounding boards for materials and composites.

“An incubation environment like DTU Link means everything to entrepreneurs like Lasse. We always begin by identifying the individual entrepreneur’s needs, and—on this basis—we then act as a sounding board for the business idea. We also hold a number of specialist events that can inspire and equip entrepreneurs in different areas,” says Thomas.

“For example, we’ve helped Lasse by entering into a dialogue with him on the idea and clarifying what DTU could help him with. We’ve also matched Lasse up with other start-ups in the same and related fields, which has been to their mutual inspiration.”

Hundreds of marathons

With access to DTU’s facilities, Lasse quickly got started building a model for a composite foot in the prototype workshop. Here he has tested the artificial feet on a test machine to monitor the strength and fatigue of the material. So far, the feet have run hundreds of marathons with a load of several hundreds of kilos on the machine, and Lasse and other leg amputees have run thousands of kilometres wearing a prototype to test the foot in practice.

"When I first heard about the idea of designing exercise prostheses for the benefit of amputees, I had no doubt that I would contribute with my knowledge of composite materials."

Malte Markussen, Development Engineer, DTU Wind Energy

The start-up is now based in the office facilities at DTU Link, where Lasse and his co-founder Andrew C. Whittaker are largely self-reliant in manufacturing composite components. Thanks to Malte, Lasse has been able to draw on the long experience of DTU’s materials research group, which has been working with composites since the 1970s. Malte is now based in the Section of Structural Design and Testing.

Today, composite materials are used in, for example, trains and aircraft—in addition to in wind turbine blades—where it provides lighter and stronger structures. For aircraft, this means that they can carry more passengers and fly longer on the same amount of fuel. For trains, this means that less energy is needed to accelerate.

“Composite is an overall category of materials offering a number of advantages relative to metal. We use it for many things that are typically weight sensitive, exposed to environments that impact the useful life of the material, or repetitive loads. If you apply composite materials wisely, you can use them instead of conventional materials in many niche areas,” says Malte.

“Levitate’s exercise prostheses are a good example, because they must be light, but also really strong. With the help of a smart design and advanced mathematics, we’ve succeeded in developing a competitive alternative, at a fraction of the price.”

Will and drive

Levitate has thus come a big step closer to putting its exercise prosthesis into production. The journey to get this far began already when—at the age of 14—Lasse lost his right leg in a traffic accident. At the time, he was registered for a place in a sports continuation school and was to start nine months later. But like most other amputees, he was told that he could simply forget all about running and physical activity because it is incredibly expensive to invest in components for leg-amputated athletes. However, Lasse acquired a sports prosthesis and started at the sports continuation school, where he participated on equal terms with all other students.

He subsequently created an Instagram profile, where he posted stories of his life as an active runner with a leg prosthesis. Here he got an insight into how many people wanted similar sports equipment, but could not afford it. With Levitate, Lasse has made it easy for leg amputees to get started with being physically active:

“I believe that if you have a good idea, will, and drive, you can get things done. The combination of the knowledge and experience that I’ve accumulated during my studies and my work has meant that I dared take the plunge without knowing what the outcome would be.”

DTU Wind Energys material and components lab have helped a graduate engineer from DTU to the startup company Levitate, developing the first ‘plug-and-play’ sports prosthesis at an affordable price from blade materials.