- Research Project
Bicycle racing despite paralysis is now being made possible by the team around Prof. Kenneth Hunt, with the help of electrical muscle stimulation. The team is entering the Cybathlon for the second time in May 2020 with their self-built CybaTrike. This event is a sports competition in which people with disabilities compete using state-of-the-art assistance systems.
The CybaTrike at the Cybathlon
The CybaTrike is a recumbent bike with two front wheels and one rear wheel, built specially for the first Cybathlon in 2016 by the Institute for Rehabilitation and Performance Technology (IRPT). In the Cybathlon, physically impaired people compete in a unique competition with the help of cutting-edge assistance systems. In 2016, the team from BFH picked up the bronze medal in the discipline “bicycle racing with electrical muscle stimulation”. The second edition of the event is set to take place in May 2020, with the IRPT team headed by Prof. Dr. Kenneth Hunt and with rider Julien Jouffroy also taking part again.
Electrical muscle stimulation
The muscles of the paraplegic rider are activated by means of electrical muscle stimulation, or Functional Electrical Stimulation (FES). This works by electrical pulses being applied to the paralysed leg muscles through electrodes attached to the skin. The pulses cause the muscles to contract. This means that even a person in whom the nerve pathways between the brain and leg muscles are interrupted by a spinal cord injury can trigger a movement with the help of an intelligent control device.
One problem is that because the paralysed limbs cannot give any feedback, the rider does not feel when and how much to activate or cease activating the muscles. The timing of the activation is controlled by sensors on the bicycle crank. Thanks to the feedback from these sensors and the pre-set activation positions, the system knows exactly where the legs are and the correct muscles can be stimulated precisely. However, the strength of the stimulation and thus the degree of activation is controlled by the rider himself via a throttle grip on the handlebars.
Better quality of life
The hope is that the combination of FES and cycling will one day find its place in the everyday lives of paraplegics and quadriplegics. A sporting activity of this nature not only trains the muscles, but also preserves bone density and is good for the cardiovascular system. This in turn has a direct health benefit and leads to an improved quality of life for paraplegics.