Fitrim: Wheelchair power to the people

Technology that makes people move!

To launch new projects that use the possibilities of technology in order to make people move, TU Delft Sports Engineering Institute and TU Delft Health Initiative have joint forces in a Combined health and sports idea accelerator.

Sport and physical activity stimulate a healthy lifestyle in every life stage. It stimulates physical and mental development with children, prevents adults from developing lifestyle related diseases, connects people of all ages and supports elderly to stay active longer. But sport also connects and supports an inclusive society where everyone can live active lives, unhindered by age, condition, gender or background. One of the major challenges of this time is to stimulate people to engage in physical activity in order to achieve physical and mental health. Technology can play a key role in the engagement of people to move more.

One of the projects that received funding is Fitrim: Wheelchair power to the people. Read all about it below.
Want to know about the other project that received funding? Read about it here.

Fitrim: Wheelchair power to the people

Just imagine that you just drove your wheelchair for half an hour over bumpy roads and some grassy spots, only to have your fitbit or smartphone activity tracker inform you that you took only 50 steps, burned virtually no calories and that you shouldn’t be such a couch potato. ‘There has to be a better way,’ Marit van Dijk thought. A seed grant from Delft Health Initiative and the TU Delft Sports Engineering Institute makes the difference.

As a PhD student within the Biomechanical Engineering department (BMechE), Marit van Dijk is mostly engaged in research related to elite wheelchair sports. ‘My predecessor, Rienk van der Slikke, developed software for measuring speed, acceleration and distance travelled by the wheelchair based on two small sensors attached to it,’ she says. ‘It is my task to now also determine the power generated by the person in the wheelchair, and how this relates to an athlete’s performance during training or competition.’

The timing of those moments of contact between hand and push rim appeared important in determining power

A matter of touch

To propel, a wheelchair user will grab a hold of the push rims attached to each of the large wheels and make a forward motion. It turned out that the timing of those moments of contact between hand and push rim appeared important in determining power. ‘So, we developed the RhIDE system, a kind of sleeve with an integrated touch measurement system that needly fits over the push rims,’ Marit says. ‘Combined with the existing sensors, we think this will allow us to unravel the power dynamics. For example, as soon as a wheelchair user lets go of the rims, we can quickly do a deceleration measurement to determine drag resistance – of the wheels on the ground or, perhaps, a headwind. The more resistance, the more power will be needed to accelerate.’ 

Endless possibilities

As soon as Marit, Rienk and her supervisor, professor Veeger, submitted a patent application for the RhIDE system, they immediately wondered about extending its applications. That is where the seed money they won in a grant application of the Delft Health Initiative and the TU Delft Sports Engineering Institute comes in. ‘It provides us the means to build a next prototype and do usability testing,’ she says. ‘Right now, there are endless possibilities, each coming with its own requirements.’ Perhaps only scientists will be interested, in which case it doesn’t have to be a very comfortable system. Or physical therapists may want to use it to monitor their injured patients when they practice a different wheelchair stroke pattern. Marit: ‘I, myself, hope that we can develop it into a smart activity tracker for the everyday wheelchair user.’

Our sleeve with an integrated touch measurement system has endless possibilities


They have already come up with a name for their activity tracker: Fitrim (yes, somewhat analogous to Fitbit). Not only will this provide the largest user base, but it also comes with a wide range of potential applications. An accurate estimate of calories burned, or counting 1000 pushes instead of 10.000 steps, is only the beginning. ‘More than half of the independent wheelchair users develop over-use injuries,’ Marit says. ‘So, by accurately measuring their activity characteristics, we may be able to prevent injuries in the future.’ They are even considering integrating it with a smartphone GPS as well. If sufficient people use Fitrim, it will eventually allow them to provide feedback on wheelchair accessible routes and it may even become a tool used in urban planning.

More than half of the independent wheelchair users develop over-use injuries

A long way

Right now, most of the development is in the hands of students, under the close supervision of Marit and Rienk. But once they know how well then can measure wheelchair power and who will be their end user(s), they could very well decide to apply for a much larger research grant. It shows that a little money goes a long way, and so do plenty of wheelchair users.