Using sensors to stop sports injuries
All athletes, from amateurs joggers to elite footballers, experience sports injuries. What if medical professionals could predict when those injuries were going to occur and stop the damaging activity before the injury happens? In her PhD research, Annemarijn Steijlen takes a step in that direction.
The road less travelled
Steijlen took an unusual path to her doctorate. She began her studies at the TU Delft | Faculty of Industrial Design Engineering (IDE), obtaining both a bachelor’s degree and a master’s in Integrated Product Design (IPD) before moving on to do her PhD at the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS). “I don’t know anyone else who did this,” she says.
After she completed her master’s degree, she really wanted to pursue something more technical. For her master’s thesis, she had designed an electrocardiogram (ECG) machine that could be used at home and so, her adviser, IDE Professor Kaspar Jansen, encouraged her to look down the road at the Faculty of EEMCS to work more with wearable sensor technology.
Annemarijn found an opening in EEMCS’ electronic instrumentation department working on two research projects: a pair of sensor pants that track the movements of football and hockey players and a sweat collection system designed to explore non-invasive methods of studying electrolytes and other chemicals. Her thesis, ‘Sensor Technology for Unobtrusive Athlete Monitoring’, was supported by three advisers – her master’s adviser from IDE, Kaspar Jansen, as well as Professor Paddy French and Associate Professor Andre Bossche from EEMCS.
Kicking athletic injuries to the curb
For the pants, Steijlen worked with the Royal Dutch Football Association (KNVB) and the Royal Dutch Hockey Association (KNHB) where trainers were concerned about the hamstring and groin injuries their athletes experience. “The doctor for the KNVB asked if we could design something so they could take players out before they get injured,” she says.
![[Translate to English:] Cover of Annemarijn's thesis, with a photo of a male athlete sitting on a chair.](https://filelist.tudelft.nl/IO/Onderzoek/Discover_Design/Annemarijn%20Steijlen/Cover_AS.png)
According to Steijlen, there is a hypothesis that hamstring injuries are the result of an accumulation of explosive movements, like sudden, powerful kicks. Teams see more of these injuries at the end of matches. The outcome of her research, a pair of pants which she refers to as a Smart Sensor Tight, tracks the movements athletes make while playing and allows trainers to see a read out of exactly how their legs moved.
For that project, Steijlen first used existing sensors in lab experiments before moving on to lab studies. Then she conducted systems testing. “We ended up using existing sensors in the final prototype because the technology was already so advanced,” she says.
She handed the pants over to movement scientists at the KNVB Campus, who could then test them on actual athletes. “It went quite far for a research project,” Steijlen says. In the end, she made four versions of the pants, adapting each one to the feedback she received.
![[Translate to English:] Schematical representatino of the design, with layers of materials.](https://filelist.tudelft.nl/IO/Onderzoek/Discover_Design/Annemarijn%20Steijlen/Visuals-01-01.jpg)
Her sweat collection project, on the other hand, took a very different path. She describes it as “a project driven more by curiosity” than the pants, which had a clearer mandate. Information about the physiological status of an athlete is usually obtained from blood samples but drawing blood can be an unpleasant and expensive undertaking. Sweat, however, is significantly easier to obtain. The caveat being, researchers still don’t know a lot about the type of information that can be gathered from the liquid.
According to Steijlen, some scientists say that you can measure stress via sweat, but the research on this is very vague. Thus she focused her efforts on designing a product that could reliably collect and continuously analyse sweat.
To do so, she designed her own sensors, which are attached to an athlete’s back in three spots while they exercise. The information gathered can then be read via a laptop connected to the device. “I hope people use this platform to find out new things about sweat,” Steijlen says.
![[Translate to English:] Athlete on a home trainer with sensors on her body](https://filelist.tudelft.nl/IO/Onderzoek/Discover_Design/Annemarijn%20Steijlen/AnnemarijnSteijlen-IG0NbdFq_4x.jpg)
![[Translate to English:] Three sweat collectors with sensors](https://filelist.tudelft.nl/IO/Onderzoek/Discover_Design/Annemarijn%20Steijlen/IMG_4852with_text.jpg)
Having one foot on either side of campus wasn’t always easy. “It was a real challenge,” she admits. But Steijlen’s expertise in design and her knowledge of electronics was needed for both projects. The sensors had to collect the data and interpret it correctly, while the products had to be comfortable and unobtrusive enough to wear during vigorous activity, like a football match.
According to Steijlen, industrial designers and electrical engineers approach research from very different perspectives. At EEMCS, researchers were quick to jump in to develop the needed technology while at IDE the first step was to explore what the user actually needs. In the end, she says, “It was valuable that I could bring another perspective.”
Given her jump across faculties, it’s not surprising that Steijlen has made another interesting move after successfully defending her PhD thesis. She has begun a post-doctoral position at the University of Antwerp to research a drug monitoring system for customs agents. Their goal is to develop something that can determine, on the spot, if a white power is, for example, amphetamine or cocaine. “It’s very different,” she says.
The images used above have been featured in the following publications: Analytical Chemistry (Anal. Chem. 2022, 94, 18, 6893–6901) and Wearable Technologies (Wearable Technologies , Volume 2 , 2021 , e17).
Annemarijn Steijlen
Kaspar Jansen
- +31 (0) 152786905
- k.m.b.jansen@tudelft.nl
-
Room B-3-170
