Making movement visible under water
Water is a safe place to move. It carries the body, it takes away the fear of falling, and it gives resistance in every direction. That is why so many people start their recovery in a pool.
But water also hides something. Once a person is under the surface, it is hard to see exactly how they move. Together with our technology partner CONTEMPLAS, we have changed that. The result is the EWAC Medical Aquatic Motion Tracking System.
Why movement under water is hard to follow
A professional at the poolside looks through the water surface. Waves, reflections and light make the view unclear. Seen from above, a leg does not move the way it seems to move. What the professional sees also depends on where they stand and on the light of that day. And nothing of it is recorded, so one session is difficult to compare with another.
Cameras behind the pool wall
The cameras are placed behind the wall of the pool, under water. They record the person from the side, and with a multi-camera set-up from several synchronised angles. The images are clear, and they are always taken from the same fixed position. So every recording of every session is made in the same way.
A tracking system, not only for walking
This is where the software comes in. CONTEMPLAS has been developing video-based motion analysis software for many years, and together we refined it for use under water.
Every movement in the pool can be recorded, played back and compared: exercises, single joints, the way someone pushes off, and of course walking. Recordings from different sessions can be placed next to each other, because they are always made in the same way.
From images to numbers
Walking is one of the applications that is worked out in detail. In the extended configuration the software recognises the stages of the gait cycle automatically, so the moment the foot lands, the moment it lifts and the swing of the leg become clear values, for example step time, step length and the difference between left and right.
Because the software works in the same way every time, the values are consistent and easy to compare. The system records, visualises and documents movement. Every marker, measurement and interpretation is placed by the professional.
Simple to use at the poolside
The system can be operated from a touch screen. The professional starts a recording, plays it back, and shows it on a large screen next to the pool. The person in the water sees their own movement directly. For many people, that is the moment the exercise starts to make sense.
Why we did this with CONTEMPLAS
At EWAC Medical we keep looking for new ways to help people move again. But innovation does not happen by itself. It comes from combining knowledge that already exists in a new way.
We build the pools, the movable floors and the water treatment. CONTEMPLAS develops the software and provides the video system. Neither of us could have made this on our own. That is why we chose them as our technology partner, and why this is a long-term partnership and not a single project.
What comes next
For us, this is a first step. The more we see of how people move in water, the better we can design the pools around them.
We get you moving. Now you can also see it.
Read more
CONTEMPLAS has published a case study about this solution: contemplas.com/en/aquatic-gait-analysis
