The CAREN: Walk Again

ReLoop: Walk Again

The CAREN is an advanced hardware and software system for registration, evaluation and training of functional human behaviour. One of these impressive machines is located at the Military Rehabilitation Center Doorn and is developed by Motek Medical.

ReLoop is an application that stimulates the patient to make steps in specific ways, without them consciously focusing on walking. With every step a part of a virtual, abstract environment is revealed, motivating patients to keep on walking.

The Dutch Department of Defence asked us to design and develop an application for CAREN that is capable of changing a patient’s walking pattern or helping redevelop his or her ability to walk by making a fully immersive experience. Help them temporarily forget they are rehabilitating and give the therapist full, but indirect control over patients exercises.



The CAREN consists of a flexible plateau in where a treadmill is build. This plateau can tilt, yaw and move up and down. Because of this you can simulate for example walking up a mountain or a bumpy road. In front of the plateau is a 180 degrees projection placed which can show a 3D environment. infrared (IR) cameras placed all around the plateau. Lots of very reflective dots are strategically attached to the rehabilitant to reflect the IR light back to the cameras. These dots are so bright on the captured image that they can be separated from the surrounding environment. This can be used to analyse the walking movements.

The Application: ReLoop

ReLoop puts the patient in an abstract and colorful world and each new step illuminates the environment around him. The more the player plays the more music and visual rich the world gets.


ReLoop In-Game ScreenshotReLoop In-Game Screenshot

While walking may be nothing special to anyone that is not physically impaired, it’s an exhaustive effort for someone with – for example – a prosthesis or a cognitive impairment. To develop his or her ability to walk, we took ‘step by step’ literally; with each step the patient takes, a light beam appears in the direction the step was taken.

Lightbeam in Action

Hitting certain checkpoints with this light beam reveals parts of the world, so hitting these functions as a reflection of how the patient is doing. These checkpoints can be placed in specific patterns in real-time by the therapists thus steering the way the patient takes his step.

Julien Ranzijn – Interaction Design & Programming
Remco Meinsma – Coordination
Rob van Duinen – Interaction Design & Concept
Justin Grupper – 3D and Concept Artist
Glenn Verheij – Environment Artist

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Julien Ranzijn Interaction Designer
Julien Ranzijn Interaction Designer