1. Institute of Human Movement Sciences and Sport, ETH, 8093 Zurich, Switzerland
2. Sensory-Motor Systems Lab, ETH, Zurich, Switzerland
3. Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
4. Institut für Bewegungs- und Sportgerontologie, Deutsche Sporthochschule Köln, Köln, Germany