1. Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zurich; Zurich 8093 Switzerland
2. Department of Biomedical Engineering; Eindhoven University of Technology; P.O. Box 513 Eindhoven MB 5600 The Netherlands
3. Department of Biomedical Engineering; Institute for Complex Molecular Systems, Eindhoven University of Technology; P.O. Box 513 Eindhoven MB 5600 The Netherlands