1 a Swiss BioMotion Lab, Department of Musculoskeletal Medicine , Centre Hospitalier Universitaire Vaudois and University of Lausanne , Lausanne , Switzerland.
2 b Mechanical Laboratory of Sousse, National Engineering School of Sousse , University of Sousse , Tunisia.
3 c Institute of Microengineering , Ecole Polytechnique Fédérale de Lausanne , Lausanne , Switzerland.