1. Biomechatronics Group, Massachusetts Institute of Technology, Cambridge, MA, USA
2. Neuromuscular Biomechanics Laboratory, University of Texas, Austin, TX, USA
3. Biomechanics Laboratory, The Orthopedic Specialty Hospital, 5848 South Fashion Blvd, Murray, UT 84107, USA
4. Locomotion Laboratory, University of Colorado, Boulder, CO, USA