1. Spaulding Rehabilitation Hospital, Charlestown, Massachusetts, USA.
2. Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA.
3. Shirley Ryan AbilityLab, Max Nader Center for Rehabilitation Technologies and Outcomes Research, Chicago, Illinois, USA.
4. UMass Chan Medical School, University of Massachusetts, Worcester, Massachusetts, USA.
5. Department of Physical Therapy, Boston University, Boston, Massachusetts, USA.
6. Department of Integrative Biology and Physiology, University of California–Los Angeles, Los Angeles, California, USA.
7. SpineX Inc., Northridge, California, USA.
8. Department of Physical Therapy, University of Florida, Gainesville, Florida, USA.
9. Department of Biostatistics, University of Florida, Gainesville, Florida, USA.