1. P Kluding, PT, PhD, is Assistant Professor, Department of Physical Therapy and Rehabilitation Science, School of Allied Health, University of Kansas Medical Center, 3056 Robinson Hall, Mailstop 2002, 3901 Rainbow Blvd, Kansas City, KS 66160 (USA)
2. B Gajewski, PhD, is Associate Professor, Department of Biostatistics, Schools of Medicine and Nursing, University of Kansas Medical Center