1. E.M. Poppert, PT, DPT, OCS, Division of Biokinesiology and Physical Therapy, University of Southern California, 1540 E Alcazar St, CHP 155, Los Angeles, CA 90089-9006 (USA).
2. K. Kulig, PT, PhD, FAPTA, Division of Biokinesiology and Physical Therapy, University of Southern California.