B. Participants and Protocol

Eighteen subjects (1.71±0.08m, 87.1±17.5kg, 66.5±7.7yr, speed=1.11±0.19m/s) after unilateral TKA participated in this study. The study was approved by the Institutional Review Board at the University of Delaware. Each participant signed an informed consent before commencing protocols. Participants at least six months post-unilateral TKA were recruited (Table I). Each subject conducted a 6-meter walk test to determine a self-selected walking speed. Then, each participant was instructed to walk at a self-selected comfortable walking speed on the instrumented split-belt treadmill for one minute.