With over 600 thousand people each year surviving a stroke, it has become the leading cause of serious long-term disability in the United States [1], [2]. The adverse financial and social conditions attributed to stroke have prompted researchers and entrepreneurs to explore the viability of rehabilitation robots. The Powered Ankle Foot Orthosis (PAFO) utilizes robotic tendon technology and supports motion with a single degree of freedom, ankle rotation in the Sagittal plane. Motion capture data, robot sensor data, and functional 6 minute walk data were collected on three stroke subjects. All subjects had some positive changes in their key gait variables while using the PAFO. These changes were more dramatic while harnessed and using a treadmill as opposed to walking over ground. Robot sensor data showed significant improvements on key variables for the three subjects. Motion capture data showed improvements in knee range of motion for subject 1, and the 6 minute walk data showed an increase in distance walked for subjects 1 and 3. Comfort, stability, and robustness proved to be critical design parameters for developing a gait therapy robot capable of collecting repeatable data with low variability.