Task-specific practice can be beneficial for motor rehabilitation after neurological injury. Unfortunately, high labor demands have limited its clinical acceptance, especially for gait rehabilitation. A number of research teams around the world are testing large robotic devices for assisting treadmill stepping as a means for reducing therapist labor. We propose that powered lower limb orthoses may also have a role in assisting gait rehabilitation. Powered orthoses could assist task specific practice of gait with the long-term goal of improving patients' inherent locomotor capabilities. We present data showing that: (1) pneumatically powered lower limb orthoses can provide substantial mechanical assistance to human walking, (2) powered orthoses can lead to motor adaptation of gait in healthy subjects, and (3) powered lower limb orthoses may have positive benefits during gait rehabilitation.