- 1. Pregnant or lactating females 2. Spinal cord injury level higher than T4 3. Severe muscle stiffness/tightness 4. Significant spasticity (Modified Ashworth Scale score of 3 or above) 5. Trunk or lower extremity pressure ulcer 6. Open Wounds 7. Unstable spine, un-healed limbs, or fractures 8. Severe sensitivity to touch 9. Presence of bone in soft tissue where bone normally does not exist (heterotopic ossification), limiting range of motion in the hip or knee joints 10. Joint instability, dislocation, moderate to severe hip dysplasia 11. Significant scoliosis (>40 degrees) 12. Hardware, implant, or any external device impeding with safe fitting or use of Phoenix 13. Femoral or tibial rotation deformity (>15 degrees) 14. Significant flexion contractures limited to 35º at the hip and 20º at the knee 15. Uncontrolled seizures, musculoskeletal injury, fracture or lower-limb surgery in past year.