Human-Machine System for the H2 Lower Limb Exoskeleton

Inclusion Criteria:

* Sub-acute or chronic stroke i.e., interval of at least 3 months or interval of at least 6 months from stroke to time of enrollment, respectively;
* Cognitive ability to assimilate and participate actively in the treatment protocol (Mini Mental State Examination score \> 24 points, out of a total 30 indicating normal cognitive ability);
* Modified Rankin scale scores 2-4 (Mild-Moderate functional disability post-stroke);
* Modified Ashworth Scale of Spasticity score \<= 2 (ranges from 0-4 with 4 reflecting maximum spasticity);
* Have no skin integrity issues;
* Sufficient passive range of motion at the hip (at least 90 deg flexion, 15-20 deg extension), knee (90 deg flexion, complete extension) and ankle (15 deg dorsiflexion, 15 deg plantarflexion);
* Have no contraindications to standing or walking; able to stand with assistive device for at least 5 minutes, and able to walk with assistive device for 10 m.

Exclusion Criteria:

* Severe cognitive and/or visual deficit;
* Hemineglect (determined based on medical record or initial clinical assessment);
* Severe sensory deficit;
* Joint contractures of any extremity that limits normal range of motion during ambulation with assistive devices;
* Skin lesions that may hinder or prevent the application of exoskeleton;
* Uncontrolled angina;
* Severe chronic obstructive pulmonary disease;
* Other medical contraindications; any medical co-morbidities that would prevent standard rehabilitation.

Inclusion criteria for healthy, able-bodied participants:

* Able to understand and sign the consent form
* Age 18-75 years

Exclusion criteria for healthy, able-bodied participants:

\- History of neurological, neuromuscular or physical disability.