Enhancing Voluntary Motion in Broad Patient Populations With Modular Powered Orthoses

Inclusion criteria for able-bodied, young participants will be:

* Aged between 18 to 65 years
* Weigh less than 250 lbs due to limitations in the design of the orthoses
* Ability to lift and lower a 10 kg weight using the neutral-spine squat technique for 10 repetitions

Exclusion criteria for able-bodied, young adult participants will be:

* Pregnant (self-report)
* Any significant neuromuscular or musculoskeletal disorder that would interfere with the study
* Prior history of chronic lower-back pain
* Unable to walk for 20 minutes
* History of any cardiovascular, vestibular, or visual diseases and/or impairments that may interfere with the study
* Cognitive deficits that would impair their ability to give informed consent or impair their ability to follow simple instructions during the experiments. Cognitive deficits will be determined by a Mini-Mental State Examination (MMSE) score of \<22.
* Adults with a known allergy to medical grade tape

Inclusion criteria for elderly participants will be:

* Aged between 65 to 85 years
* Weigh less than 250 lbs due to limitations in the design of the orthoses
* Ability to walk 6 minutes without assistance from a person (may use walking aid)

Exclusion criteria for elderly participants will be:

* Pregnant (self-report)
* Significant pain due to arthritis or other joint problems that would limit their ability to walk
* Any recent lower-extremity fracture (within 3 months)
* Significant neurological (e.g., stroke), orthopedic, or cardiovascular disorder that may affect the ability to walk
* Advised by a physician not to walk or exercise
* Uncontrolled hypertension or diabetes
* Cognitive deficits or visual impairment that would impair their ability to give informed consent or impair their ability to follow simple instructions during the experiments. Cognitive deficits will be determined by a Mini-Mental State Examination (MMSE) score of \<22.
* Adults with a known allergy to medical grade tape