Study will evaluate the use of lower-limb assistive exo-skeletons worn on the ankle and foot. Participants will wear the exo-skeletons and walk in a safe environment. Measurements will be taken to determine how the exo-skeletons affect the pressure on the feet of people with diabetic foot ulcer and how they walk.

Study will evaluate the use of lower-limb assistive exo-skeletons worn on the ankle and foot. Participants will include those with self-described history of Diabetic Foot Ulcer and age-matched healthy volunteers. Participants will wear the exo-skeletons and will be asked to walk 32 feet, and to stand quietly for 30 seconds.

Measurements will be taken to evaluate how the exoskeletons affect how people walk, and will also evaluate the pressure on the bottom of their feet. These measurements will be repeated multiple times to evaluate four different exo-tendon spring rates, and two sets of control shoes.

Exo-skeletons have been shown to reduce the pressure on the bottoms of people's feet and to reduce the effort to walk. This study is necessary to understand the contribution of different levels of exo-skeleton spring force to these effects.

Inclusion Criteria:

• Self-reported history of diabetic foot ulcer

Exclusion Criteria:

• Unable to continuously ambulate/walk ≥ 40 feet without an assistive device, such as a cane or walker
• Signs/symptoms of an infected foot lesion/ulcer as determined by a basic foot exam
• Trans-metatarsal foot amputation or more significant amputation.
• Symptomatic for signs/symptoms of cardiovascular disease as determined from interpretation of the 2017 PAR-Q+ (predicated on participant responses of "yes" indicating symptomatic/unstable medical conditions to page 2 and page 3 of the 2017 PAR-Q)
• Participants will be excluded from this study if they demonstrate pre-participation, or chronic, signs/symptoms of hypoglycemia: Confusion, unusual headache, unusual visual disturbances, self-reported mental dullness, shakiness, self-reported weakness, abnormal sweating, undue nervousness/anxiety, and/or tingling of the mouth, toes, and/or fingers or if they answer yes to question 5b and 5c of the 2017 PAR-Q+ .
• Participants will be temporarily excluded from this study if they are symptomatic for acute illness such as cold or fever. If the participant is symptomatic for acute illness such as cold or fever, participation will be reconsidered upon illness resolution.
• If participants answer yes to question 4a of the 2017 PAR-Q+ and if they demonstrate pre-study participation resting blood pressure < 90/60 mmHg and >140/90 mmHg .