Optimizing Ankle Exoskeleton Assistance for Walking Across the Life Span

Older adults walk with greater metabolic rates than young adults. Growing evidence suggests that the greater older adult metabolic rates are related to the structural properties of their lower leg tissues. The tendons of the leg of older adults are more compliant than that of young adults. Accordingly, older adult leg tendons stretch more under a given load, such as during walking, causing their muscles to operate at shorter, less optimal lengths, and higher activity levels than the muscles of young adults - a less economical way to produces force. Thus, the investigators seek to examine whether wearing wearable robotic boots (i.e., ankle exoskeletons) could enable muscles to produce force more economically. By adding an exoskeleton in-parallel to the ankle, the investigators hypothesize that older adults will walk with lower whole-body metabolic rate than without the exoskeleton assistance. In this study, the investigators will have both young and older adult participants walk on a treadmill with a commercially available ankle exoskeleton set in multiple assistance modes. During these trials, the investigators will measure the metabolic cost of walking in young and older adults and also take many physiological and biomechanical measurements to help assess how exoskeletons work to reduce walking effort.