The long-term goal of this project is to develop prosthetic foot technology that can function differently for different activities. Although current prostheses can be very effective for particular tasks (e.g. walking, running, or standing), an amputee must choose a single prosthesis to achieve reasonably good performance across all daily activities. This results in a compromise, because the biomechanical demands of walking, for example, are different from those for standing. A prosthetic foot that can modulate its mechanical properties to biomechanically accommodate each activity could be very helpful. This prosthesis is intended for use by subjects with amputation of both traumatic and non-traumatic origin. The proposed biomechanical behavior is to modulate foot stiffness differently for many activities, most notably walking and standing. During walking, the prosthesis needs to provide strong weight support to prevent hard landings on the intact leg. This behavior is facilitated by high stiffness. During standing, different users may desire a stable base of support or a compliant foot with large range of motion. The ideal stiffness for each task also depends on the differing demands of dynamic and static stability. Based on studies of gait mechanics, stiffness should be adjusted for each different task.
The Specific Aims of this project are to: 1.To design and construct a prosthetic foot that modulates its mechanical stiffness under automatic computer control based on the user's activity, and test its mechanical characteristics such as stiffness, adjustability, and fast modulation. 2. To perform proof-of-concept testing of the prototype prosthetic foot's effect on walking and standing in amputees.

Public Health Relevance

The most common mobility issues for lower limb amputees are discomfort, stability and fatigue. Persons wearing prosthetic feet find it uncomfortable to stand for long periods or to walk more than moderate distances. These issues are in part due to the fact that walking and standing, and other tasks, all have different biomechanical demands, which must be addressed by a single prosthetic foot. We propose to develop a computer-controlled prosthetic foot that can automatically change its mechanical stiffness depending on the user's task. The prosthetic foot is intended to improve stability and comfort for standing, and reduce impact forces on the leg during walking, and to automatically vary its characteristics during daily life. Such technology may improve comfort and reduce fatigue for amputees. It is intended for use by subjects with amputation of both traumatic and non-traumatic etiology.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Small Business Innovation Research Grants (SBIR) - Phase I (R43)
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Musculoskeletal Rehabilitation Sciences Study Section (MRS)
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Quatrano, Louis A
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Intelligent Prosthetic Systems, LLC
Ann Arbor
United States
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Glanzer, Evan M; Adamczyk, Peter G (2018) Design and Validation of a Semi-Active Variable Stiffness Foot Prosthesis. IEEE Trans Neural Syst Rehabil Eng 26:2351-2359
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Huang, Tzu-wei P; Shorter, Kenneth A; Adamczyk, Peter G et al. (2015) Mechanical and energetic consequences of reduced ankle plantar-flexion in human walking. J Exp Biol 218:3541-50
Ojeda, Lauro V; Rebula, John R; Kuo, Arthur D et al. (2015) Influence of contextual task constraints on preferred stride parameters and their variabilities during human walking. Med Eng Phys 37:929-36