Net external energy of the biologic and prosthetic ankle during gait initiation

Hansen, Andrew H.; Miff, Steve C.; Childress, Dudley S.; Gard, Steven A.; Meier, Margrit R.

doi:10.1016/j.gaitpost.2009.08.237

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Volume 31, Issue 1 , Pages 13-17, January 2010

Net external energy of the biologic and prosthetic ankle during gait initiation

Andrew H. Hansen
- Northwestern University Prosthetics Research Laboratory and Rehabilitation Engineering Research Program, Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Jesse Brown VA Medical Center, Department of Veterans Affairs, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
- Corresponding author at: Northwestern University Prosthetics Research Laboratory and Rehabilitation Engineering Research Program, 345 E. Superior Street, Room 1441, Chicago, IL 60611, United States. Tel.: +1 312 238 6500; fax: +1 312 238 6510.
Steve C. Miff
- Department of Biomedical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
- Sg2, Skokie, IL, United States
Dudley S. Childress
- Northwestern University Prosthetics Research Laboratory and Rehabilitation Engineering Research Program, Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
Steven A. Gard
- Northwestern University Prosthetics Research Laboratory and Rehabilitation Engineering Research Program, Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Jesse Brown VA Medical Center, Department of Veterans Affairs, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
Margrit R. Meier
- Northwestern University Prosthetics Research Laboratory and Rehabilitation Engineering Research Program, Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- National Centre of Training and Education in Prosthetics and Orthotics, University of Strathclyde, Glasgow, Scotland, UK

Received 18 December 2008; received in revised form 7 August 2009; accepted 11 August 2009. published online 17 September 2009.

Abstract

The net external energy of the biologic human ankle joint and of some lower limb prosthetic ankle–foot systems was examined during gait initiation. The purpose of the study was to better understand the ankle's behavior during the acceleration phase of walking for use in the design of improved lower limb prostheses and orthoses.

Quantitative gait data were collected from 10 able-bodied subjects and 10 persons with unilateral transtibial amputations during gait initiation. The behaviors of the biologic and prosthetic ‘ankle’ joints were examined by analyzing the relationship between sagittal plane ankle angles and moments. Net external energy at the ankle was estimated by calculating the area under the moment versus angle curves (hysteresis) created during the loading and unloading phases.

Results indicate that able-bodied persons utilize energy input from the trailing ankle after the first step is made in gait initiation, most likely to help transition the body into steady-state walking. The passive prosthetic ankle–foot systems tested were unable to put energy into the system during gait initiation.

Keywords: Prosthetics, Energy, Work