Achieving the required functionality of a trans-tibial prosthesis during the stance phase of gait (e.g., shock absorption, close to normal roll-over characteristics, and smooth transition into swing) depends on the "Amputee Independent Prosthesis Properties" (AIPP), defined here as the mechanical properties of the prosthetic components distal to the socket that directly influence the performance of the amputee. Accordingly, if research studies are to inform the design of better prostheses, AIPP must be a primary consideration. Therefore, the objectives of this PhD study were: 1) develop a standardised method of AIPP characterisation, and 2) investigate the effects of AIPP on amputee performance through human performance testing. For the first objective, a modified version of the roll-over shape model, referred to as the Salford AIPP model, was developed in order to characterise the mechanical properties of a trans-tibial prosthesis (i.e., foot and pylon). A custom-built test-rig was built in order to measure the parameters of this model. For the second objective, a series of human performance studies were conducted which measured the biomechanical, physiological, and subjective performance of five amputees during four walking conditions: self-selected walking speed (SSWS) on the level, fast walking speed on the level, SSWS on a 5% grade incline, and SSWS on a 5% grade decline. A custombuilt foot-ankle mechanism allowed for independent modulation of the prosthetic plantar and dorsiflexion stiffness. Four combinations of plantar and dorsiflexion stiffness were tested during each of the four walking conditions. Results indicated that dorsiflexion stiffness is a dominant factor in trans-tibial amputee gait performance and decreased stiffness improved performance (e.g., increased gait symmetry and reduced metabolic energy expenditure). However, future work on identifying effective AIPP for improved gait performance must involve amputee gait simulation, in which results from this study may serve as a means of validation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:529732 |
| Date | January 2010 |
| Creators | Major, Matthew J. |
| Publisher | University of Salford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://usir.salford.ac.uk/26794/ |
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