Document Detail

Comparison of stimulation patterns for FES-cycling using measures of oxygen cost and stimulation cost.
MedLine Citation:
PMID:  16298543     Owner:  NLM     Status:  MEDLINE    
AIM: The energy efficiency of FES-cycling in spinal cord injured subjects is very much lower than that of normal cycling, and efficiency is dependent upon the parameters of muscle stimulation. We investigated measures which can be used to evaluate the effect on cycling performance of changes in stimulation parameters, and which might therefore be used to optimise them. We aimed to determine whether oxygen cost and stimulation cost measurements are sensitive enough to allow discrimination between the efficacy of different activation ranges for stimulation of each muscle group during constant-power cycling. METHODS: We employed a custom FES-cycling ergometer system, with accurate control of cadence and stimulated exercise workrate. Two sets of muscle activation angles ("stimulation patterns"), denoted "P1" and "P2", were applied repeatedly (eight times each) during constant-power cycling, in a repeated measures design with a single paraplegic subject. Pulmonary oxygen uptake was measured in real time and used to determine the oxygen cost of the exercise. A new measure of stimulation cost of the exercise is proposed, which represents the total rate of stimulation charge applied to the stimulated muscle groups during cycling. A number of energy-efficiency measures were also estimated. RESULTS: Average oxygen cost and stimulation cost of P1 were found to be significantly lower than those for P2 (paired t-test, p<0.05): oxygen costs were 0.56+/-0.03l min-1 and 0.61+/-0.04l min-1 (mean+/-S.D.), respectively; stimulation costs were 74.91+/-12.15 mC min-1 and 100.30+/-14.78 mC min-1 (mean+/-S.D.), respectively. Correspondingly, all efficiency estimates for P1 were greater than those for P2. CONCLUSION: Oxygen cost and stimulation cost measures both allow discrimination between the efficacy of different muscle activation patterns during constant-power FES-cycling. However, stimulation cost is more easily determined in real time, and responds more rapidly and with greatly improved signal-to-noise properties than the ventilatory oxygen uptake measurements required for estimation of oxygen cost. These measures may find utility in the adjustment of stimulation patterns for achievement of optimal cycling performance.
K J Hunt; C Ferrario; S Grant; B Stone; A N McLean; M H Fraser; D B Allan
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Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article     Date:  2005-11-18
Journal Detail:
Title:  Medical engineering & physics     Volume:  28     ISSN:  1350-4533     ISO Abbreviation:  Med Eng Phys     Publication Date:  2006 Sep 
Date Detail:
Created Date:  2006-06-12     Completed Date:  2006-10-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9422753     Medline TA:  Med Eng Phys     Country:  England    
Other Details:
Languages:  eng     Pagination:  710-8     Citation Subset:  IM    
Centre for Rehabilitation Engineering, Department of Mechanical Engineering, University of Glasgow, and Queen Elizabeth National Spinal Injuries Unit, Southern General Hospital, 1345 Govan Road, Glasgow G51 4TF, UK.
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MeSH Terms
Biomedical Engineering
Electric Stimulation Therapy / instrumentation,  methods*,  statistics & numerical data
Exercise Test / instrumentation,  statistics & numerical data
Middle Aged
Models, Biological
Muscle Contraction / physiology
Oxygen / physiology
Paraplegia / physiopathology,  therapy
Spinal Cord Injuries / physiopathology*,  therapy*
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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