Authors: K J Hunt B A Saunders C Perret H Berry D B Allan N Donaldson T H Kakebeeke
Publish Date: 2007/06/09
Volume: 101, Issue: 3, Pages: 277-285
Abstract
Complete lowerlimb paralysis resulting from spinal cord injury precludes volitional leg exercise leading to muscle atrophy and physiological deconditioning Cycling can be achieved using phased stimulation of the leg muscles With training there are positive physiological adaptations and health improvement Prior to training however power output may not be sufficient to overcome losses involved in rotating the legs and little is known about the energetics of untrained paralysed muscles Here we propose efficiency measures appropriate to subjects with severe physical impairment performing cycle ergometry These account for useful internal work ie muscular work done in moving leg mass and are applicable even for very low work rates Experimentally we estimated total work efficiency of ten untrained subjects with paraplegia to be 76 ± 21 mean ± SD This is close to values previously reported for anaesthetised ablebodied individuals performing stimulated cycling exercise but is less than 1/3 of that of ablebodied subjects cycling volitionally Correspondingly oxygen cost of the work 388 ± 139 ml min−1 W−1 was found to be ∼35 times higher This indicates the need for increased power output from paralysed subjects to maximise muscle strength through training and to improve efficiency by determining better methods of stimulating the individual muscles involved in the exerciseSupported by the UK Engineering and Physical Sciences Research Council and the Swiss Paraplegic Foundation We thank Lynsey Duffell Division of Applied Biomedical Research King’s College London Pius Hofer and Helga Lechner Swiss Paraplegic Research Nottwil and Stan Grant formerly of the Faculty of Biomedical and Life Sciences University of Glasgow for their contributions to this study
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