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OXYGEN COST DURING TREADMILL WALKING WITH HIP AND KNEE IMMOBILISED
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Charlotte
Elsworth1,2,4 ,
Helen Dawes1,2, Johnny Collett1,2, Ken Howells1,
Roger Ramsbottom1, Hooshang Izadi3 and Cath
Sackley4 |
1Movement Science Group, School of Life Sciences, Oxford Brookes
University, Headington, Oxford, UK
2Rivermead Research Group, Oxford Centre for Enablement, Nuffield Orthopaedic
Centre, Headington, Oxford, UK
3Department of Mathematical Sciences, Oxford Brookes University, Wheatley
Campus, Wheatley, Oxford UK
4General Practice and Primary Care, University of Birmingham, Edgbaston,
Birmingham, UK.
| Received |
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27 September 2005 |
| Accepted |
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10
October 2006 |
| Published |
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15
December 2006 |
©
Journal of Sports Science and Medicine (2006) 5, 640 - 645
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| ABSTRACT |
| The
aim of this study was to determine the effect of immobilising the
knee and hip on the oxygen cost (ml·kg-1·min-1)
to velocity relationship during treadmill walking. The study was a
prospective experimental conducted in a Rehabilitation centre. Ten
healthy individuals, five men and five women, with no gait abnormality
participated. Following familiarisation five men and five women walked
on a treadmill and selected their own, free "comfortable walking
velocity" (SSWS). Subjects then performed an incremental test
at -60 to +60% of SSWS. Individuals later repeated the test with the
knee and hip of one limb immobilised. Samples of expired air were
measured at each velocity and the oxygen cost (ml·kg-1·min-1)
to Froude number (Fr) relationship plotted (where calculation of Fr
normalizes for subjects of differing leg length and acts as an index
of velocity). There was a higher oxygen cost, and lower Fr at SSWS
during immobilised (0.21 ± 0.03 ml·kg-1·min-1;
Fr = 0.12 ± 0. 03) compared with free walking (0.16 ± 0.02 ml·kg-1·min-1;
Fr = 0.18 ± 0.04) (p < 0. 01). Statistical analysis demonstrated
that during immobilised walking an inverse fit (y
= β0 + β1/x) and for free
walking a cubic fit (y
= β0 + β1x + β2x2 + β3x3)
best fitted the data. Hip and knee immobilisation increased the oxygen
cost at SSWS and altered the oxygen cost to Fr relationship. The results
have implications in selecting optimal walking velocities in individuals
with impairments affecting mobility such as hemiplegic gait.
KEY
WORDS: Froude number, oxygen cost, immobilisation, hip, knee,
walking, hemiplegic gait.
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