Document Detail

Metabolic cost, mechanical work, and efficiency during walking in young and older men.
MedLine Citation:
PMID:  16497190     Owner:  NLM     Status:  MEDLINE    
AIM: To investigate mechanical work, efficiency, and antagonist muscle co-activation with a view to better understand the cause of the elevated metabolic cost of walking (C(W)) in older adults. METHODS: Metabolic, mechanical and electromyographic measurements were made as healthy young (YOU; n = 12, age = 27 +/- 3 years) and older (OLD; n = 20, age = 74 +/- 3 years) men of equivalent body mass and leg length walked on a treadmill at four speeds (ranging from 0.83 to 1.67 m s(-1)). RESULTS: Net (above resting) C(W), determined by indirect calorimetry was 31% higher (average across speeds) in OLD (P < 0.05). The integrity of the passive pendulum like interchange of mechanical energies of the centre of mass (COM(B)), an energy-saving mechanism, was maintained in OLD. Furthermore, total mechanical work, determined from fluctuations in mechanical energy of COM(B) and of body segments relative to COM(B), was not significantly elevated in OLD. This resulted in a lower efficiency in OLD (-17%, P < 0.05). Co-activation, temporally quantified from electromyography recordings, was 31% higher in OLD for antagonist muscles of the thigh (P < 0.05). Thigh co-activation was moderately correlated with C(W) at three speeds (r = 0.38-0.52, P < 0.05). CONCLUSION: Healthy septuagenarians with no gait impairment have an elevated C(W) which is not explained by an elevation in whole body mechanical work. Increased antagonist muscle co-activation (possibly an adaptation to ensure adequate joint stability) may offer partial explanation of the elevated C(W).
O S Mian; J M Thom; L P Ardigò; M V Narici; A E Minetti
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta physiologica (Oxford, England)     Volume:  186     ISSN:  1748-1708     ISO Abbreviation:  Acta Physiol (Oxf)     Publication Date:  2006 Feb 
Date Detail:
Created Date:  2006-02-24     Completed Date:  2006-09-15     Revised Date:  2009-02-03    
Medline Journal Info:
Nlm Unique ID:  101262545     Medline TA:  Acta Physiol (Oxf)     Country:  England    
Other Details:
Languages:  eng     Pagination:  127-39     Citation Subset:  IM    
Institute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Alsager, UK.
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MeSH Terms
Aging / physiology*
Calorimetry, Indirect
Energy Metabolism / physiology*
Exercise Test / methods
Gait / physiology
Oxygen Consumption / physiology
Walking / physiology*

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