Effects of the transition time between muscle-tendon stretch and shortening on mechanical efficiency.

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Serval ID
serval:BIB_8AD4E65AB7C2
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Effects of the transition time between muscle-tendon stretch and shortening on mechanical efficiency.
Journal
European journal of applied physiology
Author(s)
Henchoz Y., Malatesta D., Gremion G., Belli A.
ISSN
1439-6319
Publication state
Published
Issued date
2006
Peer-reviewed
Oui
Volume
96
Number
6
Pages
665-71
Language
english
Notes
Publication types: Journal Article - Publication Status: ppublish
Abstract
The net mechanical efficiency of positive work (eta(pos)) has been shown to increase if it is immediately preceded by negative work. This phenomenon is explained by the storage of elastic energy during the negative phase and its release during the subsequent positive phase. If a transition time (T) takes place, the elastic energy is dissipated into heat. The aim of the present study was to investigate the relationship between eta(pos) and T, and to determine the minimal T required so that eta(pos) reached its minimal value. Seven healthy male subjects were tested during four series of lowering-raising of the body mass. In the first series (S (0)), the negative and positive phases were executed without any transition time. In the three other series, T was varied by a timer (0.12, 0.24 and 0.56 s for series S (1), S (2) and S (3), respectively). These exercises were performed on a force platform sensitive to vertical forces to measure the mechanical work and a gas analyser was used to determine the energy expenditure. The results indicated that eta(pos) was the highest (31.1%) for the series without any transition time (S (0)). The efficiencies observed with transition times (S (1), S (2) and S (3)) were 27.7, 26.0 and 23.8%, respectively, demonstrating that T plays an important role for mechanical efficiency. The investigation of the relationship between eta(pos) and T revealed that the minimal T required so that eta(pos) reached its minimal value is 0.59 s.
Keywords
Adult, Biomechanics, Elasticity, Energy Metabolism, Humans, Muscle Contraction, Muscle, Skeletal, Muscles, Tendons, Time Factors
Pubmed
Web of science
Open Access
Yes
Create date
28/01/2008 13:17
Last modification date
01/10/2019 7:18
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