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

Détails

ID Serval
serval:BIB_8AD4E65AB7C2
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Effects of the transition time between muscle-tendon stretch and shortening on mechanical efficiency.
Périodique
European journal of applied physiology
Auteur(s)
Henchoz Y., Malatesta D., Gremion G., Belli A.
ISSN
1439-6319
Statut éditorial
Publié
Date de publication
2006
Peer-reviewed
Oui
Volume
96
Numéro
6
Pages
665-71
Langue
anglais
Notes
Publication types: Journal Article - Publication Status: ppublish
Résumé
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.
Mots-clé
Adult, Biomechanics, Elasticity, Energy Metabolism, Humans, Muscle Contraction, Muscle, Skeletal, Muscles, Tendons, Time Factors
Pubmed
Web of science
Création de la notice
28/01/2008 13:17
Dernière modification de la notice
03/03/2018 19:10
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