Effect of lower limb muscle fatigue induced by high-level isometric contractions on postural maintenance and postural adjustments associated with bilateral forward-reach task
Autor: | Eric Yiou, M. Mezaour, S. Le Bozec, A.M. Heugas |
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Přispěvatelé: | Complexité, Innovation, Activités Motrices et Sportives (CIAMS), Université Paris-Sud - Paris 11 (UP11)-Université d'Orléans (UO) |
Jazyk: | angličtina |
Rok vydání: | 2009 |
Předmět: |
Dorsum
Adult Male medicine.medical_specialty Posture Biophysics Isometric exercise Electromyography Postural control Leg muscle Upper Extremity 03 medical and health sciences 0302 clinical medicine Physical medicine and rehabilitation Lower limb muscle Isometric Contraction Task Performance and Analysis medicine Humans Orthopedics and Sports Medicine [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph] Analysis of Variance medicine.diagnostic_test business.industry [SCCO.NEUR]Cognitive science/Neuroscience Rehabilitation [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph] 030229 sport sciences Biomechanical Phenomena Lower Extremity Muscle Fatigue business 030217 neurology & neurosurgery |
Zdroj: | Gait and Posture Gait and Posture, Elsevier, 2009, 29 (1), pp.97-101. ⟨10.1016/j.gaitpost.2008.07.003⟩ |
ISSN: | 0966-6362 |
Popis: | International audience; This study tested the effect of lower limb muscle fatigue induced by series of high-level isometric contractions (IC) on postural adjustments and maintenance of erect posture. Subjects (N=7) displaced a bar (grasp-bar) forward with both hands at maximal velocity towards a target ("bilateral forward-reach" task, BFR), before and after a procedure designed to induce fatigue in dorsal leg muscles. This procedure included IC at 60% of maximum. Postural joint and grasp-bar motion, along with electrical activity of postural and focal muscles were recorded. Integrated electromyographical (EMG) activity per 20 ms period ranging from 400 ms before BFR onset (t0) to 400 ms after t0 was compared before and after the fatiguing procedure. This time-window included "anticipatory", "on-line" and "corrective" postural adjustments, i.e. those postural adjustments occurring before (APAs), during (OPAs) and after (CPAs) BFR, respectively. In contrast to the literature, results showed that the fatiguing procedure had no effect on muscle excitation or timing in any of the recorded postural muscles, regardless of APA, OPA or CPA-related time-window. Therefore, the postural drive did not change with fatigue. Furthermore, the peak-to-peak motion at postural joints did not change. Postural maintenance was therefore not additionally challenged. These results are in line with the hypothesis that the effect of fatigue on postural adjustments is dependent on the adequacy between fatigued motor units (MUs) and MUs recruited during the postural adjustments. Increasing IC intensity during the fatiguing procedure might therefore not necessarily exacerbate the effect of fatigue on postural control highlighted during lower level IC. |
Databáze: | OpenAIRE |
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