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The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days of muscle unloading

Weber, Tobias and Ducos, Michel and Mulder, Edwin and Beijer, Asa and Herrera, F. and Zange, J. and Degens, Hans and Bloch, W. and Rittweger, Jörn (2014) The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days of muscle unloading. Clinical Physiology and Functional Imaging, 34 (3), pp. 218-229. Wiley. doi: 10.1111/cpf.12087. ISSN 1475-0961.

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In the light of the dynamic nature of habitual plantar flexor activity, we utilized an incremental isokinetic exercise test (IIET) to assess the work-related power deficit (WoRPD) as a measure for exercise-induced muscle fatigue before and after prolonged calf muscle unloading and in relation to arterial blood flow and muscle perfusion. Eleven male subjects (31 ± 6 years) wore the HEPHAISTOS unloading orthosis unilaterally for 56 days. It allows habitual ambulation while greatly reducing plantar flexor activity and torque production. Endpoint measurements encompassed arterial blood flow, measured in the femoral artery using Doppler ultrasound, oxygenation of the soleus muscle assessed by near-infrared spectroscopy, lactate concentrations determined in capillary blood and muscle activity using soleus muscle surface electromyography. Furthermore, soleus muscle biopsies were taken to investigate morphological muscle changes. After the intervention, maximal isokinetic torque was reduced by 23·4 ± 8·2% (P<0·001) and soleus fibre size was reduced by 8·5 ± 13% (P = 0·016). However, WoRPD remained unaffected as indicated by an unchanged loss of relative plantar flexor power between pre- and postexperiments (P = 0·88). Blood flow, tissue oxygenation, lactate concentrations and EMG median frequency kinematics during the exercise test were comparable before and after the intervention, whereas the increase of RMS in response to IIET was less following the intervention (P = 0·03). In conclusion, following submaximal isokinetic muscle work exercise-induced muscle fatigue is unaffected after prolonged local muscle unloading. The observation that arterial blood flow was maintained may underlie the unchanged fatigability.

Item URL in elib:https://elib.dlr.de/88834/
Document Type:Article
Title:The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days of muscle unloading
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Weber, TobiasDLR, tobias.weber (at) dlr.deUNSPECIFIED
Mulder, EdwinEdwin.Mulder (at) dlr.deUNSPECIFIED
Beijer, Asaasa.beijer (at) dlr.deUNSPECIFIED
Degens, HansManchester Metropolitan UniversityUNSPECIFIED
Bloch, W.German Sport University CologneUNSPECIFIED
Rittweger, Jörnjoern.rittweger (at) dlr.deUNSPECIFIED
Date:May 2014
Journal or Publication Title:Clinical Physiology and Functional Imaging
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
DOI :10.1111/cpf.12087
Page Range:pp. 218-229
Keywords:arterial blood flow; muscle fatigue; muscle perfusion; muscle power; muscle unloading
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Research under Space Conditions
DLR - Research area:Raumfahrt
DLR - Program:R FR - Research under Space Conditions
DLR - Research theme (Project):R - Vorhaben Effects of Mikro-g und Hyper-g (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Space Physiology
Deposited By: Becker, Christine
Deposited On:15 Apr 2014 09:37
Last Modified:31 Jul 2019 19:46

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