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Effects of 21 days of bed rest and whey protein supplementation on plantar flexor muscle fatigue resistance during repeated shortening contractions

Bosutti, A. and Mulder, E. and Zange, J. and Bühlmeier, J. and Ganse, B. and Degens, H. (2020) Effects of 21 days of bed rest and whey protein supplementation on plantar flexor muscle fatigue resistance during repeated shortening contractions. European Journal of Applied Physiology, 120, pp. 969-983. Springer. doi: 10.1007/s00421-020-04333-5. ISSN 1439-6319.

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Purpose Space flight and bed rest (BR) lead to a rapid decline in exercise capacity. Whey protein plus potassium bicarbonate diet-supplementation (NUTR) could attenuate this effect by improving oxidative metabolism. We evaluated the impact of 21-day BR and NUTR on fatigue resistance of plantar flexor muscles (PF) during repeated shortening contractions, and whether any change was related to altered energy metabolism and muscle oxygenation. Methods Ten healthy men received a standardized isocaloric diet with (n = 5) or without (n = 5) NUTR. Eight bouts of 24 concentric plantar flexions (30 s each bout) with 20 s rest between bouts were employed. PF muscle size was assessed by means of peripheral quantitative computed tomography. PF muscle volume was assessed with magnetic resonance imaging. PF muscle force, contraction velocity, power and surface electromyogram signals were recorded during each contraction, as well as energy metabolism (31P nuclear magnetic resonance spectroscopy) and oxygenation (near-infrared spectroscopy). Cardiopulmonary parameters were measured during an incremental cycle exercise test. Results BR caused 10–15% loss of PF volume that was partly recovered 3 days after re-ambulation, as a consequence of fluid redistribution. Unexpectedly, PF fatigue resistance was not affected by BR or NUTR. BR induced a shift in muscle metabolism toward glycolysis and some signs of impaired muscle oxygen extraction. NUTR did not attenuate the BRinduced-shift in energy metabolism. Conclusions Twenty-one days’ BR did not impair PF fatigue resistance, but the shift to glycolytic metabolism and indications of impaired oxygen extraction may be early signs of developing reduced muscle fatigue resistance.

Item URL in elib:https://elib.dlr.de/135085/
Document Type:Article
Title:Effects of 21 days of bed rest and whey protein supplementation on plantar flexor muscle fatigue resistance during repeated shortening contractions
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Bosutti, A.Department of Clinical, Technological and Morphological Sciences, Division of Internal Medicine, University Triest, ItalienUNSPECIFIEDUNSPECIFIED
Mulder, E.German Aerospace Center (DLR), Institute of Aerospace Medicine, Space Physiology, Cologne, GermanyUNSPECIFIEDUNSPECIFIED
Zange, J.UNSPECIFIEDhttps://orcid.org/0000-0003-1822-0952133724695
Degens, H.School of Healthcare Science, Manchester Metropolitan University, Manchester, UKUNSPECIFIEDUNSPECIFIED
Date:4 March 2020
Journal or Publication Title:European Journal of Applied Physiology
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 969-983
Keywords:Spaceflight; Fluid shift; Bed rest; Shortening contraction; Muscle fatigue; Plantar Flexors; Pi; ATP; 31P; nuclear magnetic resonance spectroscopy; Muscle oxygenation
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 Systemphysiologie (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Muscle and Bone Metabolism
Deposited By: Becker, Christine
Deposited On:17 Jun 2020 13:14
Last Modified:25 Apr 2023 12:18

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