Substantial and Reproducible Individual Variability in Skeletal Muscle Outcomes in the Cross-Over Designed Planica Bed Rest Program.

Autor: Fernandez-Gonzalo R; Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden., McDonnell AC; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia., Simpson EJ; MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom., Macdonald IA; MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom., Rullman E; Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden., Mekjavic IB; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.; Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
Jazyk: angličtina
Zdroj: Frontiers in physiology [Front Physiol] 2021 Jul 16; Vol. 12, pp. 676501. Date of Electronic Publication: 2021 Jul 16 (Print Publication: 2021).
DOI: 10.3389/fphys.2021.676501
Abstrakt: To evaluate the individual responses in skeletal muscle outcomes following bed rest, data from three studies (21-day PlanHab; 10-day FemHab and LunHab) were combined. Subjects ( n = 35) participated in three cross-over campaigns within each study: normoxic (NBR) and hypoxic bed rest (HBR), and hypoxic ambulation (HAMB; used as control). Individual variability (SD IR ) was investigated as √(SD Exp 2 -SD Con 2 ), where SD Exp and SD Con are the standard deviations of the change score (i.e., post - pre) in the experimental (NBR and HBR) and the control (HAMB) groups, respectively. Repeatability and moderators of the individual variability were explored. Significant SD IR was detected for knee extension torque, and thigh and calf muscle area, which translated into an individual response ranging from 3 to -17% for knee extension torque, -2 to -12% for calf muscle area, and -1 to -8% for thigh muscle area. Strong correlations were found for changes in NBR vs. HBR (i.e., repeatability) in thigh and calf muscle area ( r = 0.65-0.75, P < 0.0001). Change-scores in knee extension torque, and thigh and calf muscle area strongly correlated with baseline values ( P < 0.001; r between -0.5 and -0.9). Orthogonal partial least squares regression analysis explored if changes in the investigated variables could predict calf muscle area alterations. This analysis indicated that 43% of the variance in calf muscle area could be attributed to changes in all of the other variables. This is the first study using a validated methodology to report clinically relevant individual variability after bed rest in knee extension torque, calf muscle area, and (to a lower extent) thigh muscle area. Baseline values emerged as a moderator of the individual response, and a global bed rest signature served as a moderately strong predictor of the individual variation in calf muscle area alterations.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2021 Fernandez-Gonzalo, McDonnell, Simpson, Macdonald, Rullman and Mekjavic.)
Databáze: MEDLINE
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