Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/75553
Title: Increased oxygen extraction and mitochondrial protein expression after small muscle mass endurance training
Authors: Skattebo, Øyvind
Capelli, Carlo
Rud, Bjarne
Auensen, Marius
Calbet, Jose A.L. 
Hallén, Jostein
UNESCO Clasification: 241106 Fisiología del ejercicio
Keywords: Arteriovenous Oxygen Difference
Blood Flow
Endurance Training
Fick Method
Limitations, et al
Issue Date: 2020
Journal: Scandinavian Journal of Medicine and Science in Sports 
Abstract: When exercising with a small muscle mass, the mass-specific O2 delivery exceeds the muscle oxidative capacity resulting in a lower O2 extraction compared with whole-body exercise. We elevated the muscle oxidative capacity and tested its impact on O2 extraction during small muscle mass exercise. Nine individuals conducted six weeks of one-legged knee extension (1L-KE) endurance training. After training, the trained leg (TL) displayed 45% higher citrate synthase and COX-IV protein content in vastus lateralis and 15%-22% higher pulmonary oxygen uptake ((Formula presented.)) and peak power output ((Formula presented.)) during 1L-KE than the control leg (CON; all P <.05). Leg O2 extraction (catheters) and blood flow (ultrasound Doppler) were measured while both legs exercised simultaneously during 2L-KE at the same submaximal power outputs (real-time feedback-controlled). TL displayed higher O2 extraction than CON (main effect: 1.7 ± 1.6% points; P =.010; 40%-83% of (Formula presented.)) with the largest between-leg difference at 83% of (Formula presented.) (O2 extraction: 3.2 ± 2.2% points; arteriovenous O2 difference: 7.1 ± 4.8 mL· L−1; P <.001). At 83% of (Formula presented.), muscle O2 conductance (DMO2; Fick law of diffusion) and the equilibration index Y were higher in TL (P <.01), indicating reduced diffusion limitations. The between-leg difference in O2 extraction correlated with the between-leg ratio of citrate synthase and COX-IV (r =.72-.73; P =.03), but not with the difference in the capillary-to-fiber ratio (P =.965). In conclusion, endurance training improves O2 extraction during small muscle mass exercise by elevating the muscle oxidative capacity and the recruitment of DMO2, especially evident during high-intensity exercise exploiting a larger fraction of the muscle oxidative capacity.
URI: http://hdl.handle.net/10553/75553
ISSN: 0905-7188
DOI: 10.1111/sms.13707
Source: Scandinavian Journal of Medicine and Science in Sports[ISSN 0905-7188], v. 30(9), p. 1615-1631, (Septiembre 2020)
Appears in Collections:Artículos
Thumbnail
Adobe PDF (1,34 MB)
Show full item record

SCOPUSTM   
Citations

5
checked on Sep 12, 2021

Page view(s)

42
checked on Sep 11, 2021

Download(s)

98
checked on Sep 11, 2021

Google ScholarTM

Check

Altmetric


Share



Export metadata



Items in accedaCRIS are protected by copyright, with all rights reserved, unless otherwise indicated.