Training‐induced acceleration of O2 uptake on‐kinetics precedes muscle mitochondrial biogenesis in humans. Issue 4 (16th January 2013)

• Record Type: Journal Article
• Authors: Zoladz, Jerzy A.; Grassi, Bruno; Majerczak, Joanna; Szkutnik, Zbigniew; Korostyński, Michał; Karasiński, Janusz; Kilarski, Wincenty; Korzeniewski, Bernard
• Is Part Of: Experimental physiology. Volume 98:Issue 4(2013:Apr.)
• Page Start: 883
• Page End: 898
• Publication Date: 2013-01-16
• Subjects: Physiology, Experimental -- Periodicals; 571.0724
• DOI: 10.1113/expphysiol.2012.069443
• Languages: English
• ISSNs: 0958-0670

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The effects of 5 weeks of moderate‐intensity endurance training on pulmonary oxygen uptake kinetics (<inline-graphic xlink:href="ark:/27927/pgg3hkkkj2z" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> on‐kinetics) were studied in 15 healthy men (mean ± SD: age 22.7 ± 1.8 years, body weight 76.4 ± 8.9 kg and maximal <inline-graphic xlink:href="ark:/27927/pgg3hkkkj9t" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> 46.0 ± 3.7 ml kg<sup>−1</sup> min<sup>−1</sup>). Training caused a significant acceleration (<italic>P</italic>= 0.003) of <inline-graphic xlink:href="ark:/27927/pgg3hkkkj7q" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> on‐kinetics during moderate‐intensity cycling (time constant of the 'primary' component 30.0 ± 6.6 <italic>versus</italic> 22.8 ± 5.6 s before and after training, respectively) and a significant decrease (<italic>P</italic>= 0.04) in the amplitude of the primary component (837 ± 351 <italic>versus</italic> 801 ± 330 ml min<sup>−1</sup>). No changes in myosin heavy chain distribution, muscle fibre capillarization, level of peroxisome proliferator‐activated receptor γ coactivator 1α and other markers of mitochondrial biogenesis (mitochondrial DNA copy number, cytochrome <italic>c</italic> and cytochrome oxidase subunit I contents) in the vastus lateralis were found after training. A significant downregulation in the content of the sarcoplasmic reticulum ATPase 2 (SERCA2; <italic>P</italic>= 0.03) and a tendency towards a decrease in SERCA1 (<italic>P</italic>= 0.055) was found after training. The decrease in SERCA1 was positively correlated (<italic>P</italic>= 0.05) with the training‐induced decrease in the gain of the <inline-graphic xlink:href="ark:/27927/pgg3hkkkjgk" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> on‐kinetics (<inline-graphic xlink:href="ark:/27927/pgg3hkkkjbc" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> at steady state/Δpower output). In the early stage of training, the acceleration in <inline-graphic xlink:href="ark:/27927/pgg3hkkkfdx" mimetype="image" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> on‐kinetics during moderate‐intensity cycling can occur without enhanced mitochondrial biogenesis or changes in muscle myosin heavy chain distribution and in muscle fibre capillarization. The training‐induced decrease of the O<sub>2</sub> cost of cycling could be caused by the downregulation of SERCA pumps.</p> </abstract>