Symmorphosis and skeletal muscle <span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">
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- 作者：Jayson R. Gifford ; Ryan S. Garten ; Ashley D. Nelson ; Joel D. Trinity ; Gwenael Layec ; Melissa A. H. Witman ; Joshua C. Weavil ; Tyler Mangum ; Corey Hart ; Cory Etheredge ; et al
- 刊名：The Journal of Physiology
- 出版年：2016
- 出版时间：15 March 2016
- 年：2016
- 卷：594
- 期：6
- 页码：1741-1751
- 全文大小：436.8KB
- ISSN：1469-7793
文摘
The concept of symmorphosis postulates a matching of structural capacity to functional demand within a defined physiological system, regardless of endurance exercise training status. Whether this concept applies to oxygen (O<sub>2sub>) supply and demand during maximal skeletal muscle O<sub>2sub> consumption (<span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span>) in humans is unclear. Therefore, in vitro skeletal muscle mitochondrial <span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> (<sub>Mitosub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span>, mitochondrial respiration of fibres biopsied from vastus lateralis) was compared with in vivo skeletal muscle <span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> during single leg knee extensor exercise (<sub>KEsub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span>, direct Fick by femoral arterial and venous blood samples and Doppler ultrasound blood flow measurements) and whole-body <span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> during cycling (<sub>Bodysub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span>, indirect calorimetry) in 10 endurance exercise-trained and 10 untrained young males. In untrained subjects, during KE exercise, maximal O<sub>2sub> supply (<sub>KEsub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">s:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML" accent="true">Q ̇ span>span>O<sub>2maxsub>) exceeded (462 ± 37 ml kg<sup>−1sup> min<sup>−1sup>, P < 0.05) and <sub>KEsub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> matched (340 ± 22 ml kg<sup>−1sup> min<sup>−1sup>, P > 0.05) <sub>Mitosub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> (364 ± 16 ml kg<sup>−1sup> min<sup>−1sup>). Conversely, in trained subjects, both <sub>KEsub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">s:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML" accent="true">Q ̇ span>span>O<sub>2maxsub> (557 ± 35 ml kg<sup>−1sup> min<sup>−1sup>) and <sub>KEsub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> (458 ± 24 ml kg<sup>−1sup> min<sup>−1sup>) fell far short of <sub>Mitosub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> (743 ± 35 ml kg<sup>−1sup> min<sup>−1sup>, P < 0.05). Although <sub>Mitosub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> was related to <sub>KEsub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> (r = 0.69, P < 0.05) and <sub>Bodysub><span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> (r = 0.91, P < 0.05) in untrained subjects, these variables were entirely unrelated in trained subjects. Therefore, in untrained subjects, <span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> is limited by mitochondrial O<sub>2sub> demand, with evidence of adequate O<sub>2sub> supply, whereas, in trained subjects, an exercise training-induced mitochondrial reserve results in skeletal muscle <span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> being markedly limited by O<sub>2sub> supply. Taken together, these in vivo and in vitro measures reveal clearly differing limitations and excesses at <span data-equation-construct="true" class="math-equation-construct"><span data-equation-image="true" class="math-equation-image">span><span data-equation-mathml="true" class="math-equation-mathml" style="display:none">s:mml="http://www.w3.org/1998/Math/MathML">sub xmlns:w="http://www.wiley.com/namespaces/wiley" xmlns:wiley="http://www.wiley.com/namespaces/wiley/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns="http://www.w3.org/1998/Math/MathML">V ̇ sub>O 2 sub> max sub> span>span> in untrained and trained humans and challenge the concept of symmorphosis as it applies to O<sub>2sub> supply and demand in humans.