Rats bred for low aerobic capacity become promptly fatigued and have slow metabolic recovery after stimulated, maximal muscle contractions

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dc.contributor.author Torvinen, Sira
dc.contributor.author Silvennoinen, Mika
dc.contributor.author Piitulainen, Harri
dc.contributor.author Närväinen, Johanna
dc.contributor.author Tuunanen, Pasi
dc.contributor.author Gröhn, Olli
dc.contributor.author Koch, Lauren G.
dc.contributor.author Britton, Steven L.
dc.contributor.author Kainulainen, Heikki
dc.date.accessioned 2012-11-27T07:46:08Z
dc.date.available 2012-11-27T07:46:08Z
dc.date.issued 2012 fi
dc.identifier.citation Torvinen, S., Silvennoinen, M., Piitulainen, H., Närväinen, J., Tuunanen, P., Gröhn, O., . . . Kainulainen, H. (2012). Rats bred for low aerobic capacity become promptly fatigued and have slow metabolic recovery after stimulated, maximal muscle contractions. PLOS ONE, 7 (11), e48345. doi:10.1371/journal.pone.0048345 Retrieved from http://dx.plos.org/10.1371/journal.pone.0048345 fi
dc.identifier.issn 1932-6203
dc.identifier.other TUTKAID_52574
dc.identifier.uri http://hdl.handle.net/123456789/40438
dc.description.abstract AIM. Muscular fatigue is a complex phenomenon affected by muscle fiber type and several metabolic and ionic changes within myocytes. Mitochondria are the main determinants of muscle oxidative capacity which is also one determinant of muscle fatigability. By measuring the concentrations of intracellular stores of high-energy phosphates it is possible to estimate the energy production efficiency and metabolic recovery of the muscle. Low intrinsic aerobic capacity is known to be associated with reduced mitochondrial function. Whether low intrinsic aerobic capacity also results in slower metabolic recovery of skeletal muscle is not known. Here we studied the influence of intrinsic aerobic capacity on in vivo muscle metabolism during maximal, fatiguing electrical stimulation. METHODS. Animal subjects were genetically heterogeneous rats selectively bred to differ for non–trained treadmill running endurance, low capacity runners (LCRs) and high capacity runners (HCRs) (n = 15–19). We measured the concentrations of major phosphorus compounds and force parameters in a contracting triceps surae muscle complex using 31P-Magnetic resonance spectroscopy (31P-MRS) combined with muscle force measurement from repeated isometric twitches. RESULTS. Our results demonstrated that phosphocreatine re-synthesis after maximal muscle stimulation was significantly slower in LCRs (p<0.05). LCR rats also became promptly fatigued and maintained the intramuscular pH poorly compared to HCRs. Half relaxation time (HRT) of the triceps surae was significantly longer in LCRs throughout the stimulation protocol (p≤0.05) and maximal rate of torque development (MRTD) was significantly lower in LCRs compared to HCRs from 2 min 30 s onwards (p≤0.05). CONCLUSION. We observed that LCRs are more sensitive to fatigue and have slower metabolic recovery compared to HCRs after maximal muscle contractions. These new findings are associated with reduced running capacity and with previously found lower mitochondrial content, increased body mass and higher complex disease risk of LCRs. fi
dc.language.iso eng
dc.publisher Public Library of Science
dc.relation.ispartof PLOS ONE
dc.relation.uri http://dx.plos.org/10.1371/journal.pone.0048345
dc.rights © 2012 Torvinen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
dc.rights.uri http://creativecommons.org/licenses/by/2.5/
dc.subject.other aerobinen kapasiteetti
dc.subject.other metaboliset sairaudet
dc.subject.other raajalihas
dc.subject.other supistusominaisuudet
dc.subject.other aerobic capacity
dc.subject.other complex disease
dc.subject.other contractile properties
dc.subject.other skeletal muscle
dc.title Rats bred for low aerobic capacity become promptly fatigued and have slow metabolic recovery after stimulated, maximal muscle contractions fi
dc.type Article en
dc.identifier.urn URN:NBN:fi:jyu-201211273078
dc.subject.kota 315
dc.contributor.laitos Liikuntabiologian laitos
dc.contributor.laitos Department of Biology of Physical Activity en
dc.contributor.oppiaine liikuntafysiologia
jyx.tutka.volyme 7
jyx.tutka.mnumber 11
jyx.tutka.pagetopage e48345
dc.type.uri http://purl.org/eprint/type/JournalArticle
dc.identifier.doi 10.1371/journal.pone.0048345
dc.date.updated 2012-11-27T04:30:34Z
dc.description.version Published version
eprint.status http://purl.org/eprint/type/status/PeerReviewed

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