title: Resistance exercise enhances the molecular signaling of mitochondrial biogenesis induced by endurance exercise in human skeletal muscle.
abstract: Combining endurance and strength training (concurrent training) may change the adaptation compared with single mode training. However, the site of interaction and the mechanisms are unclear. We have investigated the hypothesis that molecular signaling of mitochondrial biogenesis after endurance exercise is impaired by resistance exercise. Ten healthy subjects performed either only endurance exercise (E; 1-h cycling at ∼65% of maximal oxygen uptake), or endurance exercise followed by resistance exercise (ER; 1-h cycling + 6 sets of leg press at 70-80% of 1 repetition maximum) in a randomized cross-over design. Muscle biopsies were obtained before and after exercise (1 and 3 h postcycling). The mRNA of genes related to mitochondrial biogenesis [(peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1)α, PGC-1-related coactivator (PRC)] related coactivator) and substrate regulation (pyruvate dehydrogenase kinase-4) increased after both E and ER, but the mRNA levels were about twofold higher after ER (P < 0.01). Phosphorylation of proteins involved in the signaling cascade of protein synthesis [mammalian target of rapamycin (mTOR), ribosomal S6 kinase 1, and eukaryotic elongation factor 2] was altered after ER but not after E. Moreover, ER induced a larger increase in mRNA of genes associated with positive mTOR signaling (cMyc and Rheb). Phosphorylation of AMP-activated protein kinase, acetyl-CoA carboxylase, and Akt increased similarly at 1 h postcycling (P < 0.01) after both types of exercise. Contrary to our hypothesis, the results demonstrate that ER, performed after E, amplifies the adaptive signaling response of mitochondrial biogenesis compared with single-mode endurance exercise. The mechanism may relate to a cross talk between signaling pathways mediated by mTOR. The results suggest that concurrent training may be beneficial for the adaptation of muscle oxidative capacity.
authors.affiliation: The Åstrand Laboratory of Work Physiology, GIH, The Swedish School of Sport and Health Sciences, Box 5626, 114 86 Stockholm, Sweden.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Henrik
authors.initials: H
authors.lastname: Mascher
authors.forename: Niklas
authors.initials: N
authors.lastname: Psilander
authors.forename: Eva
authors.initials: E
authors.lastname: Blomstrand
authors.forename: Kent
authors.initials: K
authors.lastname: Sahlin
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006360:Heat-Shock Proteins / Q000235:genetics; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D001678:Organelle Biogenesis; D010084:Oxidation-Reduction; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010766:Phosphorylation; D010807:Physical Endurance / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D012333:RNA, Messenger / Q000235:genetics; D055070:Resistance Training / Q000379:methods; D015398:Signal Transduction / Q000235:genetics* / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
chemical_list: D015415:Biomarkers; D006360:Heat-Shock Proteins; C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D012333:RNA, Messenger; D014157:Transcription Factors; C111264:peroxisome-proliferator-activated receptor-gamma coactivator-1; C546842:MTOR protein, human; D017346:Protein Serine-Threonine Kinases; D058570:TOR Serine-Threonine Kinases