Introduction: Endurance exercise activates mitochondrial biogenesis in skeletal muscle and, on the other hand, does not induce noticeable activation of muscle protein synthesis. Moreover, high intensive endurance exercise activates catabolism in skeletal muscle by up regulation of the ubiquitin-proteasome pathway. On the contrary, strength exercise up regulates muscle protein synthesis. The aim of the study was to investigate the effect of endurance exercise followed by short strength exercise on regulation of mitochondrial biogenesis, protein synthesis, and degradation in human skeletal muscle. Methods: Seven amateur endurance trained males carried out two test sessions: endurance exercise (70 min) and endurance exercise (70 min) followed by short strength exercise session (4 x 12 75% of 1RM) in randomized order. Blood insulin and cortisol levels were evaluated before exercise session and during 2 h of recovery. Biopsy samples from m.vastus lateralis were taken before, 40 min, 5 h and 21 h after termination of endurance exercise. Expression of metabolic (PGC-1a, TFMs) and catabolic (Myostatin, Atrogin-1, MuRF) genes were evaluated by real-time PCR. Expression of anabolic and catabolic signaling regulators (p70, EF2 and FOXO1) as well as PGC-1alpha in cytoplasmic and nuclear fraction were measured by Western blot. Results: Blood hormone levels did not differ between groups before and after exercise sessions. The expression of metabolic genes increased after both exercise sessions and no differences between trials were found for metabolic genes, as well as for PGC-1alpha protein content. The activation of catabolic pathways was more pronounced after endurance exercise compared to combined endurance and strength exercise session. Discussion: The combined endurance and strength exercise session induced changes in mitochondrial biogenesis similar to those after endurance exercise alone. Short strength exercise session might be used for suppression of catabolic response after acute endurance exercise.
© Copyright 2014 19th Annual Congress of the European College of Sport Science (ECSS), Amsterdam, 2. - 5. July 2014. Published by VU University Amsterdam. All rights reserved.