PURPOSE;: We investigated the effects of acute and chronic repeated-sprint exercise (RSE) on the skeletal muscle mRNA expression and protein abundance/phosphorylation associated with mitochondrial biogenesis. METHODS;: Ten healthy young adults (7 males, 3 females) performed the RSE trial, comprising of three sets of 5 x 4-s maximal sprints on a non-motorised treadmill, with a 20-s recovery between sprints and 4.5 min between sets. After four weeks of repeated-sprint training, three times per week, participants repeated the RSE. A vastus lateralis muscle biopsy was obtained at rest, immediately after, 1h and 4h after RSE, pre- and post-training. Venous blood lactate and glucose were measured at rest and during recovery. Real time RT-PCR and western blot techniques were used to measure mRNA expression and protein abundance, respectively. RESULTS;: Acute RSE increased the phosphorylation of Acetyl-CoA Carboxylase (ACC; 86\%; effect size (ES) 1.4 ± 0.8; p<0.001) and Ca calmodulin-dependent protein kinase II (CaMK II; 69\%; ES 0.7 ± 0.6). Peroxisome proliferator-activated receptor γ, co-activator 1α (PGC-1α; 208\%; ES 1.5 ± 0.7; p<0.001), and nuclear respiratory factor 1 (NRF1; 92\%, ES 0.7 ± 0.8) mRNA expression was increased following RSE. Four weeks of training increased the abundance of PGC-1α protein at rest (33\%, ES 0.9 ± 0.7). CONCLUSION;: Both acute and chronic RSE, despite only 60 s and 12 min of exercise respectively, altered the molecular signalling associated with mitochondrial adaptations and PGC-1α mRNA expression in skeletal muscle. However, the small-tomoderate changes in resting PGC-1α protein abundance after training, together with the absence of changes in aerobic fitness, require further research to understand the functional significance of PGC-1α in response to repeated-sprint exercise.
Repeated sprints alter signalling related to mitochondrial biogenesis in humans.
SERPIELLO, FABIO RUBENS;
2012-01-01
Abstract
PURPOSE;: We investigated the effects of acute and chronic repeated-sprint exercise (RSE) on the skeletal muscle mRNA expression and protein abundance/phosphorylation associated with mitochondrial biogenesis. METHODS;: Ten healthy young adults (7 males, 3 females) performed the RSE trial, comprising of three sets of 5 x 4-s maximal sprints on a non-motorised treadmill, with a 20-s recovery between sprints and 4.5 min between sets. After four weeks of repeated-sprint training, three times per week, participants repeated the RSE. A vastus lateralis muscle biopsy was obtained at rest, immediately after, 1h and 4h after RSE, pre- and post-training. Venous blood lactate and glucose were measured at rest and during recovery. Real time RT-PCR and western blot techniques were used to measure mRNA expression and protein abundance, respectively. RESULTS;: Acute RSE increased the phosphorylation of Acetyl-CoA Carboxylase (ACC; 86\%; effect size (ES) 1.4 ± 0.8; p<0.001) and Ca calmodulin-dependent protein kinase II (CaMK II; 69\%; ES 0.7 ± 0.6). Peroxisome proliferator-activated receptor γ, co-activator 1α (PGC-1α; 208\%; ES 1.5 ± 0.7; p<0.001), and nuclear respiratory factor 1 (NRF1; 92\%, ES 0.7 ± 0.8) mRNA expression was increased following RSE. Four weeks of training increased the abundance of PGC-1α protein at rest (33\%, ES 0.9 ± 0.7). CONCLUSION;: Both acute and chronic RSE, despite only 60 s and 12 min of exercise respectively, altered the molecular signalling associated with mitochondrial adaptations and PGC-1α mRNA expression in skeletal muscle. However, the small-tomoderate changes in resting PGC-1α protein abundance after training, together with the absence of changes in aerobic fitness, require further research to understand the functional significance of PGC-1α in response to repeated-sprint exercise.
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