Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/22908
Appears in Collections:Faculty of Health Sciences and Sport Journal Articles
Peer Review Status: Refereed
Title: Resistance exercise-induced S6K1 kinase activity is not inhibited in human skeletal muscle despite prior activation of AMPK by high-intensity interval cycling
Authors: Apro, William
Moberg, Marcus
Hamilton, David Lee
Ekblom, Bjorn
van, Hall Gerrit
Holmberg, Hans-Christer
Blomstrand, Eva
Contact Email: d.l.hamilton@stir.ac.uk
Keywords: AMPK
concurrent exercise
S6K1
mTORC1
Issue Date: 15-Mar-2015
Publisher: American Physiological Society
Citation: Apro W, Moberg M, Hamilton DL, Ekblom B, van Hall G, Holmberg H & Blomstrand E (2015) Resistance exercise-induced S6K1 kinase activity is not inhibited in human skeletal muscle despite prior activation of AMPK by high-intensity interval cycling, American Journal of Physiology - Endocrinology and Metabolism, 308 (6), pp. E470-E481.
Abstract: Combining endurance and strength training in the same session has been reported to reduce the anabolic response to the latter form of exercise. The underlying mechanism, based primarily on results from rodent muscle, is proposed to involve AMPK-dependent inhibition of mTORC1 signaling. This hypothesis was tested in eight trained male subjects who in randomized order performed either resistance exercise only (R) or interval cycling followed by resistance exercise (ER). Biopsies taken from the vastus lateralis before and after endurance exercise and repeatedly after resistance exercise were assessed for glycogen content, kinase activity, protein phosphorylation, and gene expression. Mixed muscle fractional synthetic rate was measured at rest and during 3 h of recovery using the stable isotope technique. In ER, AMPK activity was elevated immediately after both endurance and resistance exercise (∼90%,P< 0.05) but was unchanged in R. Thr389phosphorylation of S6K1 was increased severalfold immediately after exercise (P< 0.05) in both trials and increased further throughout recovery. After 90 and 180 min recovery, S6K1 activity was elevated (∼55 and ∼110%, respectively,P< 0.05) and eukaryotic elongation factor 2 phosphorylation was reduced (∼55%,P< 0.05) with no difference between trials. In contrast, markers for protein catabolism were differently influenced by the two modes of exercise; ER induced a significant increase in gene and protein expression of MuRF1 (P< 0.05), which was not observed following R exercise only. In conclusion, cycling-induced elevation in AMPK activity does not inhibit mTOR complex 1 signaling after subsequent resistance exercise but may instead interfere with the hypertrophic response by influencing key components in protein breakdown.
Type: Journal Article
URI: http://hdl.handle.net/1893/22908
DOI Link: http://dx.doi.org/10.1152/ajpendo.00486.2014
Rights: The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.
Affiliation: Swedish School of Sport and Health Sciences (GIH)
Swedish School of Sport and Health Sciences (GIH)
Sport
Swedish School of Sport and Health Sciences (GIH)
University of Copenhagen
Mid Sweden University, Sweden
Swedish School of Sport and Health Sciences (GIH)

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