ORCID Profile
0000-0002-3814-6246
Current Organisations
Luleå University of Technology
,
Beijing Sport University
,
University of British Columbia
,
Karolinska Institutet
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Publisher: Frontiers Media SA
Date: 08-01-2020
Publisher: JMIR Publications Inc.
Date: 21-10-2019
Publisher: American Physiological Society
Date: 15-03-2015
DOI: 10.1152/AJPENDO.00486.2014
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. Thr 389 phosphorylation 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.
Publisher: Elsevier BV
Date: 11-2021
Publisher: JMIR Publications Inc.
Date: 06-11-2017
Publisher: Springer Science and Business Media LLC
Date: 12-09-2020
Publisher: Public Library of Science (PLoS)
Date: 05-11-2014
Publisher: Frontiers Media SA
Date: 03-04-2017
Publisher: Informa UK Limited
Date: 09-2008
Publisher: JMIR Publications Inc.
Date: 06-05-2020
DOI: 10.2196/16716
Publisher: Public Library of Science (PLoS)
Date: 08-2017
Publisher: Frontiers Media SA
Date: 17-05-2018
Publisher: Wiley
Date: 15-09-2020
DOI: 10.1111/SMS.13802
Publisher: Human Kinetics
Date: 08-2023
Abstract: Background : Elite sport is continuously evolving. World records keep falling and athletes from a longer list of countries are involved. Purpose : This commentary was designed to provide insights into present and future trends associated with world-class endurance training based on the perspectives, experience, and knowledge of an expert panel of 25 applied sport scientists. Results : The key drivers of development observed in the past 10–15 years were related to (1) more accessible scientific knowledge for coaches and athletes combined with (2) better integration of practical and scientific exchange across multidisciplinary perspectives within professionalized elite athlete support structures, as well as (3) utilization of new technological advances. Based on these perspectives, we discerned and exemplified the main trends in the practice of endurance sports into the following categories: better understanding of sport-specific demands improved competition execution larger, more specific, and more precise training loads improved training quality and a more professional and healthier lifestyle. The main areas expected to drive future improvements were associated with more extensive use of advanced technology for monitoring and prescribing training and recovery, more precise use of environmental and nutritional interventions, better understanding of athlete–equipment interactions, and greater emphasis on preventing injuries and illnesses. Conclusions : These expert insights can serve as a platform and inspiration to develop new hypotheses and ideas, encourage future collaboration between researchers and sport practitioners, and, perhaps most important, stimulate curiosity and further collaborative studies about the training, physiology, and performance of endurance athletes.
Publisher: Frontiers Media SA
Date: 05-03-2018
Publisher: Frontiers Media SA
Date: 28-01-2021
DOI: 10.3389/FSPOR.2020.546205
Abstract: This study was designed to examine macro-kinematic parameters of six female cross-country skiers during the qualifying, semi-final and final rounds of a 1.1 km sprint competition in classical technique. During each round these skiers were monitored continuously with a single micro-sensor, and their cycle parameters and relative use of these two sub-techniques calculated. Within each round six sections of the course, during which all skiers employed either double pole (DP) or diagonal stride (DS) sub-technique, were chosen for additional analysis. The mean macro-kinematic cycle parameters and relative usage of sub-techniques over the full course did not differ significantly between rounds. On average 54% of the course was covered employing DP and 13% using DS, while 32% was covered utilizing a non-cyclical or irregular technique. With DP, the mean racing speed and cycle rate (CR) on the starting, middle and finishing sections of the course differed significantly, with no differences in mean cycle length (CL) between the last two sections. At the finish, higher DP speed was achieved by increasing CR. On the three hills, where all athletes utilized DS, mean racing speed and CL, but not mean CR, differed significantly. On these sections DS speed was increased by utilizing longer cycles. The in idual skiers utilized a variety of macro-kinematic strategies during different rounds and on different sections of the course, depending on in idual strengths, preferences and pacing strategies, as well as the course topography and tactical interactions with other skiers. Such collection of macro-kinematic data during competitions can help to identify an in idual skier's strengths and weaknesses, guiding the testing of different cycle rates, and lengths on different terrains during training in order to optimize performance.
Publisher: MDPI AG
Date: 19-05-2018
DOI: 10.3390/S18051632
Publisher: Wiley
Date: 13-07-2015
DOI: 10.1096/FJ.15-273474
Abstract: We examined how the stimulatory effect of leucine on the mechanistic target of rapamycin complex 1 (mTORC1) pathway is affected by the presence of the remaining essential amino acids (EAAs). Nine male subjects performed resistance exercise on 4 occasions and were randomly supplied EAAs with leucine, EAAs without leucine (EAA-Leu), leucine alone, or flavored water (placebo control). Muscle biopsies were taken from the vastus lateralis before and 60 and 90 min after exercise. Biopsies were analyzed for protein phosphorylation, kinase activity, protein-protein interactions, amino acid concentrations, and tracer incorporation. Leucine alone stimulated ribosomal protein s6 kinase 1 (S6K1) phosphorylation ∼280% more than placebo and EAA-Leu after exercise. Moreover, this response was enhanced by 60-75% after intake of EAAs compared with that of leucine alone (P < 0.05). Kinase activity of S6K1 reflected that of S6K1 phosphorylation 60 min after exercise, the activity was elevated 3.3- and 4.2-fold with intake of leucine alone and with EAAs, respectively (P < 0.05). The interaction between mammalian target of rapamycin and regulatory-associated protein of mammalian target of rapamycin was unaltered in response to both resistance exercise and amino acid provision. Leucine alone stimulates mTORC1 signaling, although this response is enhanced by other EAAs and does not appear to be caused by alterations in mTORC1 assembly.
Publisher: Frontiers Media SA
Date: 05-09-2017
Publisher: American Physiological Society
Date: 04-2020
Publisher: JMIR Publications Inc.
Date: 30-04-2018
DOI: 10.2196/MHEALTH.9341
Publisher: Frontiers Media SA
Date: 09-03-2016
No related grants have been discovered for Hans-Christer Holmberg.