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Delayed myonuclear addition, myofiber hypertrophy, and increases in strength with high-frequency low-load blood flow restricted training to volitional failure.
J Appl Physiol (1985). 2019 03 01; 126(3):578-592.JA

Abstract

The purpose of the present study was to investigate muscle hypertrophy, strength, and myonuclear and satellite cell (SC) responses to high-frequency blood flow-restricted resistance exercise (BFRRE). Thirteen individuals [24 ± 2 yr (mean ± SD), 9 men] completed two 5-day blocks of 7 BFRRE sessions, separated by a 10-day rest period. Four sets of unilateral knee extensions to voluntary failure at 20% of one repetition maximum (1RM) were conducted with partial blood flow restriction (90-100 mmHg). Muscle samples obtained before, during, 3 days, and 10 days after training were analyzed for muscle fiber area (MFA), myonuclei, SC, and mRNA and miRNA expression. Muscle size was measured by ultrasonography and magnetic resonance imaging and strength with 1RM knee extension. With the first block of BFRRE, SC number increased in both fiber types (70%-80%, P < 0.05), whereas type I and II MFA decreased by 6 ± 7% and 15 ± 11% (P < 0.05), respectively. With the second block of training, muscle size increased by 6%-8%, whereas the number of SCs (type I: 80 ± 63%, type II: 147 ± 95%), myonuclei (type I: 30 ± 24%, type II: 31 ± 28%), and MFA (type I: 19 ± 19%, type II: 11 ± 19%) peaked 10 days after the second block of BFRRE, whereas strength peaked after 20 days of detraining (6 ± 6%, P < 0.05). Pax7- and p21 mRNA expression were elevated during the intervention, whereas myostatin, IGF1R, MyoD, myogenin, cyclinD1 and -D2 mRNA did not change until 3-10 days postintervention. High-frequency low-load BFRRE induced robust increases in SC, myonuclei, and muscle size but modest strength gains. Intriguingly, the responses were delayed and peaked 10-20 days after the training intervention, indicating overreaching. NEW & NOTEWORTHY In line with previous studies, we demonstrate that high-frequency low-load blood flow-restricted resistance exercise (HF-BFRRE) can elicit robust increases in satellite cell and myonuclei numbers, along with gains in muscle size and strength. However, our results also suggest that these processes can be delayed and that with very strenuous HF-BFRRE, there may even be transient muscle fiber atrophy, presumably because of accumulated stress responses. Our findings have implications for the prescription of BFR exercise.

Authors+Show Affiliations

Department of Public Health, Sport and Nutrition, Faculty of Health and Sport Sciences, University of Agder , Kristiansand , Norway.Department of Food and Nutrition, and Sport Science, University of Gothenburg , Sweden. Department of Health and Rehabilitation, Unit of Physiotherapy, Institute of Neuroscience and Physiology, University of Gothenburg , Gothenburg , Sweden.Department of Physical Performance, Norwegian School of Sport Sciences , Oslo , Norway.The Norwegian Olympic Federation , Oslo , Norway.Liggins Institute, University of Auckland , New Zealand.Liggins Institute, University of Auckland , New Zealand. Food & Bio-based Products Group, AgResearch, Palmerston North , New Zealand. Riddet Institute , Palmerston North , New Zealand.Department of Physical Performance, Norwegian School of Sport Sciences , Oslo , Norway.Department of Vascular Surgery, Oslo University Hospital , Oslo , Norway.Department of Public Health, Sport and Nutrition, Faculty of Health and Sport Sciences, University of Agder , Kristiansand , Norway.Department of Physical Performance, Norwegian School of Sport Sciences , Oslo , Norway.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30543499

Citation

Bjørnsen, Thomas, et al. "Delayed Myonuclear Addition, Myofiber Hypertrophy, and Increases in Strength With High-frequency Low-load Blood Flow Restricted Training to Volitional Failure." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 126, no. 3, 2019, pp. 578-592.
Bjørnsen T, Wernbom M, Løvstad A, et al. Delayed myonuclear addition, myofiber hypertrophy, and increases in strength with high-frequency low-load blood flow restricted training to volitional failure. J Appl Physiol. 2019;126(3):578-592.
Bjørnsen, T., Wernbom, M., Løvstad, A., Paulsen, G., D'Souza, R. F., Cameron-Smith, D., Flesche, A., Hisdal, J., Berntsen, S., & Raastad, T. (2019). Delayed myonuclear addition, myofiber hypertrophy, and increases in strength with high-frequency low-load blood flow restricted training to volitional failure. Journal of Applied Physiology (Bethesda, Md. : 1985), 126(3), 578-592. https://doi.org/10.1152/japplphysiol.00397.2018
Bjørnsen T, et al. Delayed Myonuclear Addition, Myofiber Hypertrophy, and Increases in Strength With High-frequency Low-load Blood Flow Restricted Training to Volitional Failure. J Appl Physiol. 2019 03 1;126(3):578-592. PubMed PMID: 30543499.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Delayed myonuclear addition, myofiber hypertrophy, and increases in strength with high-frequency low-load blood flow restricted training to volitional failure. AU - Bjørnsen,Thomas, AU - Wernbom,Mathias, AU - Løvstad,Amund, AU - Paulsen,Gøran, AU - D'Souza,Randall F, AU - Cameron-Smith,David, AU - Flesche,Alexander, AU - Hisdal,Jonny, AU - Berntsen,Sveinung, AU - Raastad,Truls, Y1 - 2018/12/13/ PY - 2018/12/14/pubmed PY - 2020/6/18/medline PY - 2018/12/14/entrez KW - Kaatsu KW - ischemic exercise KW - muscle hypertrophy KW - myogenic stem cells KW - myonuclei SP - 578 EP - 592 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J. Appl. Physiol. VL - 126 IS - 3 N2 - The purpose of the present study was to investigate muscle hypertrophy, strength, and myonuclear and satellite cell (SC) responses to high-frequency blood flow-restricted resistance exercise (BFRRE). Thirteen individuals [24 ± 2 yr (mean ± SD), 9 men] completed two 5-day blocks of 7 BFRRE sessions, separated by a 10-day rest period. Four sets of unilateral knee extensions to voluntary failure at 20% of one repetition maximum (1RM) were conducted with partial blood flow restriction (90-100 mmHg). Muscle samples obtained before, during, 3 days, and 10 days after training were analyzed for muscle fiber area (MFA), myonuclei, SC, and mRNA and miRNA expression. Muscle size was measured by ultrasonography and magnetic resonance imaging and strength with 1RM knee extension. With the first block of BFRRE, SC number increased in both fiber types (70%-80%, P < 0.05), whereas type I and II MFA decreased by 6 ± 7% and 15 ± 11% (P < 0.05), respectively. With the second block of training, muscle size increased by 6%-8%, whereas the number of SCs (type I: 80 ± 63%, type II: 147 ± 95%), myonuclei (type I: 30 ± 24%, type II: 31 ± 28%), and MFA (type I: 19 ± 19%, type II: 11 ± 19%) peaked 10 days after the second block of BFRRE, whereas strength peaked after 20 days of detraining (6 ± 6%, P < 0.05). Pax7- and p21 mRNA expression were elevated during the intervention, whereas myostatin, IGF1R, MyoD, myogenin, cyclinD1 and -D2 mRNA did not change until 3-10 days postintervention. High-frequency low-load BFRRE induced robust increases in SC, myonuclei, and muscle size but modest strength gains. Intriguingly, the responses were delayed and peaked 10-20 days after the training intervention, indicating overreaching. NEW & NOTEWORTHY In line with previous studies, we demonstrate that high-frequency low-load blood flow-restricted resistance exercise (HF-BFRRE) can elicit robust increases in satellite cell and myonuclei numbers, along with gains in muscle size and strength. However, our results also suggest that these processes can be delayed and that with very strenuous HF-BFRRE, there may even be transient muscle fiber atrophy, presumably because of accumulated stress responses. Our findings have implications for the prescription of BFR exercise. SN - 1522-1601 UR - https://www.unboundmedicine.com/medline/citation/30543499/Delayed_myonuclear_addition_myofiber_hypertrophy_and_increases_in_strength_with_high_frequency_low_load_blood_flow_restricted_training_to_volitional_failure_ L2 - http://journals.physiology.org/doi/full/10.1152/japplphysiol.00397.2018?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -