Pedro Fatela1, Joana F Reis2, Goncalo V Mendonca2, Janne Avela3, Pedro Mil-Homens2. 1. Faculdade de Motricidade Humana, CIPER, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Lisboa, Portugal. pedrofatela@gmail.com. 2. Faculdade de Motricidade Humana, CIPER, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Lisboa, Portugal. 3. Department of Biology and Physical Activity, Neuromuscular Research Center, University of Jyvaskyla, Jyvaskyla, Finland.
Abstract
PURPOSE: There is some evidence that muscular activation during exercise is enhanced by higher levels of blood flow restriction (BFR). However, the impact of different relative levels of BFR on the acute neuromuscular response to resistance exercise is not yet fully understood. We examined the acute effects of low-intensity knee extensions [20 % of 1-repetition maximum (1RM)] with BFR on muscle activation, neuromuscular fatigue and torque in the rectus femoris (RF) and vastus medialis (VM) muscles. METHODS: Fourteen men (24.8 ± 5.4 years) exercised at 20 % 1RM combined with 40, 60 and 80 % BFR. Restrictive pressures were calculated based on direct blood-flow measurements taken at rest on each participant. Torque was determined during pre- and post-exercise maximal voluntary contractions. Surface electromyographic activity [root mean square (RMS)] was obtained during dynamic and sustained isometric contractions before and after exercise. The median frequency (MF) of the electromyographic power spectrum was computed for isometric contractions. RESULTS: Torque only decreased in the 80 % BFR condition (-5.2 %; p < 0.01). Except for the VM in the 40 % BFR, MF decreased in both muscles post-exercise in all conditions (p < 0.01). MF decrements were of greater magnitude post-exercise at higher levels of BFR. RMS increased within all sets in both muscles (p < 0.01) and attained higher values in the 80 % BFR condition; except for set 1 in the RF muscle (p < 0.01). CONCLUSION: Muscular activation, as well as neuromuscular fatigue, varies as a function of relative BFR intensity. Therefore, the individual determination of vascular restriction levels is crucial before engaging in BFR exercise.
PURPOSE: There is some evidence that muscular activation during exercise is enhanced by higher levels of blood flow restriction (BFR). However, the impact of different relative levels of BFR on the acute neuromuscular response to resistance exercise is not yet fully understood. We examined the acute effects of low-intensity knee extensions [20 % of 1-repetition maximum (1RM)] with BFR on muscle activation, neuromuscular fatigue and torque in the rectus femoris (RF) and vastus medialis (VM) muscles. METHODS: Fourteen men (24.8 ± 5.4 years) exercised at 20 % 1RM combined with 40, 60 and 80 % BFR. Restrictive pressures were calculated based on direct blood-flow measurements taken at rest on each participant. Torque was determined during pre- and post-exercise maximal voluntary contractions. Surface electromyographic activity [root mean square (RMS)] was obtained during dynamic and sustained isometric contractions before and after exercise. The median frequency (MF) of the electromyographic power spectrum was computed for isometric contractions. RESULTS: Torque only decreased in the 80 % BFR condition (-5.2 %; p < 0.01). Except for the VM in the 40 % BFR, MF decreased in both muscles post-exercise in all conditions (p < 0.01). MF decrements were of greater magnitude post-exercise at higher levels of BFR. RMS increased within all sets in both muscles (p < 0.01) and attained higher values in the 80 % BFR condition; except for set 1 in the RF muscle (p < 0.01). CONCLUSION: Muscular activation, as well as neuromuscular fatigue, varies as a function of relative BFR intensity. Therefore, the individual determination of vascular restriction levels is crucial before engaging in BFR exercise.
Authors: Jeremy P Loenneke; Daeyeol Kim; Christopher A Fahs; Robert S Thiebaud; Takashi Abe; Rebecca D Larson; Debra A Bemben; Michael G Bemben Journal: Muscle Nerve Date: 2015-05 Impact factor: 3.217
Authors: Daniel R Moore; Kirsten A Burgomaster; Lee M Schofield; Martin J Gibala; Digby G Sale; Stuart M Phillips Journal: Eur J Appl Physiol Date: 2004-08 Impact factor: 3.078
Authors: Stefanos Karanasios; Charikleia Koutri; Maria Moutzouri; Sofia A Xergia; Vasiliki Sakellari; George Gioftsos Journal: Sports Health Date: 2021-09-13 Impact factor: 4.355
Authors: Goncalo V Mendonca; Carolina Vila-Chã; Carolina Teodósio; André D Goncalves; Sandro R Freitas; Pedro Mil-Homens; Pedro Pezarat-Correia Journal: Eur J Appl Physiol Date: 2021-05-12 Impact factor: 3.078
Authors: Michael J Ilett; Timo Rantalainen; Michelle A Keske; Anthony K May; Stuart A Warmington Journal: Front Physiol Date: 2019-08-13 Impact factor: 4.566
Authors: Jennifer Prue; Dylan P Roman; Nicholas G Giampetruzzi; Arthur Fredericks; Adel Lolic; Allison Crepeau; J Lee Pace; Adam P Weaver Journal: Int J Sports Phys Ther Date: 2022-04-02