TY - JOUR
T1 - Cycling with blood flow restriction improves performance and muscle K+ regulation and alters the effect of antioxidant infusion in humans
AU - Christiansen, Danny
AU - Eibye, Kasper Hvid
AU - Rasmussen, Villads
AU - Voldby, Hans Møller
AU - Thomassen, Martin
AU - Nyberg, Michael Permin
AU - Gunnarsson, Thomas Gunnar Petursson
AU - Skovgaard, Casper
AU - Lindskrog, Mads Søgaard
AU - Bishop, David J
AU - Hostrup, Morten
AU - Bangsbo, Jens
N1 - CURIS 2019 NEXS 110
This article is protected by copyright. All rights reserved.
PY - 2019/5/1
Y1 - 2019/5/1
N2 - Key points: Training with blood flow restriction (BFR) is a well-recognized strategy for promoting muscle hypertrophy and strength. However, its potential to enhance muscle function during sustained, intense exercise remains largely unexplored. In the present study, we report that interval training with BFR augments improvements in performance and reduces net K+ release from contracting muscles during high-intensity exercise in active men. A better K+ regulation after BFR-training is associated with an elevated blood flow to exercising muscles and altered muscle anti-oxidant function, as indicated by a higher reduced to oxidized glutathione (GSH:GSSG) ratio, compared to control, as well as an increased thigh net K+ release during intense exercise with concomitant anti-oxidant infusion. Training with BFR also invoked fibre type-specific adaptations in the abundance of Na+,K+-ATPase isoforms (α1, β1, phospholemman/FXYD1). Thus, BFR-training enhances performance and K+ regulation during intense exercise, which may be a result of adaptations in anti-oxidant function, blood flow and Na+,K+-ATPase-isoform abundance at the fibre-type level. Abstract: We examined whether blood flow restriction (BFR) augments training-induced improvements in K+ regulation and performance during intense exercise in men, and also whether these adaptations are associated with an altered muscle anti-oxidant function, blood flow and/or with fibre type-dependent changes in Na+,K+-ATPase-isoform abundance. Ten recreationally-active men (25 ± 4 years, 49.7 ± 5.3 mL kg−1 min−1) performed 6 weeks of interval cycling, where one leg trained without BFR (control; CON-leg) and the other trained with BFR (BFR-leg, pressure: ∼180 mmHg). Before and after training, femoral arterial and venous K+ concentrations and artery blood flow were measured during single-leg knee-extensor exercise at 25% (Ex1) and 90% of thigh incremental peak power (Ex2) with i.v. infusion of N-acetylcysteine (NAC) or placebo (saline) and a resting muscle biopsy was collected. After training, performance increased more in BFR-leg (23%) than in CON-leg (12%, P < 0.05), whereas K+ release during Ex2 was attenuated only from BFR-leg (P < 0.05). The muscle GSH:GSSG ratio at rest and blood flow during exercise was higher in BFR-leg than in CON-leg after training (P < 0.05). After training, NAC increased resting muscle GSH concentration and thigh net K+ release during Ex2 only in BFR-leg (P < 0.05), whereas the abundance of Na+,K+-ATPase-isoform α1 in type II (51%), β1 in type I (33%), and FXYD1 in type I (108%) and type II (60%) fibres was higher in BFR-leg than in CON-leg (P < 0.05). Thus, training with BFR elicited greater improvements in performance and reduced thigh K+ release during intense exercise, which were associated with adaptations in muscle anti-oxidant function, blood flow and Na+,K+-ATPase-isoform abundance at the fibre-type level.
AB - Key points: Training with blood flow restriction (BFR) is a well-recognized strategy for promoting muscle hypertrophy and strength. However, its potential to enhance muscle function during sustained, intense exercise remains largely unexplored. In the present study, we report that interval training with BFR augments improvements in performance and reduces net K+ release from contracting muscles during high-intensity exercise in active men. A better K+ regulation after BFR-training is associated with an elevated blood flow to exercising muscles and altered muscle anti-oxidant function, as indicated by a higher reduced to oxidized glutathione (GSH:GSSG) ratio, compared to control, as well as an increased thigh net K+ release during intense exercise with concomitant anti-oxidant infusion. Training with BFR also invoked fibre type-specific adaptations in the abundance of Na+,K+-ATPase isoforms (α1, β1, phospholemman/FXYD1). Thus, BFR-training enhances performance and K+ regulation during intense exercise, which may be a result of adaptations in anti-oxidant function, blood flow and Na+,K+-ATPase-isoform abundance at the fibre-type level. Abstract: We examined whether blood flow restriction (BFR) augments training-induced improvements in K+ regulation and performance during intense exercise in men, and also whether these adaptations are associated with an altered muscle anti-oxidant function, blood flow and/or with fibre type-dependent changes in Na+,K+-ATPase-isoform abundance. Ten recreationally-active men (25 ± 4 years, 49.7 ± 5.3 mL kg−1 min−1) performed 6 weeks of interval cycling, where one leg trained without BFR (control; CON-leg) and the other trained with BFR (BFR-leg, pressure: ∼180 mmHg). Before and after training, femoral arterial and venous K+ concentrations and artery blood flow were measured during single-leg knee-extensor exercise at 25% (Ex1) and 90% of thigh incremental peak power (Ex2) with i.v. infusion of N-acetylcysteine (NAC) or placebo (saline) and a resting muscle biopsy was collected. After training, performance increased more in BFR-leg (23%) than in CON-leg (12%, P < 0.05), whereas K+ release during Ex2 was attenuated only from BFR-leg (P < 0.05). The muscle GSH:GSSG ratio at rest and blood flow during exercise was higher in BFR-leg than in CON-leg after training (P < 0.05). After training, NAC increased resting muscle GSH concentration and thigh net K+ release during Ex2 only in BFR-leg (P < 0.05), whereas the abundance of Na+,K+-ATPase-isoform α1 in type II (51%), β1 in type I (33%), and FXYD1 in type I (108%) and type II (60%) fibres was higher in BFR-leg than in CON-leg (P < 0.05). Thus, training with BFR elicited greater improvements in performance and reduced thigh K+ release during intense exercise, which were associated with adaptations in muscle anti-oxidant function, blood flow and Na+,K+-ATPase-isoform abundance at the fibre-type level.
KW - Faculty of Science
KW - Blood flow restriction training
KW - Human muscle
KW - Antioxidant
KW - Reactive oxygen species
KW - N-acetylcysteine
KW - Fibre type
KW - Single type
KW - Na+,K+-ATPase
KW - Ion transport
U2 - 10.1113/jp277657
DO - 10.1113/jp277657
M3 - Journal article
C2 - 30843602
SN - 0022-3751
VL - 597
SP - 2421
EP - 2444
JO - Journal of Physiology
JF - Journal of Physiology
IS - 9
ER -