Efficacy of tourniquet ischemia for strength training with low resistance

Abstract

To investigate the efficacy of ischemia in strength training with low mechanical stress, tourniquet ischemia was utilized in low-resistance training. Five untrained subjects conducted one-legged isometric knee extension training with one leg ischemic (I-leg) and the other non-ischemic (NI-leg). Repeated isometric contractions for 2 s with 3 s relaxation in between were continued for 3 min and conducted 3 days/week for 4 weeks as training. Training resistance was 40% of maximal voluntary contraction (MVC) of respective leg and tourniquet ischemia was applied during I-leg training. MVC in I-leg after 2 weeks (9% gain) and 4 weeks (26% gain) were significantly higher than pre-training value (p < 0.05). A significant increase in maximal rate of torque development in I-leg was observed after 4 weeks (p < 0.05). On the contrary, there was no significant changes in either of the parameters in NI-leg. As a consequence, the differences between legs for both parameters were significant after 2 and 4 weeks (p < 0.05 or p < 0.01). The substantial gain in strength and maximal rate of torque development in I-leg demonstrated the efficacy of tourniquet ischemia during low-resistance training of short duration, and suggested the importance of neuromuscular and/or metabolic activity, other than high mechanical stress, to the adapting responses to strength training.

Exercise with Blood Flow Restriction: An Updated Evidence-Based Approach for Enhanced Muscular Development

“…The BFR technique generally involves application of a tourniquet [34], inflatable cuff [35] or elastic knee wraps [36] at the top of each arm or leg to restrict blood flow into the muscle, and occlude blood flow out of the muscle. While elastic automated cuff systems have been developed and popularized in Japan, it may be more practical to employ inflatable cuffs or simple elastic wraps, particularly when large groups are performing BFR.…”

Hypoxia and Resistance Exercise: A Comparison of Localized and Systemic Methods

“…The BFR technique involves application of a tourniquet [14], inflatable cuff [18] or elastic knee wraps [19] around the proximal end of a limb to occlude distal blood flow, thus inducing a localized hypoxic environment during exercise [20]. Early research utilized occlusive pressures in excess of 200 mmHg [8], though more recent findings have demonstrated beneficial results with pressures as low as 50 mmHg [21].…”

“…Training with BFR (also known as Kaatsu training) is currently promoted as a novel training method that enhances muscle hypertrophy and strength [22]. While the American College of Sports Medicine typically recommends that resistance training intensity exceed 60% 1-repetition maximum (1RM) to induce optimum hypertrophy [23], numerous studies have demonstrated substantial increases in hypertrophy and strength following [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] weeks of BFR training at intensities as low as 20% 1RM [21,[24][25][26]. Although the precise mechanisms are not yet clear, the augmented responses to resistance exercise with BFR are believed to be accounted for by a greater accumulation of metabolites and concomitant increases in anabolic hormone concentrations, intramuscular signalling, intracellular swelling and motor unit recruitment [8,12,18].…”

“…Several authors have reported increased peak torque and maximal rate of torque development across a range of angular velocities following low-intensity (20-50% 1RM) BFR training, despite no significant changes in control groups performing the equivalent training without BFR [13,14,25,26]. These increases in strength are likely due to concomitant increases in muscle fibre CSA and neural adaptations.…”

“…The use of a hypoxic stimulus during resistance exercise was initially studied via blood flow restriction (BFR) techniques [8,13,14]. More recently, devices that create a systemic hypoxic environment via nitrogen dilution or oxygen extraction have been used [15][16][17].…”