Effects of resistance training combined with vascular occlusion or hypoxia on neuromuscular function in athletes

Abstract

The aim was to investigate the effects of low-load resistant training combined with vascular occlusion or normobaric hypoxic exposure, on neuromuscular function. In a randomised controlled trial, well-trained athletes took part in a 5-week training of knee flexor/extensor muscles in which low-load resistant exercise (20% of one repetition maximum, 1-RM) was combined with either (1) an occlusion pressure of approximately 230 mmHg (KT, n = 10), (2) hypoxic air to generate an arterial blood oxygen saturation of ~80% (HT, n = 10), or (3) with no additional stimulus (CT, n = 10). Before and after training, participants completed the following tests: 3-s maximal voluntary contraction (MVC₃), 30-s MVC, and an endurance test (maximal number of repetitions at 20% 1-RM, Reps₂₀). Electromyographic activity (root mean square, RMS) was measured during tests and the cross-sectional area (CSA) of the quadriceps and hamstrings was measured pre- and post-training. Relative to CT, KT, and HT showed likely increases in MVC₃ (11.0 ± 11.9 and 15.0 ± 13.1%, mean ± 90% confidence interval), MVC₃₀ (10.2 ± 9.0 and 18.3 ± 17.4%), and Reps₂₀ (28.9 ± 23.7 and 23.3 ± 24.0%). Compared to the CT group, CSA increased in the KT (7.6 ± 5.8) and HT groups (5.3 ± 3.0). KT had a large effect on RMS during MVC₃, compared to CT (effect size 0.8) and HT (effect size 0.8). We suspect hypoxic conditions created within the muscles during vascular occlusion and hypoxic training may play a key role in these performance enhancements.

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

“…Likewise, Manimmanakorn et al [29] observed substantially greater increases in strength (3 s MVC) and muscular endurance (30 s MVC and number of repetitions to failure at 20% 1RM), following 5 weeks of training in the IHRT group than a normoxic control group. Similar results were presented in a subsequent study [121], with a small effect (0.44) for IHRT versus the control condition for 3 s MVC, and moderate effects (0.64 and 0.70) for 30 s MVC and number of repetitions to failure at 20% 1RM between these conditions, respectively. While these data suggest that IHRT can accelerate increases in muscle strength, Friedmann et al [120] observed no significant changes in maximum strength or muscular endurance following such a program.…”

“…control). While all groups demonstrated significantly greater muscle activation during strength and endurance tasks following training, the largest increases were reported in the BFR group [121]. This may suggest that the neuromuscular changes were most influenced by the restriction of blood flow, rather than hypoxia per se.…”

“…While skeletal muscle function and activation has been extensively researched using BFR techniques, only Manimmanakorn et al [121] have reported on the responses of skeletal muscle to resistance exercise in systemic hypoxia. Electrical activity of the knee extensors was assessed during tests of muscular strength and endurance in netball athletes prior to, and following, 5 weeks of low-intensity resistance training with either BFR, systemic hypoxia, or no additional stimulus (i.e.…”

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

“…While the vast majority of BFR research has been conducted using untrained participants, several investigations have also demonstrated muscular benefits from BFR in athletic populations [5,[11][12][13][14][15][16][17]. As these individuals have already achieved a high level of muscular development, low-load resistance training would not normally facilitate such benefits, suggesting that the addition of BFR stimulates these responses.…”

“…Numerous investigations have reported beneficial muscular adaptations to BFR training in athletes [5,11,13,14,16]. Furthermore, these adaptive responses have translated into enhanced performance across a range of athletic tasks, including maximum strength [5,14,16], countermovement jump power [5], maximal and repeated sprint performance [5,13,14], agility performance [14] and an aerobic shuttle run test [14].…”