Low-Intensity Blood Flow Restriction Resistance Exercise
High–intensity weight training is synonymous with success in bodybuilding. It’s seen as the most effective way for continued muscle hypertrophy. Such weight training typically encompasses lifting a weight of at least 70% of one’s concentric one-repetition maximum (1-RM). It is believed that anything below this intensity does not produce significant muscle growth1. But new research suggests one can still get significant muscle hypertrophy by lifting just 20-30% 1-RM. Sounds crazy? Well it’s not…the only catch is that you have to restrict blood flow to the exercising muscle.
A comprehensive series of studies over the past several years has shown that blood flow restriction combined with low intensity resistance exercise (20–30% concentric 1-RM) can result in skeletal muscle hypertrophy, increased strength, and increased endurance2. Scientists are still trying to establish the exact mechanisms by which blood flow restriction combined with resistance exercise works. Some of the key proposed mechanisms include increased fiber type recruitment, metabolic accumulation, stimulation of muscle protein synthesis, and cell swelling; although it is likely that many of the aforementioned mechanisms work together3.
Practicalities of Blood Flow Restriction Exercise
Practically speaking, blood flow restriction exercise involves applying a wrapping or occlusion device proximal to the muscle being trained. This method of muscle training is most popular in Japan, where it is termed KAATSU-Training. It was pioneered by a Japanese researcher by the name of Dr. Sir Yoshiaki Sato way back in 1966. Since that time special KAATSU-Training bands have been developed, which are a popular tool for rehabilitation and training in Japan. Examples of some of the KAATSU-Training bands are pictured. These bands allow users to modify the occlusion pressure accurately.
Advantages of Low-Intensity Blood Flow Restricted Exercise
The advantage of low-intensity blood flow restricted resistance exercise (LI-BFRRE) is that it can be performed as part of a high-intensity resistance exercise (HI-RE) program to achieve similar gains in muscle strength and mass as a traditional HI-RE-only program. Additionally, LI-BFRRE does not require a long recovery time between training sessions5-7 owing to the very low mechanical stress and minimal muscle damage associated with it5, 8, 9.
Required Amount of Low-Intensity Blood Flow Restricted Exercise
In terms of the amount of LI-BFR resistance exercise required per week, studies suggest that 2-3 sessions may be optimal to stimulate significant muscle growth when performed in conjunction with a HI-RE program3, 4. While on face value, it is hard to understand how a session or two of LI-BFRRE per week could lead to similar gains in muscle mass as HI-RE, it’s also hard to argue with the science. There are now over 20 studies which prove this method of training is effective3. Typically, LI-BFRRE is performed using a higher number of reps per set with shorter rest periods between sets compared with HI-RE.
Muscle Hypertrophy Possible While Walking
Practically speaking, LI-BFR resistance exercise offers a great alternative to the average gym goer who may be not be able to undertake a HI-RE session due to a variety of reasons namely, injury, fatigue or lack of motivation. While the KAATSU-Training bands don’t seem to be readily available in Australia, a simple alternative is to tie a cloth, sock or suitable piece of clothing around your upper arm or thigh with firm pressure. Studies have shown that even walking training can induce muscle hypertrophy and strength gain when it is combined with restriction of blood flow to the muscles10. So all-in all, low-intensity training with blood flow restriction to the exercising muscle may be a potentially useful and safe method to enhance muscle hypertrophy and strength11.
1. ACSM. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc 2009;41:687–708.
2. Loenneke JP, et al. The anabolic benefits of venous blood flow restriction training may be induced by muscle cell swelling. Medical Hypotheses. 2012;78:151–154.
3. Loenneke JP, et al.Low intensity blood flow restriction training: a meta-analysis. Eur J Appl Physiol. 2011 Sep 16. [Epub ahead of print]
4. Yasuda T, et al. Combined effects of low-intensity blood flow restriction training and high-intensity resistance training on muscle strength and size. Eur J Appl Physiol. 2011;111:2525–2533.
5. Abe T, et al. Skeletal muscle size and circulating IGF-1 are increased after two weeks of twice daily ‘‘KAATSU’’ resistance training. Int J Kaatsu Training Res. 2005;1:6–12.
6. Yasuda T, et al. Muscle activation during low-intensity muscle contractions with varying levels of external limb compression. J Sports Sci Med. 2008;7:467–474.
7. Yasuda T, et al. Muscle activation during low-intensity muscle contractions with restricted blood flow. J Sports Sci. 2009;27:479–489.
8. Fujita T, et al. Increased muscle volume and strength following six days of low-intensity resistance training with restricted muscle blood flow. Int J Kaatsu Training Res. 2008;4:1–8.
9. Takarada Y, et al. Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion. J Appl Physiol. 2000;88:61–65.
10. Abe T, Kearns CF, Sato Y. Muscle size and strength are increased following walk training with restricted venous blood flow from the leg muscle, Kaatsu-walk training. J Appl Physiol. 2006;100:1460—1466.
11. Sumide T, et al. Effect of resistance exercise training combined with relatively low vascular occlusion. Journal of Science and Medicine in Sport. 2009;12:107—112.