A Blood Flow Restriction Training Primer

Occlusion training advocacy goes back to the 1960s. Today, we understand and appreciate its efficacy much more than we ever did. Here’s why.

No one would argue with any method that would allow you to increase muscle strength and size using less weight and volume of training. It’s called occlusion training, KAATSU training, or blood flow restriction training (BFR).

Antonio Squillante – The Pinnacle of Isolation Training

Occlusion training is probably one of the most effective ways to promote angiogenesis. This noisy, sophisticated word describes nothing but the physiological process of creating new blood vessels from pre-existing capillaries. For lack of better words, it is the process of increasing capillary density within a specific tissue, in this case, muscle.

Without going too much in depth digging through academic papers and peer-reviewed articles, angiogenesis is a process that normally takes place with training. It’s triggered by gene expression and it’s more likely to occur after endurance-based training. Blood flow restriction training, however, seems to trigger this process in a more specific, localized manner by means of resistance training. It’s, in essence, the pinnacle of isolation training for general endurance purposes.

More capillaries available means two things: more oxygen and less waste product during prolonged, aerobic training and/or between bursts of high-intensity anaerobic training. Over the long distance, this means more significant improvements in terms of VO2Max and/or more volume in terms of heavy strength training.

Better VO2Max and higher tonnage ultimately lead to better improvements in strength, power, and endurance. It’s an investment in the body’s physiological resources to create the foundation for a higher level of functional adaptation. As any other process involving tissue re-modeling, occlusion training takes quite a long time to create a long-lasting adaptation. It very well fit in a GPP program for athletes, being the main goal an overall improvement in work capacity. It can, also, be used to improve power endurance later on during the season as it creates a situation of intense acidosis, strategically pre-fatiguing the muscles.

Ted Sloan – BFR is Efficient and Healing

BFR has been proven through many years of trial and error and through recent scholarly studies to be a highly effective means of training the body and muscle. Although BFR can benefit hypertrophy, strength and fibrous tissue repair, a fairly new use has arisen.

Recent studies show BFR can also be highly useful in the ability to positively affect cardiovascular endurance. Through various studies, BFR has been shown to reduce stroke volume and increase heart rate in participants. A significant increase in blood pressure coincides with these previously mentioned factors to help positively affect the cardiovascular system and consequently increase cardiovascular endurance.

However, due to the increase in blood pressure, it is important to be cautious with the subjects exposed to this form of training. Someone with hypertension, would not be a good fit, for example. Obviously, with any form of training, there are many different modalities that can be used.

Studies have been performed on the effects of BFR use through walking and biking. Common protocols are 15 minutes of BFR use on either walking or biking for 2 to 4 times weekly. Just as with lifting weights, it is important to perform submaximal work.

In one study, subjects biked for 15 minute intervals 3 times a week for 8 weeks. This group increased their exercise time to exhaustion by 15.4% and their VO2Max by 6.4% with only a 3.9% increase in time to exhaustion in control groups and a minor decrease in VO2Max by controlled participants.

Muscle hypertrophy and strength gains were extremely minimal or non-existent in the control group, while the BFR group achieved a 5.4% muscle volume increase and a 7.7% increase in leg extension strength. Participants in the walking studies did not experience as much of a strength increase, however, also tended to experience an increase in hypertrophy.

If used properly, BFR can help to reduce the total work required by an athlete when entering the introductory stages of an off-season training program. Often times, the athlete has taken a period of time off from training and requires some basic cardiovascular work in order to return the resting heart rate back to a healthy acceptable level, on top of the oftentimes initial goal of rebuilding some muscle mass.

This simple protocol can be completed by the athlete on their own time with minimal effort. BFR has been proven to help heal the body much more efficiently than traditional strength training, increase hypertrophy more quickly than traditional strength training and also to simultaneously increase cardiovascular endurance when performed under the right conditions and circumstances. There are few protocols that can help to achieve all three of these tasks, especially during 15 minute intervals performed only a few times a week.

Giulio Palau – Adding Volume to Hypertrophy Programs

In an age where there are so many training methods and modalities to choose from, it can be hard to discern fact from fiction or rather, fad from fiction. If recent talk of BFR training has aroused your sense of skepticism I can’t blame you.

At first glance, it seems like another gimmick perpetuated by an industry of seemingly inexhaustible gimmicks and false pretenses. However, after taking a closer look at the literature, I was pleasantly surprised that BFR seems to be quite effective at inducing a variety of favorable training adaptations with low risk and little to no cost.

The basic premise is this: the metabolic stress caused by partially restricting blood flow to the limbs with an external cuff (6 or 7 tightness on a scale of 1-10) during sub-maximal (about 20-30% of 1RM), high volume (around 15-30 reps x 3-5 sets) strength training, can produce similar strength and hypertrophy adaptations as traditional, high-intensity loading.

This is theorized to be a result of the metabolic effect of the accumulation of lactate and the subsequent hypoxic environment created in the working tissues. One of the direct consequences of this type of metabolic stress is a spike in growth hormone or GH, which has been measured as high as 290x baseline after BFR training (as compared to 100x over baseline with traditional strength training).

Much of the hypertrophic effect has been attributed to this hormonal response. However, this doesn’t fully account for measured increases in strength after a period of BFR training (measured in squat and bench strength in one study). This may be explained by the high threshold of motor units recruited as a result of BFR. Typically, the nervous system recruits motor units in proportion to the amount of force required to overcome an external load.

However, the metabolic stress caused by high volume training in general, and BFR in particular training, can “trick” the nervous system into recruiting a high threshold of motor units in the working musculature. These effects have been measured in working tissues both proximal and distal to the external cuff. In other words, BFR training effects both the limbs and the torso.

The end result is a training modality that can produce measurable gains in both strength and size of muscles with low loading and therefore minimal mechanical and neural stress. This can be hugely useful in adding volume to a hypertrophy program without causing inflammation, or in rehabilitating post-op or post injury clients with poor motor recruitment patterns or a low tolerance for mechanical loading. It should be noted, however, that blood flow restriction training is not an alternative to traditional strength training, but rather a supplement to traditional high-intensity loading.

Adaptations of traditional high-intensity training such as neural drive and connective tissue conditioning are important and essential to being strong and healthy. However, BFR training seems to be an effective tool for metabolic and tissue conditioning in addition to strength training or in the special cases where high loads may not be tolerated.

If your sense of skepticism is still tingling consider this, blood flow restriction training has been around at least since 1966 when Yoshiaki Sato first developed a “blood flow moderation exercise” method which later became the Kaatsu Training society. Now that the mechanisms of BFR are well measured and understood we can begin to implement this tool effectively into a training program. I’m happy to say that there’s nothing here that needs to be taken on insufficient evidence… this time.


1. Zachary Pope, et. al., “Exercise and Blood Flow Restriction,” Journal of Strength and Conditioning Research, 27(10), 2013.

2. Moore, Daniel R., Kirsten A. Burgomaster, Lee M. Schofield, Martin J. Gibala, Digby G. Sale, and Stuart M. Phillips. “Neuromuscular Adaptations in Human Muscle Following Low Intensity Resistance Training with Vascular Occlusion.” European Journal of Applied Physiology 92, no. 4–5 (August 2004): 399–406.

3. Takarada, Y., Y. Nakamura, S. Aruga, T. Onda, S. Miyazaki, and N. Ishii. “Rapid Increase in Plasma Growth Hormone after Low-Intensity Resistance Exercise with Vascular Occlusion.” Journal of Applied Physiology (Bethesda, Md.: 1985) 88, no. 1 (January 2000): 61–65.

4. Abe, Takashi, Satoshi Fujita, Toshiaki Nakajima, Mikako Sakamaki, Hayao Ozaki, Riki Ogasawara, Masato Sugaya, et al. “Effects of Low-Intensity Cycle Training with Restricted Leg Blood Flow on Thigh Muscle Volume and VO2MAX in Young Men.” Journal of Sports Science & Medicine 9, no. 3 (September 1, 2010): 452–58.

5. P Renzi, Christopher, Hirofumi Tanaka, and Jun Sugawara. “Effects of Leg Blood Flow Restriction during Walking on Cardiovascular Function.” Medicine and Science in Sports and Exercise 42 (November 1, 2009): 726–32.

6. Bunevicius, Kestutis, Arturas Sujeta, Kristina Poderiene, Birute Zachariene, Viktoras Silinskas, Rimantas Minkevicius, and Jonas Poderys. “Cardiovascular Response to Bouts of Exercise with Blood Flow Restriction.” Journal of Physical Therapy Science 28, no. 12 (December 2016): 3288–92. https://doi.org/10.1589/jpts.28.3288