During the COVID-19 era, many gyms across the world are closed. Like many of you, I was unable to use my regular gym and found myself scrambling for some sense of normalcy in my fitness routine. Over the last ~10 years I've barely missed any workouts—I normally train 5-6 times per week, combining both strength training and aerobic work. Considering I only had a few dumbbells, I was worried that the strength I had worked to build for such a long time would quickly diminish. With that desperation, I had to get creative.
I began experimenting and researching ways that I could get a great workout at home without spending thousands of dollars on overpriced gym equipment. During my research, I stumbled over a term that I had heard before but never really tried for myself: "blood flow restriction training." While this term sounds dangerous and nerve-racking to some, I was intrigued by the concept. I already understood the physiological mechanisms behind it, but now I was curious to see what the data showed in the literature.
During my search, I was surprised to find a significant amount of evidence in support of blood flow restriction training. Dozens of studies confirmed its efficacy for muscular growth (hypertrophy), healing injuries, improvements in aerobic capacity, and strength development. This article will summarize some of the impressive studies I've come across on the subject, and you'll find the citations to the full papers at the end if you'd like to do some more digging on your own.
Muscular Hypertrophy and Strength
For populations over 50-years of age, building and preserving muscle mass is incredibly valuable. Between the ages of 50-60, muscle mass decreases by 1-2% annually, and after the age of 60 that number jumps to 3%. With strength training, this decline can be attenuated. Several studies have shown that blood flow restriction training can be beneficial for elderly and deconditioned individuals.
A meta-analysis of 11 different papers analyzed the effects of low load blood flow restriction training compared with high load training and low load training/walking. The results resoundingly showed that blood flow restriction training was effective for this population.
Compared to high-level resistance training, blood flow restriction training elicited a similar increase in muscle mass. Why is this significant? If you take an individual who is 65 and you can produce similar changes in hypertrophy with lower loads, you are minimizing their risk of injury. In a population that is especially susceptible to injury, it is advantageous to have them train with lighter weights. Without blood flow restriction, an athlete might need to squat 155 pounds or more to build muscle mass, but with blood flow restriction training they could see gains with an empty barbell. As trainers we are constantly seeking ways to keep our clients injury-free and this is a perfect solution for those who desire to build muscle safely and effectively.
Adding blood flow restriction bands for a walk can facilitate muscle growth. In the studies reviewed, light to moderate walking with the occlusion bands on yielded similar effects to low load resistance training (~13% increase). A ~25 minute walk per day (three times per week) elicited a favorable change in muscle mass. For most people, walking without blood flow restriction training would not be nearly enough of a stimulus to yield hypertrophic effects. This finding is beneficial for individuals who may not be interested in strength training but still wish to create favorable changes in body composition (3).
Strength gains in this population were statistically significant as well. Compared with low-intensity training without occlusion of blood flow, the blood flow restriction training group saw larger increases in strength. When compared with the high-load group, however, strength gains were lower. Scientists speculate that this could be due to neural recruitment requirements for each type of training (6).
When it comes to younger athletic populations, the results are similar. A study performed on college students were randomly allocated into three groups: low-intensity resistance training, low-intensity resistance training combined with moderate blood flow restriction, and high-intensity resistance exercise. They tested 1-rep maximum knee extensions and quadriceps size. After 8 weeks of training, the researchers found that low intensity resistance training with blood flow restriction yielded similar gains in both parameters to high-intensity exercise. The low-intensity training group that did not use blood flow restriction saw the least amount of progress. Again, the key takeaway here is that the participants were able to gain just as much strength and muscle mass as the high-intensity group but with far lighter loads.
So now we know that blood flow restriction training can have a positive influence on muscle strength and size, but can it also enhance your VO2 Max or aerobic conditioning? The currently available research seems to show favorable affects.
An 8-week cycling training program in young men sought to compare differences in VO2 Max, muscle volume, and time to exhaustion with and without blood flow restriction bands. Across all three measurements, the blood flow restriction group saw massive improvements when compared with the control group (7).
Similarly, another study on male soccer players tested differences in VO2 Max and rate of perceived exertion (RPE) during 400-meter sprints. The players performed 3-4 sets of sprints per session with adequate rest between sets. While the rate of perceived exertion was significantly higher in the occlusion training group, so too was the impact on their VO2 Max (1). This tactic is especially helpful for sport coaches who are looking to improve the conditioning of their athletes throughout the competitive season.
Blood flow restriction training creates a hypoxic climate in the body, which increases metabolic stress. This method can ultimately yield superior aerobic performance by recruiting a greater number of fast-twitch muscle fibers.
Musculoskeletal injuries are overwhelmingly common amongst active populations. Competitive athletes who are injured may miss out on weeks or months of valuable gameplay due to an injury. With this in mind, coaches are often desperate to seek out different modalities to promote faster recovery among their players. Blood flow restriction is one such method that can help expedite this process.
Since lighter loads are used with occlusion training, an injured athlete is able to prevent post surgical atrophy and resume training much quicker than they otherwise could. Several studies have been done to test whether blood flow restriction training was safe after various musculoskeletal surgeries.
A meta-analysis of twenty different studies on patients with ACL tears, knee osteoarthritis, and several other musculoskeletal injuries reviewed the current body of literature on the topic. When an athlete is returning to training with an acute or chronic injury, the typical protocol coaches use is either low load or bodyweight training. While this keeps the patients safe from harm, the athlete may become frustrated, feeling like they are not progressing in the way that they would like. An athlete who is used to high-intensity, high-volume training may quickly tire of doing light goblet squats with ease. Instead, he can opt to do those same goblet squats with blood flow restriction bands and get a much larger training effect. The analysis found that "compared with low-load training, low-load BFR training is more effective, tolerable and therefore a potential clinical rehabilitation tool." If you are a postoperative athlete or you train postoperative athletes, this is an excellent tool in your toolbox to give them the most bang for their buck (4).
In fact, even several years after an ACL surgery, patients have seen improvements in muscle strength and symmetry using occlusion training. Once the area is fully healed, athletes may still notice differences in muscle size for years post surgery. Muscular imbalances can be tricky to remedy, but blood flow restriction is an excellent answer. A study from 2019 found that quadriceps size increased significantly in the affected leg after performing a simple 4-week long at-home exercise protocol. Thus, blood flow restriction training is beneficial both in the acute stage of injury or surgery and in the long term many years post-operation (5).
When the bands or cuffs are removed after your workout, a ton of blood flow will inevitably rush to the area. As a result of the excess blood flow to the area, this may help speed up the healing process. While limited studies on this concept exist today, this is my personal hypothesis. I believe there are many health markers that can be improved with this type of training that have yet to be explored in detail.
How to Implement Blood Flow Restriction Training
Now that I've showed you just how effective this method is, you may be wondering how you can implement it! Fortunately, it's both safe and easy to utilize in your training.
First, you need to buy some occlusion bands. The most expensive units are medical grade and cost $400+, but you can buy bands for as cheap as $35 (which is how much I paid for mine) and get the same exact effect. You can also use knee wraps or Voodoo floss if you own either of those.
Once you buy the bands, you want to make sure you put them on properly. You will place the bands either at the crease of your hips or right in your armpit area depending on whether you're training your arms or your legs. It's not advised to put the bands in the crease of your knee or elbow. Most guidelines recommend that the bands should be at about 70-80% tension. Imagine that 100% would be completely cutting off circulation to a limb while 10% means the bands are sliding off of your limbs. The happy medium is that 70% range, where it feels tight and your veins are popping out a bit, but there's no tingling in your fingers or toes.
When most people think about limiting blood flow, they automatically assume that it's extremely dangerous. Fortunately much of the research today shows that this method is safe for the majority of people. Unless you have an issue with blood clotting or diabetes, you can likely use these bands without any health risks (13). Of course, ask your doctor beforehand just to be sure!
When you finish your first workout with the blood flow restriction bands you'll notice that a.) the burn you'll feel on a given exercise is insane and b.) you will have the best muscle pump of your life!
With all of this in mind, I highly recommend trying it out for yourself! This is a great method that you can implement cheaply and effectively into your fitness program to achieve a wide array of goals. Whether you're looking to build your aerobic conditioning, increase strength, or just rehabilitate an injury, blood flow restriction training could be a great choice for you!
Abe, T., Fujita, S., Nakajima, T., Sakamaki, M., Ozaki, H., Ogasawara, R., ... & Sato, Y. (2010). 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(3), 452.
Centner, C., Wiegel, P., Gollhofer, A., & König, D. (2019). Effects of blood flow restriction training on muscular strength and hypertrophy in older individuals: a systematic review and meta-analysis. Sports Medicine, 49(1), 95-108.
Cook, C. J., Kilduff, L. P., & Beaven, C. M. (2014). Improving strength and power in trained athletes with 3 weeks of occlusion training. International journal of sports physiology and performance, 9(1), 166-172.
Erickson, L. N., Lucas, K. C. H., Davis, K. A., Jacobs, C. A., Thompson, K. L., Hardy, P. A., ... & Noehren, B. W. (2019). Effect of blood flow restriction training on quadriceps muscle strength, morphology, physiology, and knee biomechanics before and after anterior cruciate ligament reconstruction: protocol for a randomized clinical trial. Physical Therapy, 99(8), 1010-1019.
Hughes, L., Paton, B., Rosenblatt, B., Gissane, C., & Patterson, S. D. (2017). Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis.British Journal of Sports Medicine,51(13), 1003-1011.
Kilgas, M. A., Lytle, L. L., Drum, S. N., & Elmer, S. J. (2019). Exercise with blood flow restriction to improve quadriceps function long after ACL reconstruction. International journal of sports medicine, 40(10), 650-656.
Laurentino, G. C., Ugrinowitsch, C., Roschel, H., Aoki, M. S., Soares, A. G., Neves Jr, M., ... & Tricoli, V. (2012). Strength training with blood flow restriction diminishes myostatin gene expression. Med Sci Sports Exerc, 44(3), 406-12.
Lixandrão, M. E., Ugrinowitsch, C., Laurentino, G., Libardi, C. A., Aihara, A. Y., Cardoso, F. N., ... & Roschel, H. (2015). Effects of exercise intensity and occlusion pressure after 12 weeks of resistance training with blood-flow restriction. European journal of applied physiology, 115(12), 2471-2480.
Meyer, R. A. (2006). Does blood flow restriction enhance hypertrophic signaling in skeletal muscle?. Journal of applied physiology, 100(5), 1443-1444.
Minniti, M. C., Statkevich, A. P., Kelly, R. L., Rigsby, V. P., Exline, M. M., Rhon, D. I., & Clewley, D. (2020). The safety of blood flow restriction training as a therapeutic intervention for patients with musculoskeletal disorders: a systematic review. The American journal of sports medicine, 48(7), 1773-1785.
Sata, S. (2005). Kaatsu training for patella tendinitis patient.International Journal of KAATSU Training Research,1(1), 29-32.
Telfer, S., Calhoun, J., Bigham, J., Mand, S., Gellert, J., Hagen, M., ... & Gee, A. (2020). Biomechanical Effects of Blood Flow Restriction Training after ACL Reconstruction. Medicine and Science in Sports and Exercise.
Loenneke, J. P., Wilson, J. M., Wilson, G. J., Pujol, T. J., & Bemben, M. G. (2011). Potential safety issues with blood flow restriction training. Scandinavian journal of medicine & science in sports, 21(4), 510-518.