Traditionally, it’s been taught that in order to build muscle and strength, you need to lift relatively heavy.
Recently though, a new style of training called blood flow restriction training has been making waves due to some research showing individuals can build muscle using incredibly light weights (relative to the one-rep max). In fact, studies have shown that an individual can stimulate hypertrophy using loads as low as 20-30% of 1-RM!
How can this be and should you try blood flow restriction training?
We’ll answer those questions and more, but first, let’s briefly review what blood flow restriction training is.
What is Blood Flow Restriction Training?
Blood flow restriction (BFR) training is one of the newest training methods being used in both performance and rehabilitation applications. You may have also seen it referred to as occlusion training or KAATSU training.
BFR training essentially entails performing resistance training while wearing special wraps that limit (restrict) blood flow to the working muscle.
Now, it should be noted that when used properly, the wraps do not cut off circulation to your muscles (that would be dangerous), they simply slow down the rate of return of blood from the muscle to the heart.
As a result, blood stays in your muscles longer, which impacts muscle physiology in several interesting ways.
How Does BFR Work?
As you know, the heart is responsible for pumping blood to all the various tissues of the body, including your muscles. Carried within the blood are oxygen, glucose, amino acids, hormones, and other nutrients needed to maintain function and perform optimally in the gym.
Now, if you remember back to basic biology class, blood is shuttled to your muscles through arteries and it returns to the heart via a different set of blood vessels known as veins.
When you lift weights (particularly lighter weights for higher reps), the rate of blood flow going into the muscle exceeds that of blood leaving the muscle. This leads to an accumulation of metabolic waste products in the muscle as well as forces muscles cells to swell and expand with nutrients and fluid, which contributes to “the pump” that you get.
Interestingly, both of these mechanisms also serve to stimulate hypertrophy.
Blood flow restriction training seeks to mimic the effects of high rep, lighter weight pump training by restricting venous blood flow, thereby increasing the amount of blood and metabolites that accumulate in the muscle initiating a cascade of metabolic activity that stimulate protein synthesis and muscle growth.
Specifically, studies show that BFR training increases mTOR signaling (mTOR is the pathway that drives protein synthesis) and reduces levels of myostatin (a protein that stunts muscle building).[1,2] Coupled with the cellular swelling induced by the BFR bands, you’ve created an environment extremely conducive to muscle growth.
How to Perform BFR?
BFR is typically performed in the research setting using pressure cuffs or a KAATSU device, but for the everyday lifter who doesn’t have access to that expensive equipment, knee wraps or BFR bands will do the trick.
Simply tighten the wraps or bands around the top of the muscle you’re planning to train to where it is roughly a 7 out of 10 tightness for legs and about an 8-9 tightness for arms. The reason you do not want to overly tighten the bands is that it could cut off blood flow to the muscle, leading to tingling and pain.
When wrapping the arms, the BFR band should be placed up higher on the arm and tucked into your armpit. When wrapping the legs, the bands should be on the upper thigh close to the crotch.
Benefits of BFR Bands
The primary benefit of BFR bands is that they allow you to use lighter weights in your workouts while still building muscle, which helps lower the amount of stress and strain placed on your joints, ligaments, and tendons. Subsequently, this allows you to perform more training volume with less risk of injury or overtraining.
Additionally, blood flow restriction training can help minimize loss of muscle mass and reduce bony healing time during the early immobilization phases following injury. This is important to help maintain and improve muscle size and strength without having to worry about lifting heavy weights during rehabilitation processes, thereby providing an excellent work around while you recover.
BFR bands can also be helpful for building muscle when you happen to be traveling and only have access to a poorly equipped gym (e.g. most hotel gyms that only have dumbbells up to 50 pounds).
Blood flow restriction training is also great to use during a deload week or those times when you’re not really feeling at your best to perform a heavy resistance-training workout to help maintain muscle size and strength while also incurring less muscle damage and fatigue.
And if you’re a beginner, studies demonstrate that training with BFR bands may be beneficial for building strength more than just heavy lifting on its own.
Lastly, BFR bands are also great for getting massive pumps during your workouts and they can be effective for both those looking to build muscle and lose fat!
Final Notes on BFR Training
BFR bands allow you to build muscle and strength without having to lift heavy weights all the time, which makes it an ideal option for those during a deload week or those rehabbing an injury. However, while research shows that BFR training is effective for building muscle, that doesn’t mean people should stop training with heavy weights either. Lifting heavy in and of itself offers benefits that BFR training can’t, such as improving bone density.
Therefore, if you’re looking to implement BFR training in your program, we suggest using it either during your deload weeks when you’re taking a break from the heavy weights and lower reps, when you’re trying to working around some minor issues like tendonitis, or after you’re heavy compound exercises are completed for the day and you’re looking to get in some extra volume and pump work.
- Fry CS, Glynn EL, Drummond MJ, et al. Blood flow restriction exercise stimulates mTORC1 signaling and muscle protein synthesis in older men. J Appl Physiol (1985). 2010;108(5):1199–1209. doi:10.1152/japplphysiol.01266.2009
- Laurentino, G. C., Ugrinowitsch, C., Roschel, H., Aoki, M. S., Soares, A. G., Neves, M. J., Tricoli, V. (2012). Strength training with blood flow restriction diminishes myostatin gene expression. Medicine and Science in Sports and Exercise, 44(3), 406–412. https://doi.org/10.1249/MSS.0b013e318233b4bc
- Kubo, K., Komuro, T., Ishiguro, N., Tsunoda, N., Sato, Y., Ishii, N., Fukunaga, T. (2006). Effects of low-load resistance training with vascular occlusion on the mechanical properties of muscle and tendon. Journal of Applied Biomechanics, 22(2), 112–119.
- Luebbers, P. E., Fry, A. C., Kriley, L. M., & Butler, M. S. (2014). The effects of a 7-week practical blood flow restriction program on well-trained collegiate athletes. Journal of Strength and Conditioning Research, 28(8), 2270–2280. https://doi.org/10.1519/JSC.0000000000000385
- Gentil P, Oliveira E, Bottaro M. Time under tension and blood lactate response during four different resistance training methods. J Physiol Anthropol. 2006;25(5):339-344.