By: Dr. Jesse Espe, PT, DPT, CSCS, CIDN
So… What Is BFR exactly?
In order to fully understand what blood flow restriction (BFR) training is and how it works, first we need to brush up on how the cardiovascular system works. In a nutshell, your arteries carry oxygenated blood to your working muscles, then your veins carry the deoxygenated blood back to your heart. BFR was originally developed in the 1960’s in Japan, known as KAATSU training there, to play with this system and try to hack your physiology. Essentially it involves applying a band or cuff proximally to the muscle(s) being trained, typically upper arms and legs. The cuff is then inflated to a determined pressure. This pressure then will limit the amount of venous return out of the muscle while still allowing the arteries to carry oxygenated blood to the working muscles. Once applied, the athlete will complete a low load (20-30% of 1 RM), with high repetitions (15-30) with a short rest interval between sets (30 seconds).
That’s great, but I want gainz!
Let’s first dive into some physiology of muscle hypertrophy. Hypertrophy (aka gainz) is an increase in the diameter and protein content within a muscle fiber. An increase in the cross-sectional area of the muscle fiber directly correlates to an increase in strength.1 We know that we need an increase of mechanical tension and metabolic stress to get these results. These have been theorized to create an increase of cell swelling, hypoxia, increased fast-twitch muscle recruitment, and release of hormones.2 The combination of these will cause a cascade of events that lead to muscle hypertrophy (gainz). Traditionally we can create the muscle strain and metabolic stress through lifting heavy loads (70% of 1 RM). The problem arises when we are unable to lift at 70% or greater of our 1 RM. This can be due to a myriad of reasons, mostly notably injury.
BFR for Recovery
Traditionally when injured we are told to rest, take it easy for a while, or ramp back up slowly. If you were under the care of a healthcare professional, you are typically “cleared” well before you are back to being able to train at your normal 70% 1RM. So, the problem is, how do we get stronger to get back to doing the things we want to do and train the way we want, if we can’t do the things proven to make us stronger? BFR is the answer! BFR has been shown to have similar strength gains as traditional heavy lifting, but with only using 20-30% of 1RM.2 This means we are able to resume training, building strength in weakened parts of our body, with a decreased risk of reinjuring tissue with heavy loads. Whether coming back from a surgery, strain, sprain, or pulled muscle, BFR can help get you back in the game sooner. Traditionally it takes 6-12 weeks of a strength training program to see hypertrophy, BFR has shown these gains in 2-4 weeks.
What if I don’t have an injury? BFR for Training
Trying to get that first pullup, muscle up, pistol squat? Trying to bench press/squat/dead lift your body weight/1.5X bodyweight/2x bodyweight? Crushing your WODs but still have hit a plateau? Having trouble getting stronger at a certain movement or muscle group can be challenging. Most don’t have enough extra time to dedicate to the training, a BFR session takes 20 minutes. Others can’t achieve the volume needed to reach their goal due to increased muscle soreness. BFR cuts down on the amount of delayed onset muscle soreness (DOMS) because you are using a light load.
I’m not a meathead looking for gainz, I’m an endurance athlete, so I’m out right?
Not so fast. Studies have shown that low-to-moderate exercise training with BFR to have significantly greater increase in aerobic capacity than the same training without BFR.3 In these studies the training with BFR is a low heart rate, steady state, 20 minute exercise session on the cardio equipment you are looking to improve on. For runners this is typically a walk on a treadmill, but the same protocol applies for any endurance event. This means that you could continue with your current training protocol, add a 20 min BFR session 2-3 times a week, and see significant improvements without adding considerable amounts of time or strain on your body.
BFR has been shown to be a safe and effective way to come back from injury and increase strength and endurance performance. If you have any questions or are interested in learning more about BFR, contact us at firstname.lastname@example.org
Dr. Jesse Espe, PT, DPT, CSCS, CIDN
1. Bonnieu A, Carnac G, Vernus B. Myostatin in the pathophysiology of skeletal muscle. Current genomics. 2007 Nov 1;8(7):415-22.
2. Hughes L, Paton B, Rosenblatt B, Gissane C, Patterson SD. Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis. Br J Sports Med. 2017;51(13):1003-1011.
3. Formiga MF, Fay R, Hutchinson S, et al. Effect of aerobic exercise training with and without blood flow restriction on aerobic capacity in healthy young adults: a systematic review with meta-analysis. Intl J Sports Phys Ther. 2020;15(2):175-187.