How to Do Blood Flow Restriction Training (BFR)

Blood Flow Restriction (BFR) Training is a Japanese muscle-building technique that occasionally makes its way into the mainstream. Peter Attia recommends it. NBA and NFL players use it. And you’ll see top bodybuilders and powerlifters swearing by it, too. I’ve been doing it on and off for over a decade, and it’s helped me add over two inches to my arms.

Restricting blood flow sounds strange and dangerous, but it helps you stimulate muscle growth with much lighter weights, making it one of the safer ways to stimulate muscle growth. It also seems to be quite good for our blood vessels. In fact, outside of athletes and bodybuilders, it’s most commonly used in rehab and with older lifters.

The research is promising, too, with the latest meta-analysis showing it can help with muscle and strength gains, at least under some circumstances.

Blood Flow Restriction Training, also known as BFR training, occlusion training, and KAATSU training, is when you restrict blood flow out of your limbs while training them. You can do this with a cuff, bandage, or tourniquet. Blood still flows into your muscles, but once it’s there, most of it gets trapped, creating fearsome muscle pumps.

It isn’t as weird as it sounds. When you lift weights, you naturally restrict blood flow. This is especially true of high-rep training. It pumps your muscles full of metabolites and other anabolic hormones, encouraging muscle growth. Blood Flow Restriction Training exaggerates this effect, ostensibly stimulating even more muscle growth.

Blood Flow Restriction Training feels like a fad. Right from the very beginning, my intuition was screaming at me, urging me not to be fooled by it. But my intuition was wrong. There’s now been over a decade of rigorous research proving its effectiveness. It’s great for building muscle (meta-analysis, study, study, study).

For example, in a study by Bjornsen and colleagues, the competitive powerlifters following a strength training program increased their quad size by 0.5% in 7 weeks. Those who added BFR to their workouts increased their quad size by 7.7% (study). Mind you, this study was done on powerlifters, who are notorious for only doing low-rep sets. If your workout program already includes high-rep training, I wouldn’t expect such extreme benefits.

We also need to consider the opportunity cost. Energy spent on BFR is energy that could have been spent doing something else. That’s where the benefits begin to falter. Doing a few sets of BFR biceps curls is great for building muscle, but it isn’t always better than doing a few regular sets of biceps curls.