What is BFR?

Blood Flow Restriction or BFR has become an increasingly recognized form of strength training. So what is it? Although BFR has really increased in popularity in the past several years, it has actually been around since the 1960s where it began in Japan. BFR is the application of a device (typically a type of band) that is placed on a person’s limb(s) that restricts a percentage of arterial blood flow to a specific area of the body AND occludes venous blood flow return from that same area back to the heart. Then while the band is restricting blood flow, the person performs a series of low load exercises for about 10-20 minutes. This produces a low oxygen (hypoxic) environment which in turn causes increased muscle activation, muscle fatigue, and anabolic (muscle growth) signals.

In other words, let’s say we are using BFR to strengthen someone’s leg, the BFR band on that leg blocks blood flow to the muscles below the band and also stops some of the blood from being pumped back up to the heart. In a way think of it as a fancy tourniquet. Then the person may complete a series of knee extensions, lunges, squats, calf raises, etc with the number of reps specified by the Physical Therapist. During the exercises, the muscles are fatiguing quickly due to decreased amount of oxygen being delivered to the area. This leads to activating more muscle fibers to help perform the exercise…leading to more fatigue…leading to signals that are sent to the body to promote muscle growth.

What are the benefits?

  • Increased muscle strength
  • Increased muscle hypertrophy 
  • Increased aerobic capacity 
  • Improved cardiovascular function
  • Reduced muscle atrophy
  • Improved bone density
  • Enhanced rehabilitation
  • Enhanced performance

Sounds interesting but why do this over traditional strength training with heavy loads?

Big reasons why BFR may be used include times when lifting high loads are either contraindicated due to injury/surgery or intolerable due to pain. Sometimes when a person has an injury and/or surgery, they are unable to weight train at heavy loads in order to allow whatever injury/surgery they have to properly heal. Also, for the people who may have arthritis in their joints, heavy weights might be too painful to lift to get the best results. As you can see both of these categories of people could potentially greatly benefit from BFR where they can get similar strength gains without having to stress the joints to the same degree as traditional strengthening. Another way BFR has been used especially for performance-based athletes is to use BFR in conjunction with traditional strengthening. This allows the muscles to be stimulated through different avenues and improve strength leading to increases in performance. However, one thing I want to point out is BFR should not be a replacement for traditional strength training. Strength gains occur through 3 main pathways: neural, mechanical, and metabolic. BFR is great for metabolic gains as it produces the metabolic signals for muscle growth but HIGH load training is needed for neural and mechanical strength gains to occur.

Is it safe?

Maybe you’re thinking…sounds kind of scary, weird, and possibly unsafe. Just like anything in life, there are some risks involved, even driving to the grocery store has a risk if you think about it. However, the risks of BFR are extremely low and really depend on your medical history. That being said, we recommend always being evaluated by a medical professional (Physical Therapist, Physician, etc.) to see if BFR is for you. 

-Arron Pierce PT, DPT