22 Mar

Blood Flow Restriction (BFR): The ultimate shortcut to building muscle?

Blood Flow Restriction (BFR) is a technique that uses a medical grade tourniquet around the upper arm or upper leg to restrict blood flow while exercising. I know, this sounds highly unusual! Research has shown that by restricting the blood flow in and blocking the blood flow out of the limb, there is a significant increase in strength and muscle size that can be achieved. This is all done while using very light weights that would normally not stimulate growth in the body. This type of training has gained popularity in both the rehab setting as well as professional sports based on its safety and effectiveness. In this blog we will explore what BFR is, how it works, and how it can help you reach your goals.

What is Blood Flow Restriction?

Traditionally for muscle strength and size to occur, lifting weights greater than 70% of our 1-repetition max is required over a 12–16-week period. Individuals who are experiencing pain or following a surgery, athletes during a season, or individuals who are deconditioned due to inactivity may not be candidates for this high load training.

Blood flow restriction on the leg while performing a leg press

Example of BFR on the leg during a leg press

Blood Flow Restriction relies on a specially designed tourniquet (or cuff) that is wrapped around the upper arm or the upper leg and is pressurized which restricts blood in and out of the limb. This creates a hypoxic environment (low oxygen) for the working muscles which causes a cascade of signals to the brain leading to a significant boost in growth factors and repair substances into the body. This low oxygen environment enables the individual to build size and strength using very light weight with results equal to or better than a high intensity program (and over less time!). Research shows that with a consistent frequency of 2-3 times per week, increased size and strength of target muscles can be seen over a 6-8 week period of time.

How does BFR work?

At IPA Physio, we utilize the Personal Tourniquet System for BFR from a company called Delfi, which is the gold standard for quality and safety when it comes to Blood Flow Restriction. This unit, which is the most advanced Blood Flow Restriction machine available, utilizes a built-in doppler which enhances the safety of the patient. The doppler automatically and accurately senses the lowest pressure required to restrict the blood flow to the limb for that specific patient based on a multitude of factors including their body mass, blood pressure, hydration levels, etc. Once the minimum pressure is identified, we then take a percentage of that pressure for the patient to exercise with based on the body part. The reduced blood flow to the working muscles causes less oxygen to reach the muscles.

Blood flow restriction on the arm while performing a bicep curl

Example of BFR on the arm during a bicep curl

This creates an “anaerobic” working environment which recruits “fast twitch” muscles, while using a weight that has been determined to be “light to easy”. Lactic acid and other metabolites are released from the working muscles (this is the burn sensation you feel when exercising) due to the low oxygen environment and are trapped in the limb by the cuff. The lactic acid and metabolite accumulation (the burn!) signals the brain to release LOTS of growth factors (such as growth hormone, CRITICAL for collagen synthesis which is the process of growing new connective tissue) in anticipation of muscle damage. The growth hormone also initiates the process of muscle repair and growth through a chain of events, activating muscle stem cells and insulin like growth factors (IGF).

However, since the weight is too light to cause damage to the muscles, the muscle doesn’t break down as it would during traditional high intensity weight lifting. The result is a SIGNIFICANT increase in muscle size and strength, a significant boost in muscle protein synthesis, rapid repair of tendons, bone and ligaments, and less damage to our joints.


Who benefits from BFR?

Blood Flow Restriction training will benefit a wide range of individuals from post-surgical, geriatric, weekend warriors, to professional athletes. People who are recovering from an injury or recovering from surgery will find they can build strength and repair injuries using light weight without aggravating their injury. They will also find that they can protect their muscles from becoming weaker if they have loading or weight bearing restrictions based on their surgeons’ guidelines. BFR is just as effective for people who are not experiencing pain as well! Individuals who just want to get stronger or professional athletes who need to maintain or build strength without overtraining will notice huge gains in their performance and progress while using BFR.

Benefits of BFR at IPA Physio

BFR has been shown to have several benefits, including:

  1. Faster recovery: BFR has been shown to accelerate muscle growth and repair, leading to faster recovery after an injury or surgery.
  2. Reduced muscle atrophy: BFR has been shown to reduce muscle atrophy, which is the loss of muscle mass that can occur after an injury or surgery.
  3. Improved strength: BFR has been shown to improve strength and muscle size, which can be particularly beneficial for people who have undergone surgery or suffered an injury that limits their mobility or activity levels.
  4. Improved tissue health: BFR has been shown to improve the health and durability of tendons and connective tissue, which is beneficial for people who have experienced an injury or following surgery.


Blood Flow Restriction is a highly effective technique that has gained popularity in recent years, particularly in rehab settings and professional athletics. By restricting blood flow to the muscles during exercise, BFR creates a hypoxic environment that stimulates muscle growth and improved muscle function. BFR has been shown to have several benefits in rehab and sports performance, including faster recovery, reduced muscle atrophy, improved strength, reduced pain, and improved tissue health. If you are considering BFR as part of your rehab or training, be sure to work with a qualified healthcare professional who can guide you through the process and ensure your safety.

About the Author

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Ian McVay

Ian McVay graduated PTA school in 2015 with Honors, and has since treated a variety of patient populations in Colorado, California, and Oregon. Working as a Director of Rehab for multiple facilities in Colorado, Ian developed his skill with outpatient, neurologic, dementia, post op and subacute populations. While working hand in hand with therapists and spinal surgeons in San Diego, Ian worked with his patients to exhaust all avenues of conservative care prior to surgery or other invasive options such as injections. Ian served in the US Navy submarine force as a torpedoman for 5 years where he developed the drive for excellence which is seen in each treatment and patient interaction. Ian began working at IPA Physio Portland in 2021, and dove headfirst into the world of Functional Manual Therapy® (FMT). Ian successfully passed with the first group of PTAs testing for CAFMT, achieving a cumulative score of 95.875% (Distinction). He has additional certifications used extensively at IPA Physio Portland including Certified Laser Therapist, Myofascial Decompression Certified, Certified Kinesio Taping Practitioner, Credentialed Clinical Instructor, and Certified Assistant in Functional Manual Therapy.