Blood Flow Restriction Training (BFR)

Blood Flow Restriction (BFR) training is a fairly new technique that has been gaining attention in the rehabilitation world. BFR involves restricting the blood flow to a muscle while performing exercises. This restriction occurs through the use of cuffs or bands placed around limbs (upper and lower body) during low-intensity workouts. When the cuffs are applied, the blood has difficulty leaving the working muscles, resulting in increased blood accumulation, or "pooling," within those muscles. BFR has the ability to stimulate muscle growth and improve strength with minimal load, and this has made it a powerful tool in rehabilitations, especially with tendonopathies. 

The Science Behind Blood Flow Restriction Training

Hypoxic and Metabolic Stress

When blood flow is restricted, the muscles become hypoxic (low oxygen). This lack of oxygen, combined with the buildup of metabolic byproducts like lactate, creates a state of metabolic stress in the muscle. This metabolic stress is one of the primary triggers for muscle hypertrophy and strength adaptations.

Recruitment of Fast-Twitch Muscle Fibers

Under normal conditions, muscle fibers are recruited in a manner based on the load that is being applied. Low-intensity exercise recruits slow-twitch muscle fibers first, while higher intensities recruit fast-twitch fibers. However, during BFR, the restriction of blood flow causes fatigue to set in much faster. As a result, even light weights stimulate the fast-twitch muscle fibers (which are responsible for explosive and powerful movements). These fibers have a greater potential for hypertrophy, which leads to muscle growth with lighter loads.

 Increased Growth Hormone Release

BFR training has been shown to increase the secretion of growth hormone (GH) in response to metabolic stress. Growth hormone is a key player in muscle recovery and growth, and its elevation following BFR exercises helps to further promote tissue repair and muscle development. 

 Venous Pooling and Muscle Swelling

As blood is restricted from leaving the muscle, blood vessels expand, and there is an increase in the volume of blood within the muscle. This swelling effect creates a sense of tightness in the muscle, which, in turn, stimulates mechanoreceptors that play a role in muscle adaptation. This swelling is not only a sign of the muscle’s response to BFR but also contributes to the mechanical tension necessary for muscle growth.

Why is Blood Flow Restriction Training Effective?

BFR training is effective because it induces the muscle-building effects of high-intensity training without the need for heavy weights, reducing the mechanical load on joints and connective tissues. This makes it particularly useful for:

• Injury Rehabilitation: Athletes recovering from injuries or surgery can use BFR to maintain or increase muscle mass while avoiding the strain of heavy lifting.

  • Research shows it works really well with tendon injuries. 

• Strength and Hypertrophy Gains: For seasoned athletes, BFR can be an excellent addition to a training regimen for continued muscle growth and strength improvements, especially when regular training reaches a plateau.

  
  

What does a treatment session look like if I am going to be doing BFR training?

If you are a candidate for blood flow restriction training, a typical treatment session could look like: Cuff is applied to the appropriate limb (arm or  leg), an occlusion rate typically between 40-80% would be selected. Three exercises would be performed going through a specific protocol. Exercise one would be completed doing 30 reps, 30 sec rest, 15 reps, 30 sec rest, 15 reps, 30 sec rest, 15 reps, 1 minute rest. Repeat for the remaining two exercises. For best results, complete multiple times a week is beneficial. 

In Summary

Blood Flow Restriction training is a valuable tool that can help with recovery, rehabilitation and muscle growth utilizing low intensity loads. The science behind BFR training is rooted in metabolic stress, muscle fiber recruitment, venous pooling and growth hormone secretion, which together help stimulate hypertrophy even with lighter weights. Whether for injury recovery or strength training, BFR provides a valuable tool for many different goals. If you have any injury that could benefit from BFR, reach out to your physical therapist or come see us here at Precision!

Hope this helps!

Dr. Noelle O’Hara, DPT

1. Burton I. Blood Flow Restriction Training for Tendinopathy Rehabilitation: A Potential Alternative to Traditional Heavy-Load Resistance Training. Rheumato. 2023; 3(1):23-50. https://doi.org/10.3390/rheumato3010003

2. https://simplifaster.com/articles/blood-flow-restriction-rehab-athletes/