Some exercise trends are hard to ignore, and very few have impacted the therapy and sports medicine communities like blood flow restriction training – but what exactly is it, and why does it matter?

What Is Blood Flow Restriction Training?

The term blood flow restriction training (BFR) involves the use of a cuff or band to stop blood flow out of a limb while also limiting blood flow into the limb. This method is then paired with a specific exercise routine (sometimes called occlusion training). This reduced blood flow with exercise causes a number of benefits in the limb that’s being trained. (1)

Blood flow restriction training is used in multiple settings, including physical therapy and other fitness settings:

• In physical therapy, BFR is used to enhance the recovery of injuries that limit the amount of exercise or weight that can be tolerated.

• In the fitness world, BFR can be used to increase muscle mass and strength in addition to a regular resistance training program.

While BFR can be used for different purposes, research continues to refine a training protocol that seems to work across the board for both physical therapy and fitness.

In the past, BFR has been done using blood flow restriction bands to limit blood flow while exercising. Unfortunately, elastic bands and belts don’t provide specific or reliable pressure to achieve the best results.

Modern BFR is done using a pressurized blood flow restriction cuff which detects blood pressure and adjusts in real-time to maintain steady occlusion pressure and limit blood flow appropriately.

How Does BFR Work?

The goal of BFR training is very straightforward: reduce blood flow to make exercise harder, since your muscles require blood flow to function.

But what makes blood flow restriction therapy so fascinating is the effects it has on the body, which is why so many patients are seeing it in their recent care plans.

During BFR training, unique stress is placed on the area being exercised that stimulates a number of hormonal effects.

One major effect is that specialized muscle cell signals stimulate increased protein building, which promotes muscle hypertrophy – an increase in muscle size. At the same time, myostatin, a protein that limits muscle growth, seems to be reduced after blood flow restriction training. (2)

One of the most interesting effects of BFR training is the high activation of type II muscle (or fast twitch) fibers with very low resistance. Under normal circumstances, type II muscle fibers are only used to such a degree during higher intensity work.

This increased stimulation of type II muscle fibers leads to increased muscle hypertrophy (more muscle growth), which has a number of benefits for just about everyone, young or old.

Even more interesting, research shows that these effects are seen not just in the area below the blood pressure cuff, but in the entire limb. That means that if you practice BFR with a cuff just above your knee and exercise your calf muscle, you’re also getting the same benefits for your thigh and hip.

What Conditions Can Benefit From BFR?

Blood flow restriction training can be used for a variety of reasons, but it’s especially helpful in treating conditions like soft tissue injuries, fractures, and deconditioning.

The term soft tissue describes parts of your body like muscles, tendons, and ligaments. When you experience an injury to one of these structures, it can limit your ability to participate in rehab exercise, in turn limiting your potential for recovery.

Using BFR as a means to exercise allows you to stimulate muscle growth and soft tissue recovery without putting a ton of load on your injury site. 

Fractures are difficult injuries that can completely halt your ability to exercise. If you experience a fracture, the traditional first line of treatment would be to avoid exercise and other forms of loading or pressure on the area.

However, blood flow restriction training creates a unique workaround that allows for the benefits of exercise without directly stressing the injured area.

For example: if you are healing from an ankle fracture that stops you from putting weight on your ankle or performing strengthening exercises, your therapist can use BFR to stimulate strengthening and healing throughout your entire leg. 

Deconditioning refers to the weakening of soft tissues and a reduced tolerance for exercise. Many people experience deconditioning after a long bout of bedrest or chronically living a sedentary lifestyle.

If you are significantly deconditioned while starting your exercise program, you may not have enough endurance to get the benefits from exercise before fatigue sets in. By adding BFR to their training program, deconditioned patients can gain more from exercise without needing significant weight or complicated workouts. 

Contraindications and Precautions

Although blood flow restriction training is generally very safe, research is still being done to map out specific safety protocols for various situations. For this reason, it’s important to know the current dos and don’ts of safe and effective exercise with BFR.

Blood flow restriction training can be used by adults who:

• Are recovering from a soft tissue injury, fracture, or surgery

• Are attempting to recover from significant deconditioning

• Seek to increase muscle strength and size

 Blood flow restriction training should not be used by adults:

• With a history of deep vein thrombosis (DVT) or blood clotting disorder

• With a heart condition, history of blood clots or poor circulation in their limbs

• With cancer, active infection, or kidney problems

• Who are pregnant (3)

As with other forms of exercise, make sure to consult with your primary care doctor before starting a new exercise program.

Results in Older Adults

Many of the benefits of blood flow restriction training, including increased muscle strength and size, can be seen by older adults which can have a large effect on their everyday life. (4)

For an older adult, everyday activities like getting up from bed or crossing the street can be seriously impacted by lack of muscle strength. In addition to traditional strength training, blood flow restriction training can be used to improve performance in daily life – but strength isn’t just important during everyday activities.

Fall prevention and recovery both require a considerable amount of strength. This means that BFR training can have an important role in preventing falls and maintaining safety for older adults.

Strength is important for daily activities and safety, but should also be trained regularly to help you participate in your favorite hobbies.

As you age, activities like throwing a ball or dancing can become harder with each passing year. Luckily, regular exercise can help you to maintain and improve the strength you need to keep up with your grandkids and your favorite activities.

Blood flow restriction training is a great addition to a strength training program because it allows you to continue working on your strength when other factors, such as an injury or illness, are limiting you.

Summary

Although blood flow restriction training is still being studied and refined for a number of conditions, the benefits are becoming very clear for adults of all ages. Adding BFR to your rehabilitation or fitness routine may give you the edge to improve your strength, safety, and quality of life.

References

1. Patterson SD, Hughes L, Warmington S, Burr J, Scott BR, Owens J, Abe T, Nielsen JL, Libardi CA, Laurentino G, Neto GR, Brandner C, Martin-Hernandez J, Loenneke J. Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety. Front Physiol. 2019 May 15;10:533. doi: 10.3389/fphys.2019.00533. Erratum in: Front Physiol. 2019 Oct 22;10:1332. PMID: 31156448; PMCID: PMC6530612. https://doi.org/10.3389%2Ffphys.2019.00533

2. Cognetti DJ, Sheean AJ, Owens JG. Blood Flow Restriction Therapy and Its Use for Rehabilitation and Return to Sport: Physiology, Application, and Guidelines for Implementation. Arthrosc Sports Med Rehabil. 2022 Jan 28;4(1):e71-e76. doi: 10.1016/j.asmr.2021.09.025. PMID: 35141538; PMCID: PMC8811521. https://doi.org/10.1016%2Fj.asmr.2021.09.025

1. Lorenz DS, Bailey L, Wilk KE, Mangine RE, Head P, Grindstaff TL, Morrison S. Blood Flow Restriction Training. J Athl Train. 2021 Sep 1;56(9):937-944. doi: 10.4085/418-20. PMID: 34530434; PMCID: PMC8448465. https://doi.org/10.4085%2F418-20

1. Centner, C., Wiegel, P., Gollhofer, A. et al. Effects of Blood Flow Restriction Training on Muscular Strength and Hypertrophy in Older Individuals: A Systematic Review and Meta-Analysis. Sports Med 49, 95–108 (2019). https://doi.org/10.1007/s40279-018-0994-1