Blood Flow Restriction Training
What is Blood Flow Restriction Training?
BFR has become a popular tool for rehab because it simulates higher stress on the body while maintaining the training resistance at a low load. During blood flow restriction training, an adjustable cuff is placed close to a pathological area of the limb, and the cuff pressure is increased until there is a significant degree of venous occlusion. The patient undergoing BFR is then instructed to perform one or a series of exercises under that sustained pressure.
How does a “tourniquet” simulate higher load resistance training?
While training at a higher load, blood vessels residing within and in between muscles become compressed as the muscles forcefully contract. As this occurs, there is a decrease in oxygen delivery and increase in waste products such as lactate. An increase in lactate also sends a signal to your body that it needs to release growth hormone, a hormone that is responsible for muscle recovery through collagen synthesis (collagen formation). Basically, BFR creates and sustains this environment, forcing the body to work harder under this metabolic stress and ultimately leading to muscle hypertrophy (bigger and stronger muscles).
Why do physical therapists select this modality for some of their patients?
- More gains, less pain.
- Creating a program suitable for patients that are limited in their strengthening abilities due to an acute injury or post surgical pain have the ability to improve their muscle mass or at least prevent muscle atrophy (muscle wasting).
- Improvements in blood flow.
- Decreased oxygen levels from higher levels of BFR can contribute to positive blood vessel adaptations such as angiogenesis (formation of new blood vessels).
- Effects on bone loss.
- Research has shown there is a small effect on bone loss prevention post surgically; however, more research is needed in this.
What do we know about potential rehab benefits for patients with Achilles tendon pathology?
BFR training research has shown similar results when comparing the integrity of tendons after BFR vs high-intensity resistance training. A 14 week long research study in 2019 that compared Achilles tendon stiffness and cross sectional area of 36 healthy participants without any underlying pathology, showed that low-load BFR yielded statistically significant comparable results to high load training. Both training groups showed increased Achilles tendon stiffness and cross sectional area. These effects were attributed to the low oxygen environment created by the BFR which has also been shown to stimulate production of tendon stem cells and fibroblast growth factor, that basically team up and enhance the repair of this tendon. This study shows promising evidence for patients with a pathology of the Achilles tendon; however, further research is needed to confirm the results of BFR on patients with an achilles tendinopathy or patients with an achilles tendon repair, as timeline, frequency, intensity, and specific exercise prescription are important to create parameters for a physical therapy intervention.
Evidence Based Research
- Apta.org. 2022. Perspective | Blood Flow Restriction, Beyond Just Muscle. [online] Available at: <https://www.apta.org/article/2021/07/16/blood-flow-restriction-beyond-just-muscle> [Accessed 12 January 2022].
- Centner, C., Lauber, B., Seynnes, O., Jerger, S., Sohnius, T., Gollhofer, A. and König, D., 2019. Low-load blood flow restriction training induces similar morphological and mechanical Achilles tendon adaptations compared with high-load resistance training. Journal of Applied Physiology, 127(6), pp.1660-1667.
- Physiopedia. 2022. Blood Flow Restriction Training. [online] Available at: <https://www.physio-pedia.com/Blood_Flow_Restriction_Training> [Accessed 12 January 2022].
–Dr. Amalia Porcel PT, DPT