Blood Flow Restriction Training

What is Blood Flow Restriction Training (BFR)?

The current American College of Sports Medicine guidelines recommend that individuals perform resistance training at a load of >65% 1 repetition maximum (1RM) to achieve strength and hypertrophy gains. ¹
Traditionally heavy resistance training is used to improve strength and cause hypertrophy (muscle growth).
When you are injured or in a healing period e.g. post surgery or if you have a fracture, you need to reduce your load. During this period people often lose strength and muscle mass as they cannot lift or maintain their usual load.
Blood Flow Restriction (BFR) Training can allow people to gain strength and hypertrophy similar to high load training while utilising very low loads (20-30% 1 RM).
For example if you could usually lift 100kg for 1 repetition you could see the benefit of BFRT when lifting just 20-30kgs!

What does it involve?

This method involves placing an inflatable cuff around the upper arm (for upper body) or the upper thigh (for lower body) and applying pressure to restrict the amount of blood flow that can move into and out of a muscle whilst exercising.
The settings are controlled by your physio on the machine or via an app on their phone depending on the blood flow restriction unit used

How does it work?

There are different types of muscle fibres in the body; Type I (slow twitch) and type II (fast twitch)
Research shows that the growth capacity of fast-twitch fibres is approximately 50% greater than that of slow-twitch fibres ²
The reduction in blood flow causes an increase in the recruitment of type 2 muscle fibres at lower intensities and causes a build-up of metabolic by-products which signals to your body to increase muscle strength and size.
It works by causing a metabolic stress (which the body needs to build muscle mass and strength) which has a number of effects – increases lactate, increased iEMG activation, downregulates myostatin, increases recruitment of satellite cells, increases muscle protein synthesis. ³

What are the benefits?

Faster results – Improvement in hypertrophy can sometimes be seen as quickly as after 2 weeks of use compared with the typical 8-12 weeks of hypertrophy training ⁴
Studies show BFRT increases long-term muscle protein turnover, ribosomal biogenesis, and muscle strength to a similar degree as High Load Resistance Exercise.³
There is evidence it can provide pain relief ^{5, 6}
Growth of new blood vessels (Angiogenesis) ⁷
Very little soreness post treatment compared with normal hypertrophy training

When would it be used?

BFRT can be used for pre-operative rehab when you may be injured/in pain and not able to lift heavy weights/tolerate a high load but want to maintain and build hypertrophy, and decrease muscle endurance post op. ⁸
It can be used after surgery to prevent muscle atrophy (loss)
It can be used after surgery in conjunction with NMES or electrical stimulation prevent muscle atrophy and increase activation
It can be used later in end stage rehab before you return to play to improve endurance and Aerobic capacity
It can be used for pain management for example it can be used on a painful achilles tendon to provide pain relief and allow us to load the tendon
To maintain muscle mass while you are injured such as with a stress fracture

Is it safe?

BFTR has been shown to be very safe and studies have shown that training with BFR is just as safe as strength training. ^{4, 9}

Your physio will first screen you to make sure BFR training is appropriate for you and can be used safely. Your physiotherapist will explain the technique in detail, and will discuss any questions you have before your first session.

Like all interventions there are some side effects but most of these are rare, your physiotherapist will ensure that it is carried out safely and that all side effects have been discussed prior to using BFTR.

Who is it suitable for?

There are some medical conditions that need to be considered before taking part in BFR training.

There are some reasons that precautions may be needed or that BFR may not be able to be done such as;

High blood pressure 150/95mm/Hg or above
Pregnancy or less than 3 months postpartum
Blood clotting disorders or medication that increases your risk of blood clots/bleeding
History of pulmonary embolism (PE) or deep vein thrombosis (DVT)
Cardiac/heart disease – history of heart attack or atrial fibrillation
Previous stroke or TIA (Transient Ischaemic Attack)
Active infection or acute inflammation of the treatment area
Systemic inflammatory disorders eg. rheumatoid arthritis

There are other conditions that precautions need to be taken with but these will be discussed in full with you by your physiotherapist.

What do I do after?

After the session we advise you to maintain your normal activity levels but rest from unaccustomed activity for 24 hours.
As you will be fatigued immediately after we do not recommend you do anything too strenuous or heavy as you will be tired so it may increase risk of injury.
If you have any concerns before, during or after your treatment session, please discuss with your physiotherapist.

Sources:

Owens Recovery Science

https://www.owensrecoveryscience.com/?gclid=Cj0KCQiA95aRBhCsARIsAC2xvfzKqyH2PepHBR6WaWGDXO5hw9tW-WLHz_rJme4lBreEUC0qOqd5QeMaAqFlEALw_wcB

References:

American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009 Mar;41(3):687-708. doi: 10.1249/MSS.0b013e3181915670. PMID: 19204579.
Adams GR, Bamman MM. Characterization and regulation of mechanical loading induced compensatory muscle hypertrophy. Compr Physiol 2: 2829–2870, 2012.
Sieljacks P, Wang J, Groennebaek T, Rindom E, Jakobsgaard JE, Herskind J, Gravholt A, Møller AB, Musci RV, de Paoli FV, Hamilton KL, Miller BF, Vissing K. Six Weeks of Low-Load Blood Flow Restricted and High-Load Resistance Exercise Training Produce Similar Increases in Cumulative Myofibrillar Protein Synthesis and Ribosomal Biogenesis in Healthy Males. Front Physiol. 2019 May 29;10:649. doi: 10.3389/fphys.2019.00649. PMID: 31191347; PMCID: PMC6548815
Maughan, R., J.S. Watson, and J. Weir, Strength and cross‐sectional area of human skeletal muscle. The Journal of physiology, 1983. 338(1): p. 37-49
Ellingson, L.D., et al., Does exercise induce hypoalgesia through conditioned pain modulation? Psychophysiology, 2014. 51(3): p. 267-276.
Hughes, L. and S.D. Patterson, The effect of blood flow restriction exercise on exercise-induced hypoalgesia and endogenous opioid and endocannabinoid mechanisms of pain modulation. Journal of Applied Physiology, 2020. 128(4): p. 914-924
Hunt, J.E., et al., Time course of regional vascular adaptations to low load resistance training with blood flow restriction. Journal of applied physiology, 2013. 115(3): p. 403-411
Grapar Žargi, T., Drobnič, M., Stražar, K., & Kacin, A. (2018). Short– Term Preconditioning with Blood Flow Restricted Exercise Preserves Quadriceps Muscle Endurance in Patients after ACL Reconstruction. Frontiers in Physiology, 9, 1150
Brandner, C.R., et al., Reported side-effects and safety considerations for the use of blood flow restriction during exercise in practice and research. Techniques in Orthopaedics, 2018. 33(2): p. 114-121.