Blood Flow Restriction and Me: What is BFRT and How Can it Help?

Blood flow restriction training is a rehabilitation tool that when used correctly, can have a huge influence on maintaining muscle size and strength following an injury or a prolonged period of inactivity.

Blood flow restriction training (BFRT) is a training and rehabilitation strategy, involving the use of pressured cuffs to maintain a partial inflow of blood to the muscle, whilst preventing the blood flowing out. 

The cuffs, which sit on your upper arms or legs, do this by adding pressure to the muscle, which allows blood to flow into the muscles and limits the amount going out so as to keep more blood in the selected muscles during your training session.

In this blog we will explore why this technique may be helpful, and the wide-ranging benefits it can have. 

Humans have x3 muscle types: slow twitch (Type 1), fast twitch (Type 2a), and faster twitch (Type 2x). They serve many purposes within their roles. Below I break down the x3 muscle types in relation to Blood Flow Restriction Training:

  • Type 1 – Slow twitch fibres use oxygen to function. They are used for slower movements with low force or speed requirements and do not produce lactate (a by-product produced by the body during intense activity).
  • Type 2a – Fast twitch fibres work in the absence of oxygen. They are used for higher force or speed movements and do produce lactate. 
  • Type 2x – This muscle type does everything that Type 2a (above) does but faster and with more force. 

Note: It is much easier to increase muscle size by training the type 2 muscle fibres.

When we are injured, the muscles in and around the injury are unable to contract as hard as they would previously; a subconscious response from the nervous system to protect the injured region. This means that we can either produce no force or movement at the injured site, or only low force movements (for which it is only necessary to use the Type 1 – slow twitch muscle type). 

Where muscles and muscle fibres are not being used, they begin to decrease in size (atrophy) very quickly. If we cannot access the big and powerful Type 2 muscle fibres regularly, there will be noticeable change in the muscle size in a short amount of time.

In an ideal world, we would be able to use the big and powerful Type 2 muscle fibres as soon as possible post injury, to minimise unnecessary muscle loss, build muscle around the injury, and therefore achieve better outcomes.

This is where BRFT comes in. 

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Benefits of BFRT #

When exercising using BRFT, the blood and oxygen can get into the muscle, but cannot get out. The oxygen that gets in is quickly used by your Type 1 muscle fibres, but when it runs out, they cannot function, and the type 2 muscle fibres are forced to come to the party.

This can be achieved at loads as low as 20 – 30% of 1 rep max, which is what sets this type of training apart from any other (for example, if you could normally squat 100kgs, you would see the benefits of BFRT when only squatting 20 – 30kgs). Essentially, you can access the high force, large growth, powerful muscle fibres without using a heavy weight or moving too fast. It can also be implemented during bed rest, so you are getting some stimulus to the muscles when you are laying down – if used soon after your injury.

When you are ready to return to exercise it can then be used during low level aerobic training, ahead of starting your resistance training programme. 

So now we have accessed the Type 2 muscle fibres, we can access a whole world of benefits.

As mentioned above, the use of Type 2 muscle fibres produce lactate and metabolites, which have the following effects:

  • Fluid is shifted from the muscle cell wall, causing the cell to expand. This stimulates a protein complex, which in turn stimulates muscle growth (muscle protein synthesis). In short, you get a big muscle pump’, which leads to muscle growth (if nutritional demands are met).
  • Increased satellite cell activity. Without going into too much detail, satellite cells respond to muscle damage, to repair or replace the damaged muscle. BFRT causes very little damage, but still has an effect on satellite cell activity, therefore eliciting repair and growth without any damage. 
  • Lactate leads directly to an increase in growth hormone. This stimulates IGF1, which is a hormone that together with growth hormone reproduces, regulates and regenerates cells and aids in collagen production. Collagen is the ultrastructure of all tissues, so can help with repairing muscles, tendons and cartilage. 
  • This rise in the growth hormone increases the expression of mRNA, which is the first of a series of stages that assembles new tissue for the tendon. BFRT can therefore also be helpful with tendon injuries, in order to increase the area of the tendon. It is worth noting at this point that a tendon also needs to be stiff to perform well, which is not BRFT’s strong point — we will come back to this later. 
  • Causes an up regulation of VEGF, a signalling protein, which is a part of a series of reactions that forms new blood vessels to help improve the healing of bones.

Another topical consideration would be that of the quarantine we recently experienced. With gyms closed and access to heavy weights limited, the ability to maintain muscle size from lighter loads would have been very attractive to many – it certainly helped me! The results of less activity or changes in training during lockdown are becoming apparent to us, and BRFT is an effective way to get back to your previous fitness levels.

Further Benefits (excluding Lactate Production) #

Due to the load being much less than conventional resistance training, BFRT offers the added benefits of:

  • little to no tissue stress
  • decreased joint stress
  • short recovery time
  • very little soreness post session

It can also have a surprising pain-relieving effect, which I have felt first-hand following a knee injury. This does not mean that it will magically fix an injury. However, it may allow you to move more freely for 24 – 48 hours afterwards, allowing you complete your daily tasks and routine. Finally, BFRT can increase the work your heart needs to do during aerobic exercise without increasing muscular effort. This is because the blood vessels are restricted, the heart needs to work harder to get the blood around the body. You can therefore get a bigger aerobic stimulus from low intensity aerobic training than you would normally. 

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What BFRT is Not #

BFRT is not a magical cure to everything, but it is a very helpful tool in your exercise toolbox. It cannot replace very heavy resistance training for strength, but it can keep the muscle size, so when you are ready to train with heavy weights once again, the muscle has the potential to get stronger. It is a similar story for power training, as it doesn’t lend itself well to sprinting or jumping. Personally, I use it the most with people who cannot perform to their usual level because of injury, or to preserve muscle mass, as this is what my job in rehab requires.

Safety #

BFRT has been shown to be very safe, and a lot of the research is based around using it with the elderly to improve bone and muscle health. There is a list of conditions that need to be considered before taking part in BFRT training however; so a medical history should always be taken before beginning BFR training. The pressures also needed to be calculated based on a percentage of an individual’s limb occlusion pressure therefore appropriate cuffs need to be used with a pressure gauge, and ideally a doppler for accuracy. Limb occlusion pressure is how much pressure the cuff exerts on the limb during this type of training, and is calculated before the training begins by a trained professional. 

New and Novel Ideas for BFRT #

For those who already have an interest in BFRT, there is a lot of new research and ideas coming out surrounding this technique. Questions such as the below have been asked:

  • Could it be used as a shortened warm up or potentiation tool, due to its ability to stimulate Type 2 muscle fibres?
  • Could it be used for recovery because of its healing benefits? Or could it be used as a replacement for ice after an acute injury, by limiting blood flow into the injured tissue? 

I think it is only a matter of time before BFRT becomes a commonly used training tool. If you are injured or immobile BFRT would certainly be beneficial in aiding your recovery. 

Alternatively, if you’re injury free and aiming for a fitness goal, for example focusing on upper body strength with press ups, you could get a lot more bang for your buck if you had some cuffs. 

If BFRT is of interest to you please feel free to get in touch with me at andrew.​[email protected]​puresportsmed.​com. I would be happy to advise on the purchasing of cuffs and Coaching to ensure you to get the most out of them.