Blood flow restriction training: Benefits, rehab uses, and safety guide

Maryke Louw
6 days ago
9 min read

Learn how blood flow restriction (BFR) training works, its benefits for athletes and injury rehab, and how to use it safely. This evidence-based guide explains the science, optimal cuff pressures, and how to reduce risks so you can build strength and muscle with lighter loads.

Remember, if you need help with an injury, you're welcome to consult one of our physios online via video call.

A person using blood flow restriction while training his arms and the words: Blood flow restriction - rehab benefits and safety

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In this article:

What is blood flow restriction training?
Does it work for training in athletes?
Does blood flow restriction training work as injury treatment?
Putting blood flow restriction training into practice
Blood flow restriction training safety and side effects
How we can help

What is blood flow restriction training?

Blood flow restriction (BFR) training involves wrapping a cuff or tourniquet around the top of a limb – so, between the heart and the muscle(s) you want to target during exercise – to inhibit blood flow.

This causes blood to pool in the working muscle, so the muscle quickly runs low on oxygen and waste products from exercise build up. In this low-oxygen state, the muscle tires much faster than usual, and this signals to your body to make the muscle stronger, even though the exercise itself is quite light.

In short, BFR tricks the body into reacting as if you were lifting heavy weights – making it a useful strategy to build strength and muscle with lighter loads.

Does it work for training in athletes?

👍 Evidence from recent research indicates that BFR training is effective for uninjured athletes.

In a systematic review of available research that compared the effect of normal training combined with BFR training versus just normal training:

7 out of 9 studies found that adding BFR led to significantly greater strength gains compared to normal training, and
about half of the studies also reported increases in muscle size.
Improvements in certain sport-specific performance measures (such as sprint speed or jump height) were observed in 3 of 4 studies that tested them.

A similar analysis that crunched the numbers from 28 studies involving 542 athletes found that BFR training can produce small to large improvements in multiple fitness areas – including strength, power, speed, and muscular endurance. In that analysis, strength measures improved the most, but even explosive power and sprint speed saw moderate improvements.

BFR training also tended to improve body composition by increasing muscle mass (and possibly reducing fat) – though it did not significantly change overall body weight in the short term.

A woman doing a weighted back squat. — Because regular weight training also strengthens your ligaments, tendons, bones, and cartilage, athletes tend to mix things up by combining various training methods.

What is notable is that these benefits are achieved with much lighter weights than traditional training, which might allow you to train your muscles “hard” while reducing recovery time for your joints.

👉 But it’s important to understand that your joint cartilage and ligaments don’t benefit much from BFR training, so general weight training without BFR is still necessary if you want to strengthen these types of tissue.

💡 In practice, many athletes use BFR as a supplementary training tool – for example, doing low-load BFR sessions in addition to normal high-load workouts to maximize gains.

Does blood flow restriction training work as injury treatment?

BFR training has attracted a lot of interest in injury rehabilitation, because it might be particularly useful when working the injured tissues hard (using heavy weights) during rehab exercises might be painful or unsafe.

Below we look at the research on whether BFR can help with muscle and tendon injuries.

Muscle injuries

After muscle injuries or surgeries, muscle atrophy (wasting) and weakness are common problems. BFR training has been used in these situations to help rebuild muscle without over-stressing the injured area.

For example, following knee surgeries like ACL reconstruction, patients often lose significant thigh muscle mass. Studies have explored adding BFR to post-ACL surgery rehab exercises to combat this muscle loss. The results have been mixed but somewhat promising.

A recent review of six research papers that focus on using BFR in ACL reconstruction rehab found a variety of outcomes – from almost no added benefit to a significant benefit.

The straight-leg-lift exercise — Blood flow restriction training can potentially turn low-load exercises (like the straight leg lift) used for muscle activation into muscle-building exercises.

In the studies with the beneficial results, BFR allowed these post-surgery patients to perform gentle exercises (like straight leg raises or low-load knee extensions) and still get a strength benefit similar to heavier training in some cases. This can be invaluable early in rehab when the graft and joint are still healing and heavy lifting isn’t safe.

💡 Overall, while more research is needed, BFR might turn out to be a useful tool to speed up muscle recovery and return of strength after an injury, especially when traditional high-load training cannot be used.

Tendon injuries

Rehabilitating tendon injuries (like Achilles tendinopathy or tendon ruptures) usually involves loading the tendon to encourage it to form more collagen cells, which is the main building block of tendons.

Traditionally, this is done with relatively heavy-load exercises, which not everyone can tolerate. The thinking around BFR training is that it might be an alternative or adjunct for tendon rehab, since it can provide a training effect on the muscle-tendon unit with lower loads.

A 2024 review of studies on the effect of BFR training on both healthy and injured tendons found inconsistent results about the effect on the tendon itself. In other words, it’s still unclear whether BFR directly makes a healing tendon stronger or thicker any faster than normal rehab does.

However, the same review noted that several studies reported that adding BFR led to decreased pain, increased strength (muscle strength, i.e. they could lift more weights), and improved functional performance in patients with tendinopathy or after tendon repair. For example, in cases of Achilles and patellar tendinopathy, patients doing BFR could perform low-load leg exercises that resulted in pain relief and functional improvements over a few weeks.

A person with a blood flow restriction cuff around their upper thigh. — The benefits of BFR for muscles seem well supported, but the evidence so far shows little to no benefit for tendon health or strength.

🤷‍♀️ At first glance, these results appear positive, but I wonder whether BFR could cause trouble in the longer term if used in this way for tendon rehab.

Are you actually putting the injured tendon at increased risk if you increase the muscle strength at a significantly faster rate than the tendon strength? Could this lead to a scenario where, for instance, you ramp your Achilles loading activities and sport up too quickly because your muscles are strong and your pain has dropped significantly, and then you reinjure the tendon because it could not keep up?

👉 For this reason, I would wait for clearer evidence of positive effects on tendon health and strength before I start recommending BFR therapy to my patients who are recovering from tendon injuries.

Putting blood flow restriction training into practice

How to do BFR training and how often? The optimal training parameters are still being studied, but some patterns have emerged. Let’s look at what got the best results in BFR training studies.

What type of cuff to use

It is important to get the cuff tightness right (see further down) – too loose will be ineffective and too tight might be unsafe.

So get yourself a set of cuffs with a pressure gauge. Here are some examples available on Amazon – all have cuffs for the arms and the legs.

The unit of pressure used is mmHg. It stands for “millimetres of mercury” and comes from old-fashioned pressure gauges – 1 mmHg equals the pressure needed to push a column of mercury 1 millimetre high.

How much pressure to apply

👍 The safest way to get the correct pressure for your limb size and cuff type is to find your limb occlusion pressure (LOP) – the minimum pressure to completely block to the blood flow to and from the limb – and then to apply a percentage of that pressure.

To find your LOP and optimal training pressure for a specific limb:

inflate the cuff gradually while keeping the limb still
keep an eye on the pressure gauge
you will feel your pulse starting to throb in the limb, and then it will disappear
the pressure reading when your pulse disappears is your LOP
now deflate the cuff to the desired pressure
in research studies, the best results for arms have been achieved between 40% and 50% of LOP, and for legs it was between 60% and 80% of LOP – legs need more pressure because the arteries are larger.

Some sanity checks for the correct pressure range:

Correct tightness: You feel a firm squeeze and your muscles “pump up” quickly, with a strong burning sensation during exercise. Skin may turn slightly red or pink.
Too tight: Tingling, numbness, sharp pain, or skin turning pale/blue. 🚨 Deflate immediately.
Too loose: Minimal sensation, muscles don’t fatigue quickly, no “pumped” feeling in the muscle.

How long should a BFR training session be?

Research studies where the muscle was kept under restriction for about 10 minutes at a time (for example, doing 4 sets of an exercise with short rest intervals while the cuff stays inflated) yielded the best results.

How often?

A 2024 analysis of BFR research noted that training programmes with a frequency of at least 3 BFR sessions per week tended to produce better improvements in athletes. But this will depend on your fitness level, ability to recover, and what other training you're doing.

How many weeks?

The same analysis found that programmes that lasted at least 6 weeks tended to yield better results.

Blood flow restriction training safety and side effects

Is BFR training safe? When done properly in appropriate individuals, BFR is generally considered safe.

A systematic review of BFR’s effects on various body systems found no serious detrimental effects on the cardiovascular, endocrine, or muscular systems. In fact, most of the reviewed studies reported either positive or neutral effects on things like blood pressure, nerve function, and hormone levels when BFR is used correctly.

That said, like any exercise technique, BFR isn’t completely risk-free. There have been rare cases of serious side effects reported in the literature. For example, one rehab study on Achilles tendon rupture patients recorded two instances of re-rupture and one case of deep vein thrombosis (blood clot) in the BFR group.

🚨 To stay on the safe side, it is recommended that certain high-risk individuals avoid BFR training or only do it under medical supervision – for example, people with uncontrolled high blood pressure, vascular disorders, a history of deep vein thrombosis, or sickle cell disease.

More commonly, people might experience mild side effects such as discomfort or pain in the limb during BFR (the muscle burn can be quite intense), temporary numbness or tingling, superficial bruising or petechiae under the cuff, or slight dizziness if the cuffs are released too abruptly.

👉 The bottom line: BFR should feel challenging (muscles will burn and limbs will feel tight), but it should not cause sharp pain, numbness, or discoloration – if it does, release the cuff.

How we can help

Need help with an injury? You’re welcome to consult one of the team at SIP online via video call for an assessment of your injury and a tailored treatment plan.

We're all UK Chartered Physiotherapists with Master’s Degrees related to Sports & Exercise Medicine or at least 10 years' experience in the field. But at Sports Injury Physio we don't just value qualifications; all of us also have a wealth of experience working with athletes across a broad variety of sports, ranging from recreationally active people to professional athletes. You can meet the team here.

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About the Author

Maryke Louw is a chartered physiotherapist with more than 20 years' experience and a Master’s Degree in Sports Injury Management. Follow her on LinkedIn and ResearchGate.

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Blood flow restriction training: Benefits, rehab uses, and safety guide

What is blood flow restriction training?

Does it work for training in athletes?