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Does BFR (Blood Flow Restriction Training) / occlusion training really work?

Funktioniert BFR (Blood Flow Restriction Training) / Okklusionstraining wirklich?

Blood flow restriction training (BFR training for short), also known as occlusion training, has been causing a stir in the world of strength training and bodybuilding for some time now.

It sounds new, it sounds scientific and some describe it as revolutionary.

At first glance, it sounds like just another marketing ploy like many others, designed to sell magazines, equipment, pills and powders.

And if you're skeptical, that's fine - you should be.

The more time you spend educating yourself about muscle building, the clearer something will become: If something sounds too good to be true - if it sounds too easy, too effective and too innovative - it usually is.

But what about BFR training? What is it, how is it supposed to work and how effective is it? Is it perhaps even dangerous? And how do you do it correctly?

This article will give you answers to these questions and more. By the end of the article, you should have enough knowledge to decide whether BFR training is right for you and be able to use this training technique safely and effectively.

What is Blood Flow Restriction Training?

Blood Flow Restriction Training involves restricting the venous blood flow of a muscle group while it is being trained. This training technique is also known as occlusion training or KAATSU training.

The first thing you need to know about BFR training is that the goal is not to completely cut off the blood supply to the trained muscle. Rather, the goal is to slow the rate at which blood from that muscle returns to the heart.

This results in the blood remaining in the exercised muscle longer than normal, which - as you will see in a moment - affects muscle physiology in several ways.

How does Blood Flow Restriction Training work?

Blood is the body's delivery system for oxygen, nutrients, glucose, hormones, and other compounds that you need to stay alive, move weights, run, jump, and so on. For this reason, your muscles need a continuous supply of blood. Your heart pumps blood to your muscles via arteries - large veins whose walls themselves contain muscles. Blood is returned to your heart via veins, which are a different type of vein that runs through your entire body.

When you do resistance training - especially in a higher repetition range - the amount of blood that is pumped from your heart to your muscles exceeds the amount of blood that is transported from your muscles back to your heart. This is one of the reasons why you feel a pump when you train with weights.

The pump decreases when you rest between sets, as the arterial blood flow to the muscles decreases and the blood slowly flows back to the heart from the overcrowded muscles.

The aim of a BFR workout is to prolong this pump. This is achieved by tying a band around the exercising arm or leg during the workout, which allows blood to continue to flow to the muscle but restricts the return flow of blood.

The pump is great, of course, but how can it affect muscle growth? Read on to find out.

Can blood flow restriction training increase muscle growth?

The short answer is yes and there are several ways through which this happens. Let's look at these one by one.

When you exercise, your muscle cells burn energy at a much higher rate than they do at rest. As they do this, metabolic products of this process accumulate faster than the body can remove or break them down and some of these molecules act as anabolic signals, telling your body to increase muscle mass and strength.

From a technical perspective, this process is also known as metabolic stress, which is one of the three primary mechanical pathways to stimulate muscle growth (progressive overload and muscle damage are the other two).

Because BFR training reduces the rate at which these waste products are removed from the muscles, it allows them to remain in the muscle longer and have a greater anabolic effect on the muscle cells. In other words, this enhances the muscle-building effect of metabolic stress.

Resistance training also causes the muscle cells to fill with fluid and nutrients and enlarge. This cellular swelling acts as a further signal to stimulate muscle growth (1).

Occlusion training enhances the muscle-building effect of this effect by prolonging the time your muscle cells remain swollen (1). Scientific research shows that restricting blood flow can enhance the effects of certain genetic pathways involved in muscle growth.

As you can see, your body uses a complex network of chemical messengers to signal your cells to grow or shrink.

One of these growth signals is a protein known as mammalian Target of Rapamycin (mTOR for short) and one of the signals that inhibits muscle growth is the protein myostatin. Studies have shown that BFT training increases mTOR levels while decreasing myostatin levels, creating an environment in the body that is conducive to muscle growth (2, 3).

Restricting blood flow can also stimulate muscle cells to release their own anabolic hormones via a process known as autocrine signaling (4) - and by keeping blood in the muscles for longer, these hormones have more time to interact with muscle cells.

Another way in which BFT training can help you build muscle faster has to do with what happens when you stress your muscles to the point of muscle failure, where you simply can't perform any more repetitions.

You may have heard that muscles only grow in response to the last reps of a set - the hard reps that make your muscles burn. While that's not entirely true, it's not completely wrong either.

One of the easiest ways to ensure continuous overload, damage and exhaustion of your muscles is to regularly stress them to the point of muscle failure - or close to the point of muscle failure (you finish the set one or two reps before reaching muscle failure).

When you do this, you activate a greater amount of muscle tissue than with lighter sets and this has positive effects on muscle development (5). This is why loading your muscles regularly to the point of muscle failure - or close to the point of muscle failure - is an important aspect of building muscle and strength.

In a normal set, you only reach this point at the very end of your set, after you have already performed several repetitions.

So if you want to increase the frequency with which your muscles reach muscle failure, you need to do more sets and many more repetitions. That's all well and good, but you can only do a certain amount of work per muscle group per week before you exceed your body's recovery capacity and overtraining symptoms occur. This is especially true if your training consists primarily of heavy multi-joint exercises.

BFR training is helpful in this regard because while it does not increase muscle activation levels more than normal training, it allows you to achieve a higher overall level of muscle activation during a training session with less muscle damage than normal training (6).

It is similar to rest-pause training in that it tricks your muscles into 'believing' you are using much heavier weights than is actually the case (7).

To summarize, these are the benefits of BFR training:

  • Using lighter weights puts less stress on your ligaments, tendons and joints, allowing you to complete more volume with less risk of injury and overtraining (8). This can also be helpful if you are dealing with an injury or nagging pain. A BFR workout allows you to train more efficiently with lighter weights that (hopefully) won't aggravate your existing problems. Being able to achieve a useful muscle building stimulus with lighter weights can also be useful if you are training in a poorly equipped gym.
  • Assuming you are relatively new to training with weights, scientific research shows that BFR sets in combination with heavy traditional sets can increase strength better than heavy sets alone (8).
  • If you are de-loading or taking an extended time off from training, then you can use BFR training to maintain your level of development with far less muscle damage and fatigue.
  • If, for whatever reason, you don't feel ready for a heavy training session, then you can use BFR Training to complete a less strenuous training session.

As you can see, there are numerous reasons to use this unusual training method.

The biggest question, however, is safety.

Is Blood Flow Restriction Training dangerous?

At first glance, restricting the supply of blood to the muscles during exercise sounds like a bad idea - something that could have a long list of unwanted side effects.

Surprisingly, however, scientific research shows that there is no evidence that BFR training could be dangerous (10). This makes sense when you realize that this technique only reduces blood flow out of the muscles and does not inhibit the flow of blood to the muscles, which would be dangerous.

This means that you need to make sure that the bands/straps are not too tight, but as you will see in a moment, this is not difficult to achieve. If they are so tight that they can cause problems, then they will be very uncomfortable and you will lose feeling in the relevant limbs, which you will definitely notice.

And even if you're one of those 'no pain, no gain' types who ignores any discomfort, scientific research suggests that even if the blood supply is completely cut off, it would take around two hours before nerve and muscle damage occurs (11). So you would have to go out of your way to harm yourself to make BFR training dangerous.

Another common concern is that attempting to artificially increase the pump and the muscle recruitment could damage the muscles in some way. This is not the case.

Here you should remember that the same effect occurs when you perform many repetitions to muscle failure. BFR training just makes it last longer.

How to perform Blood Flow Restriction Training correctly

The first thing you need to know about BFR training is that it is only suitable for training arms and legs. There is no viable way to restrict blood flow to other muscle groups.

And the first thing you need to do is find a way to restrict blood flow.

For the arms you can use the medical bandages used for blood donation and intravenous injections and for the legs you can use the bandages you normally use to bandage the knees. There are now also numerous bandages specially developed for BFR training, which you can find online in many stores.

When putting on the supports, you should make sure that they sit as close as possible to the base of the arms and legs. For the arms, this means as close as possible to the shoulder and for the legs as close as possible to the hip.

As far as the tightness of the ligaments is concerned, this should be in the range of 9 out of 10 for the arms and 7 out of 10 for the legs. (Translator's note: Studies on the subject have shown that a tightness of 4 to 6 out of 10 is completely sufficient and is significantly safer and more effective than bands that are too tight).

Once you have the right tools and know how to use them, you can start your BFR training. There are a few things you should know:

Continue your current strength training program

Remember that BFR is a training technique that should be integrated into a well-planned training program. It should not be all you do.

Save BFR training for your supporting exercises

You should continue to start your training sessions with heavy multi-joint exercises. These are the primary building exercises that nothing can replace, which is why you should save BFR training for later in your training session.

More specifically, you should use BFR training with your supporting exercises, which are usually isolation exercises that you can safely perform to muscle failure. Examples would be dumbbell curls, leg extensions, tricep presses and leg curls.

Start with 3 to 5 BFR sets per training session with a weight that allows you 20 to 30 repetitions (about 50% of your 1RM weight)

I also recommend a 2-0-2 cadence, which means 2 seconds to lower the weight, no rest, and 2 seconds to lift the weight.

That's all you need to know about training execution.

Avoid these 4 BFR mistakes

As simple as BFR training can be, there are plenty of ways to mess it up. Here are the four most common mistakes I see when it comes to BFR training.

Mistake #1: Using BFR training before it's really beneficial

Studies have shown that beginners don't benefit from BFR training as much as experienced exercisers (12). The reason for this is simple:

When you've just started training with weights, your body responds very well to any training. It already reaches its anabolic maximum through proper nutrition and training, which makes BFR training superfluous.

For this reason, you can safely do without BFR training as long as you have less than a year of training experience. Stick to traditional training. Injuries are of course an exception here. If you are injured as a beginner, you can of course use BFR training to add some volume to your training while you recover from your injury.

Mistake #2: Tightening the bandages too tightly

Remember that you shouldn't be trying to cut off the blood supply. Instead, you just want to reduce the blood flow back to the heart. For this, the optimal range for tightness is 7 to 9 on a scale of 1 to 10.

Mistake #3: Using weights that are too heavy

You'll probably be surprised at how quickly you run out of steam when you do BFR training for the first time. For this reason, it's better to use too little weight than too much. Start light and gradually increase the weight until it is in the optimal range.

Mistake #4: Using BFR training exclusively instead of heavy training.

BFR training is not a substitute for traditional training with weights. Even though it produces more metabolic stress, it doesn't lead to much muscle damage or overload, both of which are more potent stimuli for building muscle.

And then there's the problem of exercise limitations. If you want to build a strong and muscular body as quickly as possible, then you need to focus on heavy key exercises such as squats, deadlifts, bench presses and shoulder presses, and BFR training is only possible with squats.

The bottom line on blood flow restriction training

Bodybuilding magazines love to recycle old training methods as groundbreaking news to help you build muscle faster than ever before. Most of these are overrated or of uncertain effectiveness.

BFR training, however, is a legitimate, science-based way to get more muscle out of your workouts.

On its own, it can produce results similar to those of traditional training methods - and when combined with traditional training, the overall results will be enhanced.

However, BFR training is not worth the effort if you are new to training with weights, as it will not have any noticeable effects.

However, if you are an experienced exerciser or if you are recovering from an injury or have limited equipment available, then you may benefit from this type of training.




By Michael Matthews

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