Simply put, BFR training is an advanced strategy, which makes use of weightlifting cuff straps or wraps tied around a limb during exercise. The goal is to restrict the blood flow out of that limb, whilst still allowing arterial circulation. This means that blood is able to enter the muscle, but struggles to leave.
Other names that BFR is known by are Vascular Occlusion Training (VOT), Hypoxic Training & KAATSU.
All About The Metabolites
The idea behind BFR training is that by restricting the blood from leaving the limb (venous return) it will also keep the byproducts of training in the muscles. These byproducts are known as metabolites and some of them are absolutely necessary for muscle growth. For example, Lactic Acid.
It has a bad reputation as a waste product responsible for muscular fatigue. Lactate actually has a strong anabolic effect and serves a signalling molecule for hormones responsible for muscle growth. It has been shown to have an enhancing effect on satellite cells, muscle protein synthesis and even testosterone – all of which are key elements in building muscle.
Research shows that hypertrophy (muscle growth) can be achieved at much lower intensities when using the BFR strategy. This is potentially attributed to the increased production of growth hormone (GH) in the body during BFR training.
According to the American College of Sports Medicine (ACSM) guidelines, lifting weights at least 70% of your 1RM usually produces the greatest muscle building effects. Some studies have found that BFR training produced muscle growth at intensities of 50% of 1RM or less! This makes BFR a very appealing rehabilitation strategy for injuries, often prescribed by physiotherapists to allow the patients to increase their strength and muscle mass without putting heavy mechanical loads on the damaged tissues (muscles, tendons, ligaments).
The primary factors in building muscle are mechanical tension and metabolic stress. BFR has showed that despite the low level of mechanical load (<50% of 1RM) it can improve muscle growth by improving fast-twitch fibre recruitment, systemic and localised hormone production, cell swelling and others.
How Do You Do It?
As mentioned earlier, BFR is an advanced training strategy and should not be attempted without qualified supervision at first.
Two of the most commonly used BFR training methods are:
- KAATSU Band – A specialized device that, according to the manufacturer can be used safely by athletes and non-athletes of every age and ability. It works as an inflatable or fastenable band that is clipped around the ‘top of the limb’ (proximal). The device restricts venous return, making the blood ‘pool’ in the limb. The advantage of this device is that it gives you precise control over the pressure and tightness at all times.
- Elastic Wrapping – You will often see powerlifters using elastic wraps around the knees or elbows. Although the main purpose of wraps is performance enhancement or pain relief, new uses have been discovered. Using these to restrict blood flow by tieing them around a limb may be a practical and cheap option, however they may restrict both the arteries and veins. Research has shown a decrease in muscle growth, when the area has been wrapped too tight as a result of restrict arterial occlusion (blood coming in).
Below we have added a guide to give you a better idea of the do’s and don’ts when preparing for BFR training: