A protocol called occlusion training, also known as blood-flow restriction (BFR) training, is one of the most interesting and effective trends in strength and conditioning. In studies, it has been shown to result in skeletal muscle hypertrophy, increased strength, and increased endurance. So how can we fit folks use it safely and effectively?
Occlusion training is simply a way of restricting blood flow in the veins of a working muscle in hopes to kick-start some larger gains in muscle size and strength. For example, you can wrap an elastic band around the top of your leg before doing your squat workout. It sounds crazy, and a little bit scary, but there's definitely something to it.
An article in the Military Times reported that one form of occlusion training, called Kaatsu, is "a revolutionary new training system" from Japan that is blowing fitness researchers' minds. Does that sound too good to be true? A little, right? Well, let’s take a closer look.
What is Occlusion or BFR Training?
During this workout, a specific type of tourniquet (similar to what a phlebotomist uses on your arm when you are giving blood) slows down the movement of the blood that is flowing back to your heart. This allows the limbs that are doing the workout to become engorged with blood.
This specific type of veinous occlusion significantly increases the concentration lactate in your blood, at lower workout intensity or weight. This, in essence, simulates the feeling of a much harder workout in the muscles while also tricking the brain into thinking the body is performing a very difficult workout. As a result, your pituitary gland (a tiny organ found at the base of the brain) releases more growth hormones (reportedly up to 170 percent more) along with hormones that are directly related to muscle hypertrophy (muscle growth) including IGF-1, MTORC1, and myostatin.
When lighter loads are combined with occlusion, you get bigger, faster—and without having to lift as heavy of a weight.
To achieve this veinous occlusion, you could, for example, tie elastic bands or exercise tubing or even an old bicycle tube around your upper arms before you do a set of dumbbell curls. Or before a set of squats or machine leg extensions, you can tie the elastic bands around your upper thighs. Then you do your workout as usual (with lighter weights than usual) and reap the benefits of your over-stimulated pituitary gland.
Occlusion training can and has been used by athletes, patients in postoperative rehabilitation, cardiac rehabilitation patients, the elderly, and even astronauts to combat atrophy.
How Does Occlusion Training Work?
By restricting the blood flow in and out of the working muscles you achieve what is called Cell Swelling, which is directly linked to muscle gain. That swelling, combined with a buildup of metabolites (or Metabolic Stress), has been shown to activate more muscle fibers—even at lower than usual intensities.
The three ways that BFR training is thought to work are:
The muscle cells become so full of fluid that they must grow (or burst)
The low oxygen level in a muscle during the accumulation of blood forces your body to recruit the larger fast-twitch fibers, which can stimulate more muscle growth
When oxygen is low, lactate rapidly accumulates, and many studies show that lactate (also known as lactic acid) can increase protein synthesis
A 2016 Sports Medicine systematic review found that occlusion training increased muscle size and strength in the shoulders, chest, and arms better than conventional training. In fact, the review concluded, “Current evidence suggests that the addition of BFR to dynamic exercise training is effective for augmenting changes in both muscle strength and size.”
In our body, muscles are made of two types of fibers: Type 2 & Type 1. Type 2 fibers are generally known as the fibers that grow easily. The trouble is that Type 2 fibers only really get involved in your resistance training workout when you go to all the way to failure or when you use very heavy weights. This is generally pegged at about 80 percent of your 1RM or 1 rep max (your 1-rep max is the most weight that you can lift once and only once).
So, when lighter loads (below 80 percent of your 1RM) are combined with occlusion, the Type 2 fibers are recruited much easier and earlier, allowing you to get bigger, faster and without having to lift as heavy of a weight.