Occlusion training is also called blood flow restriction training (BFR). The goal is to decrease the time it takes to build strength and muscle size.

The basic technique calls for restricting blood flow to a muscle that you’re exercising for the purpose of building its strength and size.

Using elastic wraps or pneumatic cuffs, you reduce the movement of blood flowing back to your heart so the body part you’re working out becomes engorged with blood.

For example, you can tightly wrap your upper arms before doing dumbbell curls to work out your biceps — the muscle on the front side of your upper arm.

This occlusion (blockage) of the vein increases your blood’s lactate concentration. You can work out at a lower intensity while giving the feeling of a much harder workout.

When your brain thinks your body is experiencing a difficult physical challenge, it signals the pituitary gland to release more growth hormones and hormones that respond to muscle growth, or hypertrophy.

A 2014 review concluded that occlusion training led to no prolonged reduction in muscle function and no increase in indications of muscle damage appearing in blood tests.

The review also indicated that muscle soreness was similar to traditional workouts and that there was no extended muscle swelling.

There’s always a risk when you’re using a tourniquet-like procedure, such as an occlusion cuff, for limiting blood flow.

The size of the band or cuff and the amount of pressure it exerts have to be properly sized and aligned with placement on the body and duration of use.

For example, a 2012 study of 116 people indicated that there was a measurable difference in using narrow or wide cuffs in BFR training. The wide BFR cuff restricted flow at a lower pressure.

In clinical settings, resistance training using moderate to high loads often isn’t possible.

By using occlusion training, loads can be significantly lowered while still getting acceptable levels of muscular strength and growth.

This is without, according to 2016 study, the cardiovascular risk and high levels of joint stress associated with heavy-load training.

According to a 2017 article, BFR can be considered an emerging clinical modality. The article indicated that more research should be done to establish protocols for safe use.

Current research suggests that occlusion, or BFR, training can be a safe and effective way of increasing muscle strength and size.

As with the adoption of any new exercise, check with your doctor to see if BFR is appropriate for your level of health and physical abilities.