Blood flow restriction (BFR) training, also known as occlusion training, is a newer training methodology using cuffs or wraps placed around a limb during weight training. These wraps allow for arterial inflow of blood into the working muscle with inhibiting venous return. BFR training forces blood to stay inside your muscles longer than normal, which influences muscle physiology in several ways.
During weight training, metabolic waste products accumulate in your working muscles. Blood is responsible for clearing these metabolic byproducts from your working muscles and supplying them with oxygen and nutrients to allow them to continue functioning at a high level. BFR training slows the rate at which these waste products are cleared from your muscles, allowing them to stay around longer, thereby eliciting a more greater anabolic effect in your body. In other words, by restricting blood flow, you’re amplifying the effects of metabolic stress in your muscle cells, which results in better growth after training.
Research has shown that BFR training increases mTOR and lowers myostatin levels in the body which creates an environment that is ideal for muscle growth.[2,3] In case you weren’t aware, myostatin is a protein that inhibits muscle cell growth and differentiation. By rendering myostatin inert, you’re removing another impediment on the pathway for making gains in size and strength.
Resistance training also forces cells to swell and expand with nutrients and fluid, which also happens to be another signal for muscle growth in your body. Occlusion training increases this “cellular swelling” and lengthens the amount of time your cells stay swollen, which tells the body the muscles need to grow bigger to adapt to the increased metabolic stress.