That guy at the gym with the elastic bands wrapped around his arms... what's up with that?
It's possible he just had his blood pressure taken and forgot to remove the pressure cuff, but it is more likely he is engaged in occlusion training. Also known as blood flow resistance training (BFR), it is a form of weight training in which blood flow to the veins is obstructed, causing to it to pool in the occluded limb.
Developed in 1970s Japan (where it is known as “kaatsu”) BFR involves wrapping a device like a pressure cuff or large rubber band around the top of a limb at a pressure sufficient to occlude blood flow to the veins, but not the arteries. This way, the arteries continue to deliver blood to the limb, and as the veins struggle to take it back to the heart. The result is more muscle mass in less time.
What's the science? It is not 100 percent clear, but it likely involves “metabolic stress.” This is the process in which training byproducts called metabolites – which include include lactate, inorganic phosphate, and hydrogen ions – build up when oxygen is low. This accrual in turn enhances protein synthesis and satellite cell activation – key elements needed for muscle growth.
The accumulation of blood also prompts your body to recruit larger fast-twitch fibers. It is this class of muscle which have the largest contractile area and the ones the body uses specifically for “high burst” activities like sprinting and power lifting. In the sport of body building, these are the muscles that win you the trophies.
It may sound a little crazy, but it works, so let's get started!
You don't need fancy, specialized “Pro Occlusion Training Wraps,” but we're sure there is a sporting goods store somewhere that would love to sell some to you. Instead, use knee wraps for the legs and wrist wraps for the arms. Tighten them to what you would perceive to be a 7 on a scale of 1 to 10 for the knees, and 5 to 6 for the arms, where 10 is the tightest your could ever conceive of tightening. (Wrap too tightly, and you may occlude the arterial blood flow as well, and that's a Bad Thing.)
Now... go light. The research indicates that there's no benefit to be gained from using heavier weights for BFR. Choose a weight that is 20 to 40 percent of your normal routine. (It'll feel a lot heavier!)
Health Sciences professor and body builder Jacob Wilson recommends 4 sets with reps of 30, 15, 15, and 15, with only 30 seconds rest between sets. Perform this workout 2 to 3 times per week, for optimal growth.