Vascular occlusion (VO) training or muscle occlusion training (also known as abbreviated blood restriction training) is an exercise approach involving the compression of the proximal vascular system to the active muscles to reduce venous return of the limb, which which causes venous accumulation. Longer terms also include a blood flow moderation exercise or a vascular occlusion moderation workout.
VOT and associated methods have gained popularity primarily as an alternative to the principle of progressive loading in specific weight training of hypertrophy, although more recent studies show superior results over simple strength training. VOT is nevertheless suggested as a possible solution to acquire muscular hypertrophy in “stubborn” body parts such as calves.
Although following a similar dynamic, VOT has two different modes of occlusion induction on the vascular system. The first method is to apply a simple tourniquet close to a muscle. Yet another method is the manipulation technique of muscle contraction.
When using belts and lifting straps for the tourniquet, the amount of pressure on the vascular system can not be controlled and there are case reports of rhabdomyolysis due to VOT. Sato himself risked his life in 1967 after uncontrolled sessions of VOT, leading him to focus more on controlling and adjusting the pressure applied to the vascular system.