Vascular occlusion training (VOT) is a workout technique that slows the removal of blood from a particular muscle group by applying pressure to the muscle. Blood pressure cuffs or elastic bands are applied, such as above the biceps femoris, to occlude the blood vessels and decrease venous return. The purpose of this technique is to increase the accumulation of local metabolic byproducts. These compounds include lactate, IL-6, IL-15, and other "muscle molecules". They are not simply waste material, but are now understood to be potent stimulators of muscle growth and fat loss through intracellular and hormonal mechanism (4-12).
Review of vascular return
Unlike arteries, veins have low pressure. They are dependent on valves and both the contraction and relaxation of muscles to help return blood to the heart. Valves keep blood from flowing backwards, and moving muscles create a pumping action on the vessels to push blood forward.
Squeezing a muscle, like a bicep, causes a contraction that constricts the blood vessels. When the tension is released, the blood vessel relaxes. This contraction and relaxation when coupled together creates a pumping action with the valves, assuring blood moves in the right direction.
IL-6, IL-15, nitric oxide, and lactate are often thought of as detrimental compounds, unique to the immune or vascular system or simply waste products. However, they are each now known to have profound impacts on metabolism and are actually part of exercise's cascade of beneficial effects (4-12).
IL-6 when it is released from muscle can increase up to 100 times. Contrary to its effects when coupled with TNF alpha and IL-1 beta, IL-6 in the concentrations generated during exercise is anti-inflammatory (13). It raises levels of IL-10 and lowers TNF alpha and IL-1 beta by increasing soluble TNF alpha receptors and IL-1 receptor antagonists (7-8, 13). It also crosses over into hormone action increasing fat breakdown.
Il-15 is released from muscle during exercise as well. It is stimulated mostly by contraction of type II muscle fibers. IL-15, like IL-6, is hormone-like in action when released in the context of exercise. It increases muscle protein synthesis and fat breakdown (4-6).
Lactate and nitric oxide are both generated and released from muscle tissue where they can act in autocrine, paracrine or in the case of lactate, endocrine fashion (9,12). The signal sent by these molecules is an adaptation signal. They both increase mitochondrial synthesis. Lactate, in possible hormonal action (a receptor was recently discovered for lactate), stimulates both HGH and testosterone release (9,11).
Together, Il-6, IL-15, NO, and lactate are potent stimulators of metabolic adaptation. Muscular contractions under occlusion stimulate the metabolic accumulation of these compounds. This may lead to increased growth hormone production, increased activation of fast twitch muscle fibers and a host of other changes that increase muscle stimulation and growth.
Research on VOT
A recent study in the January 2010 issue of The International Journal of Sports Medicine reviewed the most recent understanding of VOT (3). The common dogma regarding weight training intensities for muscle growth dictate four to five sets of eight to twelve reps with a weight between 65% and 75% of a 1RM (a 1RM is a weight that can be lifted one time only, where the second rep is impossible).
This review highlights studies showing vascular occlusion with 45% to 55% lighter weights generates the same growth stimulus of traditional weight training protocols. This means vascular occlusion protocols may be able to bolster results while minimizing injury risk. This is an appealing tool when dealing with the frail and elderly.
Other studies have shown vascular occlusion greatly increases the production of growth hormone despite very light loads. Takarada et al. and Suga et al. have demonstrated this effect is coming through multiple mechanisms and includes metabolic accumulation possible through accumulation of the compounds mentioned above (1-2).
There are two ways to impose vascular occlusion. One way is to apply a tourniquet proximal to a muscle to slow the removal of blood and metabolic byproducts from the area. This is the way it is done in research. However, this method is not clinically viable for health professionals wishing to utilize the benefits of this stye of training.
There are different workout techniques that may be able to generate a similar effect. Manipulating muscular contraction is one potential solution. The idea is to use the squeezing action of a contracted muscle to "clamp down" on blood vessels and slow venous return. This may increase the metabolic accumulation of the key signaling molecules mentioned above.
Pulsing contractions (also known as inch reps, where the muscle is repeatedly contracted in a very narrow range while not allowing it to fully relax), or holding muscle contractions (where the muscle is squeezed hard and not released for a period of time) can act as the poor mans version of vascular occlusion. Bodybuilders have long used a form of this training called "tension reps" where resting top phase and bottom phase of a lifting exercise are removed. We believe the benefit enjoyed from this type of rep manipulation is also due to some degree of vascular occlusion.
There are several ways to use pulses and holds in your workouts. One option is to do a straight set and then a hold or pulse at the end. For example, if you are doing a bicep curl, you would first complete ten traditional repetitions. At the conclusion of the set and before resting, you would bring the weight to the middle of the range of motion (upper and lower arm at ninety degrees) then either hold by squeezing down hard, or pulse by squeezing hard and slightly relaxing repeatedly.
This holding or pulsing portion of the set should be held until the muscle reaches full fatigue. Burning in the muscle is a good indication the metabolic accumulation is occurring. The contraction occlusion method can be used in a number of ways. Pulses and holds have been mentioned, but very slow reps, partial reps, and any other method that manipulates and focuses the contraction of a muscle can work. These techniques are also easy to teach clinically.
Here is a quick beginner, simplified version of an "occlusion" workout:
- Choose two exercises for the three biggest muscle groups (Squats and leg curls for legs, chest press and DB chest fly for chest, lat pulldowns and rows for back).
- Do 3 sets of 10 for each exercise.
- At the end of each set do a 10 second hold followed by a 10 second pulse.
- Rest 1 to 2 minutes before going to the next exercise.
Example of tension rep push-ups: Get into a pushup position. Lower your chest just above the floor and then do a regular pushup with one minor change, do not let your elbows lock out. In other words, remove the bottom and top parts of the range of motion. Now do as many reps as possible within this narrow range of motion. As your muscles fatigue the range of motion will become more and more narrow until you are barely able to move at all. Hold that position for a period of 5 or 10 seconds.