Image may be NSFW.
Clik here to view.
Usually in the purpose of hypertrophy, a minimal load of 65% 1RM and the repetition number 8-12 is recommended. Occlusion training (OT) is an interesting concept that under certain conditions allows similar results by doing a training with significantly lower intensity.
Occlusion in this context means closing, or limiting the venous flow in a limited area. Other name that is used is “blood flow restriction training” (BFR).
The basic principle is that venous flow is limited in the trained muscle. At first it sounds bizarre and extreme, but you must admit there is some logic to it. Namely, venous flow is a drainage component which drains blood from a muscle and by keeping the blood in the muscle we get the pump effect which leads to hypertrophy (of course, if we fed the muscle and renewed it’s energy after the training). Furthermore, OT manages that with significantly lower intensity.
Historically, in 1996. the first person who thought of that was a Japanese scientist Yoshiaki Sato who called this method Kaatsu training. During one Buddhist rite Sato kneeled for so long that he stopped the bloodflow in his calves. The feeling that he had in his calves then, he compared to the one after an intense training of the calves. Sato also described that this kind of training is extremely risky and dangerous after being hospitalized himself. He wrote: “When too much pressure is applied, the skin can grow pale and if we continue with the training, thrombosis can occur.”
What are the effects of OT on a muscle?
When the main goal is hypertrophy, pump is a word that defines success. But that is not the only effect of OT. In standard conditions, slow triggering fibers (type I) activate first, and fast triggering ones (type II, the ones that are important to us) are activated only with high intensity of the training.
In the conditions of OT, slow triggering fibers are activated with low intensity as well, because with limited bloodflow slow triggering fibers (aerobic) get exhausted earlier. This has also been confirmed with electromyography (EMG).
Metabolically viewed, with this kind of training acuumulation of lactate is increased, which as we already know, is proven to increase the concentration of growth hormones. The next effect is increased migration of satellite cells that will differentiate into myocytes. Besides that, a considerably lowered expression of genes responsible for myostatin synthesis has been noticed. It is also speculated that with this kind of training mTOR signalization is increased (one of the ways with which the cell is stimulated to an increased synthesis of protein=growth).
OT in practice
This principle can be used only for extremities, so for thigh, shank, upper arm and forearm muscles. Elastic bandage is used for wrapping, or for knees and wrists elastic tape. The wrapping is placed in the most upper part of the muscle that we are training.
The first and basic rule is not to tighten it t the point where besides the venous flow, arterial is reduced too. Key word is to limit not to stop the venous flow. It is important to wrap it in a narrow area. Wrapping in a wider area increases the risk from limiting the flow in the arteries! It should be tightened to around 70% of the maximim, so we can limit and not stop the flow.
I already mentioned that with this training a lot lower loads (intensities) are used than with standard training. So, the load that you work with is 20% 1RM (this is not an error!). In every exercise 4 series of 30, 15, 15 and 15 repeats are done. Rest between series is 30 secnds. During all this time the bandages are not removed. They are removed only after the training is over and then the venous flow is normalized.
Note that in this type of training should be approached very cautiously because it is easy to overdo the tightening and instead of progress in hypertrophy it can go in a completely opposite direction. There is an example of a Norwegian athlete that was admitted to a hospital with the feeling of excruciating pain two days after BFR training of quadriceps. The value of enzyme creatin kinase in his blood was 12400 u/l (normal values are 52-336 u/l). That kind of state means rhabdomyolysis, or discharge of myoglobin from the muscles in such an extent that can cause kidney failure.
Wisely applied, however, it can be very useful to people that are coming back after some injuries and can’t load the joints with too much pressure. It is also applicable for someone who cannot train with a high intensity for whatever reason, to keep or gain muscle mass.