You might have heard of "kaatsu" or tourniquet training. It's a training method that relies on lifting light weights (20-30% of your maximum for 15-30 reps) while wearing a special cuff that's tightened up around the proximal end of a limb to restrict blood flow to the muscle.
Studies have shown that despite the light weights being used, the muscle growth response is as big as lifting heavy weights (80% and more). The reason is the blood occlusion, which has been shown to create a deprived oxygen state (since blood flow to the muscle is limited, so is oxygen transport). This leads to an accumulation of lactate which increases the production of both hGH (growth hormone) and IGF-1 (Takareda et al. 2000).
The lack of oxygen (hypoxic state) and increase in acidity has also been shown to increase the recruitment of fast-twitch muscle fibers (Shinohara and Moritani, 1992). In fact, oxygen restriction to the muscle increases fast-twitch recruitment, firing rate, and spike amplitude (Yasuda, 2005).
Finally, exercise with restricted oxygen/blood entry in the trained muscle also leads to the production of Reactive Oxygen Species (ROS), which increase muscle satellite cell activation and proliferation (two key phenomenon involved in the muscle growth process).
The good news is that you don't have to use kaatsu training (which can be risky) to create this oxygen/blood flow restriction to the muscle. Sustained muscle tension (as in never allowing a muscle to relax during a set) can make muscle hypoxic even without external occlusion (Bonde-Peteron et al. 1975, Mitchell et al. 1980).
IMO kaikki kannattaa aina hyväksyttää Hulkilta, ennenku alkaa tekemään mitää :D
