Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "
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14.02.2009 |
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Restricting blood flow makes muscles grow
The Japanese have been doing research for a while on training muscles at low level intensity with reduced blood supply to the muscles. They hope that under these conditions muscles grow faster and that 'training with restricted venous blood flow', as it is called, can help people who can't do ordinary strength training to build up strength. Old people, for example.
Strength training only 'works' with a load that is at least 65 percent of the 1RM. 1RM is the maximum amount of weight you can lift properly for only one repetition.
The researchers fitted their test subjects with a belt that restricted the blood supply to the legs, and then set them to walk on a treadmill. The photo above shows the set up. The control group walked without having their blood supply restricted.
The researchers also measured free testosterone, IGF-1 and its binding proteins, and muscle damage markers. They found no effects.
The treadmill training did lead to a dramatic growth in muscle tissue, as the graph below shows. Kaatsu-walk = walking with restricted blood flow.
The photos below are from MRI scans. The upper photo shows the results of scan of the two legs of a test subject before the experiment started. The lower photo is of a scan of the legs of the same person at the end of the experiment. Quod erat demonstrandum, as they say in Asterix and Obelix.
Oh yes.
The test subjects got stronger by walking with belts tied around their upper thighs.
Exactly how the anabolic effect of training with restricted venous blood flow works, the researchers don't know. The theory they put forward is that restricting the blood flow to the muscle cells activates the glucose transporter GLUT4. But they don't have much evidence to support this theory.
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