Kaatsu is a controverse training method surfacing every other year as the one to go for for extra muscle growth. Can it work and is it safe?
Squeeze Me Baby One More TimeTo stimulate muscle growth your muscles need incentive to grow. And that incentive comes via using weights that push the muscles to the limit.It's the mantra every workout program focused on increasing muscle mass is based upon and mountains of reliable research back it.But twenty years ago Japanese researcher Yoshiaki Sato patented a very different method. He says you only have to put a tourniquet on your limb and then use a weight no heavier than joggers use as ankle weights. This, Sato claims, gets you the same effect as with heavy weights.
Blood Flow Restriction TrainingHe called it "blood flow restriction" or "Kaatsu" training (Japanese for "extra pressure"). And indeed, a number of studies found that it works:
- A 2000 study used blood flow restriction training on older women and found it gave them as much hypertrophy as regular weight training
- In a 2002 study, 17 fully trained rugby players experienced strength increases they were unlikely to reach with regular workouts
- A 2005 study recorded that Kaatsu increased levels of several hormones important for muscle growth
- A 2006 national survey in Japan stated that Kaatsu centers were highly satisfied with the training method
Blood Clots And EmbolismThe biggest is thrombosis - blood clots that block blood flow in a vessel. In really bad cases the clot loosens, travels toward the heart and seals off a major vessel. The result is a stroke or "pulmonary embolism" and death turning into a realistic possibility.Sato himself experienced this (PDF) when he started experimenting with restricting blood flow in the 1960s:
Numbness in my leg due to my reckless Kaatsu training routine became so severe that I was hospitalized. Up to that point I had ignored the numbness in my legs during training and continued with my training despite the discomfort. At one point, however, I began experiencing an acute attack of shortness of breath. I went to the emergency room and was diagnosed with a pulmonary embolism.In the few cases where professional athletes experimented with blood flow restriction training, exact vein location was established through ultrasound, doctors applied the tourniquets and monitored participants. That's not something you can do at the gym or at home.