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Back in 2007 I presented to readers the very first review of its kind on the controversial vascular occlusive training technique known in Japan as “kaatsu.” The idea of putting a tourniquet around a limb proximal to the muscle you’re training in order to purposely restrict blood from easily exiting the pumping muscle as a way to promote better growth definitely shocked some people.

In the late ’90s, Japanese researchers observed that performing only a lightweight training exercise while partially occluding blood fow using a tourniquet seemed to achieve similar or greater muscle growth and strength gains compared to those training with moderate to heavier weights but without the benefit of the tourniquet. Subsequently, Canadian researchers helped explain the reason behind this fascinating finding by showing that the vascular occlusion spurs greater neuromuscular motor unit activation.

The problem with kaatsu, however, as I cautioned readers back then, is that you have to be careful of the inherent risks of excessive and/or extended periods of vascular occlusion. When venous blood return to a pumping muscle is cut off, blood will pool, as intended. As a result, blood will more easily form clots that can break loose and even be fatal.

When a tourniquet is used to draw blood, it’s really only a matter of seconds up to a few minutes at most before the tourniquet is removed. So, could this technique cause blood clots? Could it damage muscle by excessively swelling the cells? Is this technique really useful?

To answer some of these questions, scientists Loenneke, Thiebaud, and Abe, et al., undertook a critical review of available evidence on the subject; they published their report this year in the Scandinavian Journal of Medicine & Science in Sports. Among their findings: 

In 2009, a study noted significant increases in delayed onset muscle soreness (DOMS) following kaatsu training. 

In 2012, another study looked at the acute effects of blood fow restriction on muscle activity and endurance during fatiguing dynamic knee extensions at low load. This study reported large reductions in force production following kaatsu training.

In 2013, researchers found that blood fow restriction did cause large acute muscle fatigue, but deduced it was not due to unhealthy damage because the result was not sustained.

And another study that same year looked at kaatsu training increasing acute determinants of hypertrophy without increasing indices of muscle damage. Similarly, in this study it was reported that the duration of muscle swelling after kaatsu was not excessively prolonged, thus indicating that there was no untoward muscle damage. So, in terms of negative muscle damage as a result of kaatsu training, there hasn’t been shown to be an issue. Also, among study subjects, no reports have been cited of peripheral blood clotting, central stroke, cerebrovascular incident, or pulmonary emboli.

So why aren’t bodybuilders raving about kaatsu training?

The answer probably has to do with the fact that, even if there’s some mild degree of efficacy and no real harm related to the use of kaatsu, the results aren’t enough to warrant the discomfort. It’s that simple.

Of course, if it isn’t enough of a mind-bend to try and fathom why researchers kept examining kaatsu despite its lack of popularity, try figuring out why they’re now combining it with vibratory stimulus to see if that makes muscles grow more easily. The vibrating plate, an early technology science hoped might—if carefully applied—help some subpopulation of elderly osteoporotic women was amped up and pulled into the fitness world, where the results are far less certain. With complaints like blurred vision, brain damage, hearing loss, back pain, and muscle strains, the vibration plate hardly became the fitness revolution it was hawked to be.

So, why on earth would anyone think to combine this silly technology with kaatsu? Probably because there’s an idiot born every minute. Of course, I don’t believe you can combine one impractical technology of little or no utility among athletes with another to somehow make a breakthrough. I tried kaatsu and didn’t see the benefits, but definitely noticed the discomfort and couldn’t wait to get the tourniquet off. When I tried exercising on vibrating plates years ago, it was quite challenging to squat and do exercises like pushups. But difficulty in execution doesn’t necessarily translate to better muscle stimulation. – FLEX