Thixotropy is nifty, but it’s not therapy

Occasionally I come across the dubious notion that massage is therapeutically effective because it softens tissues with “thixotropic effect” (Wikipedia). A quick look at how thixotropy works in human physiology shows that this just doesn’t make sense. The thixotropic effect is nifty physiology, but it’s not a therapeutic effect.

Thixotropy is an obscure physical property of some fluids, which become thin when agitated or stressed. You can easily simulate thixotropic effect in beach sand, near the water’s edge: stamp your feet in the sand, and it starts to liquify.

Thixotropic fluids in the human body include synovial fluid in joints, mucus, semen, and the gelatinous and poorly-named goo called “ground substance” — the stuff that gristly connective tissue fibres are embedded in like bits of coconut in Jello. Ground substance is the most plentiful thixotropic substance in the body.

The theory is that massage limbers you up by inducing thixotropic effect in your connective tissues. There are (at least) four things wrong with this:

1. Although thixotropy is indeed one of the reasons that we feel like we loosen up a little as we move around, it can only account for a small amount of “loosening.” Thixotropy makes connective tissues more pliable, not stretchier. The extensibility of tendons and ligaments is determined by the properties of the collagen fibres that give them their bulk and tensile strength, and they are (much) stronger than steel cable.
2. More importantly, who cares? The whole idea that it’s therapeutic to have “looser” connective tissue is bogus in any case. There are few therapeutic situations where you would actually want looser connective tissue, and even in those situations the problem could not be solved by thixotropy.
3. Even if it works in some small way, thixotropic effect is going to be temporary, fading within seconds or minutes after hands are removed. When the stimulation stops, so does the thixotropy.
4. Last but not least, thixotropic effect is simply minor, occurring all the time with or without massage. Massage undoubtedly does induce it, but almost certainly less than ordinary physical activity (just like with circulation).