I often come across the dubious notion that massage is therapeutically effective because it softens tissues, especially fascia, with “thixotropic effect.” A quick look at how thixotropy works in human physiology shows that this just doesn’t add up. The thixotropic effect is nifty physiology, but it’s not a therapeutic effect in itself, nor is it the mechanism of one. It was never more than an idea that Ida Rolf had in the 70s about how here therapy method (Rolfing) supposedly worked — and Ida’s idea was wrong.
Thixotropy is an obscure physical property of certain slimy body fluids that get thinner when agitated or stressed. You can easily observe 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.
What makes these substances gooey and slimy? Why, a family of carbohydrate molecules, of course: the glycosaminoglycans. Also known as the snot molecule. Think of any movie monster with tons of ropy saliva — that’s glycosaminoglycans!
The therapy theory of thixotropy is that massage limbers you up by inducing thixotropic effect in your connective tissues. In particular, Ida Rolf used thixotropy to explain fascial “releases.” Robert Schleip is a researcher who is known for his focus on the properties of fascia:
Many of the current training schools which focus on myofascial treatment have been profoundly influenced by Rolf (1977). In her own work Rolf applied considerable manual or elbow pressure to fascial sheets in order to change their density and arrangement. Rolf’s own explanation was that connective tissue is a colloidal substance in which the ground substance can be influenced by the application of energy (heat or mechanical pressure) to change its aggregate form from a more dense ‘gel’ state to a more fluid ‘sol’ state.
Schleip, “Fascial plasticity: a new neurobiological explanation,” Journal of Bodywork & Movement Therapies, 2003
But thixotropy is minor, slow, and temporary, and fascia is too tough to change.
Fascial sheets are incredibly tough, and you can’t “change their density and arrangement” quickly or easily. And thixotropy just isn’t fast enough to explain the relatively speedy, dramatic effects on tissues that therapists claim to achieve. Dr. Schleip: “either much longer amounts of time or significantly more force are required for permanent deformation of dense connective tissues.” Thixotropy might make connective tissues more pliable, but 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. When the stimulation stops, so does the thixotropy, and a therapy can’t work if the affected tissue immediately reverts to its previous state.If thixotropy had the power to increase the extensibility of connective tissue, then we would become obviously more flexible just from sitting in a sauna — I’ve tested this repeatedly, and never observed any increase in flexibility just from being hot.
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, and a therapy can’t work if the affected tissue immediately reverts to its previous state. Dr. Schleip calls this the “reversibility problem” and “definitely not an attractive implication of this model for the practitioner.”
Last but not least, thixotropic effect is simply a minor effect. It’s occurring a little bit all the time, with or without massage. Massage surely does induce it a little, but just as surely much less than ordinary physical activity — like with circulation. Massage therapists are very fond of claiming that massage “increases circulation,” but if it does so at all, the effect is much smaller than what exercise does! Perspective matters. Another similar thought experiment: if sustained pressures or sheering could significantly change connective tissue, then working a chair all day long — or any long-duration posture — would also deform your fascia.
Most importantly, who cares? The whole idea that it’s therapeutic to have “looser” connective tissue is also obsolete. 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.
I am a science writer, former massage therapist, and assistant editor of Science-Based Medicine. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook and Google, but mostly Twitter.
A slightly different version of this article is used as a chapter in a much longer article about fascia: