So last week we saw what happens at the level of the collagen in the perimysium (the deep fascial covering around the outside of muscles, encapsulating them like cling film) when we don’t move, and all at breathtaking speed! But there’s another aspect which must be taken into consideration, and that’s the reaction of hyaluronan (otherwise known – wrongly! – as Hyaluronic Acid. Turns out it’s NOT an acid! Who knew?! ).
Just to give you a bit of background, hyaluronan is produced by fasciacytes. The most common of the proteoglycans in the extracellular matrix, it has a high molecular weight and an uncanny ability to bond to other proteoglycans, forming “macromolecules”. Its functions include lubrication, which enables gliding between opposing surfaces. Its concentration and temperature are among the physical parameters that determine the density of the matrix.
Hyaluronan occurs throughout our fascia but is especially prominent in the deep fascia, in the loose connective tissue layers between the bands of densely-packed collagen fibres. These strata are actually visible with high-powered ultrasound so the quality and quantity of gliding can be observed. This can vary widely between symptomatic and asymptomatic subjects. Any deviation from the normal configuration of the hyaluronan can alter the behaviour of the entire deep fascia and its underlying muscle. This can drastically affect movement and may just explain “myofascial pain”!
Mary Cowman, Antonio Stecco and their team at NYU (Langone Health) have identified a remarkable trait of hyaluronan in that it self-aggregates when under- or indeed over-stimulated! In the case of underuse, immobility causes increased retention and reduced degradation of this substance. This changes the viscosity – or stickiness – of the fascia, so vastly reducing glide function. We’ve all experienced this when we’ve been sitting for an extended period of time, causing that sense of stiffness in our calves for example. And this regardless of how much exercise/movement we have done beforehand! SO, GET UP AND MOVE!