By Robert Schleip, PhD, Certified Advanced Rolfer™

ABSTRACT The human body is by majority made of water, specifically interstitial water dissolved in our extracellular matrix. Easy flow of water through the lymph system is associated with healthy tissue and in vivo studies describe this water flow as moving through channels in the ground substance. Dr. Schleip discusses the molecule hyaluronan and the discovery of the ‘fasciacyte’. Tissue water distribution is reviewed in relation to manual pressure, movement, and induced shearing forces.

Editor’s note: This is an excerpt from Chapter 9 – Water and Fluid Dynamics in Fascia – by Robert Schleip from the forthcoming Second Edition of Fascia in Sport and Movement (Robert Schleip and Jan Wilke, Eds.), Edinburgh: Handspring Publishing, 2021, used with permission. We have made modifications for our journal style.

The Miraculous Capacities of Hyaluronan

The ground substance is mainly composed of proteoglycans, most of which are hydrophilic (i.e., water loving), and of bound water. Similar to the structure of a bottle brush, or of plant mosses, the proteoglycans are arranged in a geometrical manner, thus offering the largest possible surface area for water molecules to attach to. Within the proteoglycan aggregates, hyaluronan often serves as a core protein, to which glycosaminoglycans are connected (see Figure 1A). Hyaluronan is one of the most hydrophilic molecules in nature: it can trap up to 1,000 times its own weight in water! Therefore, a high concentration of hyaluronan tends to increase the water content of a tissue.
One of the most exciting discoveries in the field of fascia science in recent years

Hyaluronan is one of the most hydrophilic molecules in nature: it can trap up to 1,000 times its own weight in water! Therefore, a high concentration of hyaluronan tends to increase the water content of a tissue.

has been the reported existence of a new connective tissue cell type, which seems to be primarily focused on a rapid production of hyaluronan. A team of researchers at Padova University suggested the name ‘fasciacyte’ for these cells, which they describe as expressing a rather round cell shape, in contrast to the spindle-like shape of regular fibroblasts. They also showed that this cell type is frequently found in the upper and lower portions of loose connective tissue layers, i.e., at their transition to denser fascial layers adjacent to them (Stecco et al. 2018).
Hyaluronan is usually considered to be a lubricant, indicating that it decreases friction between adjacent tissue layers. This function is supported by a recent histological study, in which it was shown that the concentration of fascial tissues, which are exposed to a large degree of shearing/sliding motions, express hyaluronan concentrations of up to 10-fold higher compared with fascial tissues that are exposed to very little deformation (see Figure 1B). This suggests that providing a fascial region with regular shearing motions could induce a higher hyaluronan concentration in this region. To date, no studies have compared the value of regular stretches of the muscles and fasciae in the face with the reportedly beneficial effect of external cosmetic hyaluronan injections. However, given these general interactions between shearing motion and the production of hyaluronan within the tissue itself, it would not be surprising if the ‘internal treatment’ could at least compare with the external one.
Interestingly, hyaluronan can also function as a ‘sticky glue’, preventing easy sliding between adjacent tissue layers. This apparently happens when hyaluronan takes on the form of super molecules, which are multiple times larger than in the usual molecular condition of this substance. There are indications that this glue-like condition, also described as an increase in viscosity, tends to happen more frequently when there is an acidic condition in the ground substance. It also happens when the tissue is exposed to repetitive mechanical overloading, such as in exercise or in repetitive strain injuries. While these changes may lead to a local stiffening and a decrease in range of motion in everyday living, an increase in tissue temperature tends to break down the large molecular structure into small er fragments, which then express a much lower viscosity than in the previous condition (Pavan et al. 2014).
Similarly, it has been shown that the glue- like viscosity can be easily reduced with appropriate mechanical loading. While the application of sudden pressure tends to be ‘ignored’ by the tissue, it has been shown that shearing motions, which induce a twisting/bending inside of the fibrous architecture, together with gradual redistribution of internal pressures, tend to induce a significant decrease of viscosity. This might explain why immobility reduces fascial gliding and, consequently, range of motion. It may also explain the beneficial effects of many therapeutic myofascial release treatments (Pavan et al. 2014). A similar mechanism may also be at work when experiencing a beneficial effect in terms of a reduced tissue rigidity induced by regular movement practices

While the application of sudden pressure tends to be ‘ignored’ by the tissue, it has been shown that shearing motions, which induce a twisting/bending inside of the fibrous architecture, together with gradual redistribution of internal pressures, tend to induce a significant decrease of viscosity.

in daily life. The beneficial response of such ‘warming up’ exercises may then be partly comparable to the well-known response of shaking a ketchup bottle, which induces a decreased viscosity (or increased fluidity) in its content.

Soaking Up the Water

A healthy body will prevent the hyaluronan (and other hydrophilic elements within the ground substance) soaking up excessive amounts of water, since this would go along with a dramatic expansion of the total volume of the respective tissue. This healthy restraint is achieved by a constantly pre-stretched condition of the local collagen fiber network, which prevents the proteoglycan inducing an exaggerated tissue expansion (see Figure 2). A simplified description is that in a healthy body condition, the proteoglycans are always ‘thirsty’. It is only in the case of injury, or other pathological changes, that they can soak up as much water as they would like to and then expand beyond their previous restrained condition. This can be easily observed in a fresh ankle sprain injury: here, the clearly visible tissue swelling often occurs during the first few minutes.
Based on this consideration, it appears rather unlikely that one could influence the water content (and pre-stretch) within dense fascial tissues just by drinking more water during the day. In other words, the water content in your ankle retinaculum will be primarily regulated by the pre- stretch of the local collagen network. Once that network expands, as in a fresh injury, the proteoglycans will soak up as much water from the arterioles as they want to, independently of how much water the person had been drinking that day. Another consequence of the described pre-stretched situation in healthy tissues is that any additional uptake of water into the ground substance will probably happen via an altered fluid-pull (suction) from within the ground substance, not by an increasing supply (push) of water from the outside into the pre-stretched tissue.

Squeezing a Sponge: Dynamics of Dehydration and Rehydration

When exposed to mechanical loading, the water content in a fascial tissue tends to be decreased: similar to the deformation of a wet sponge, once it is either stretched or compressed, some of the internal water content will be squeezed out during the loading condition. Similarly, after the loading is stopped, the sponge is expected to rehydrate again, with either the same water or with new water from within the vicinity. Our laboratory at Ulm University demonstrated this sponge- like dehydration and rehydration effect multiple times in an organ bath condition

(Schleip et al. 2011). We also showed that the loading-induced dehydration tends to go along with a temporary loss of tissue stiffness (at least in ligamentous tissues), and that the subsequent rehydration tends to restore the previous tissue stiffness again (see Figure 3). A similar effect has been documented with a foam roller-like myofascial treatment on the plantar fascia (Frenzel, Schleip, and Geyer 2015) and with therapeutic application of a Rolfing® myofascial release technique on the lumbar fascia (Dennenmoser, Schleip, and Klingler 2016).
Interestingly, our organ bath experiments indicated that a ‘supercompensation’ effect can be achieved if the magnitude of the tissue loading is large and the subsequent rest period is sufficiently long. This ‘strain hardening’ could be observed in some cases, when a subsequent increase of stiffness beyond the original condition was induced. If the supercompensation could also be shown in vivo, it might provide future applications for preconditioning routines in athletic performance conditions (Schleip et al. 2011). Because hydration changes can impact the failure stress of at least some fascial tissues (Werbner, Spack, and O’Connell 2019), a more detailed investigation of the various interactions between different mechanical loading protocols, resultant hydration changes and subsequent effects of biomechanical tissue properties provides a very promising area in current research.

Liquid Crystals Within Us

Ubiquitous on earth, water is present in all life forms. However, recent research has revealed that the water inside of living bodies exposes very surprising properties, which are certainly different to what has so far been known about regular bulk water.
The basic idea that ‘interfacial water layers’
– i.e., the arrangement of water molecules in the vicinity of biological surfaces – play a fundamental role in biological systems was proposed in a visionary paper by Szent-Györgyi (1971). As Gruebele, one of the leading scientists in this area, explains: “Water in our bodies has different physical properties from ordinary bulk water, because of the presence of proteins and other biomolecules. Proteins change the properties of water to perform particular tasks in different parts of our cells. Water can be viewed as a ‘designer fluid’ in living cells” (University of Illinois

at Urbana-Champaign 2008). Apparently, the interaction of water molecules with hydrophilic and hydrophobic biomolecules in their vicinity influences their behavior in very surprising manners. Gruebele states: “We previously thought proteins would affect only those water molecules directly stuck to them . . . Now we know proteins will affect a volume of water comparable to their own. That’s pretty amazing” (University of Illinois at Urbana- Champaign 2008).
Pollack (2013) examined the behavior of what he calls ‘vicinal water’ within the temporomandibular joint and described it as a crystalline architecture. While the water molecules in this state still vibrate very rapidly in this condition, they do so within very stable conditions, which are called ‘liquid crystal’ in physics (Pollack 2013). Because of the previously described ‘bottle brush architecture’ of the proteoglycans in the ground substance of fascial tissues, a large proportion of the water molecules apparently take on this special crystalized condition. As Pollack (2013) states, “The combined data from three different methods lead to the conclusion that all or almost all of the water in the intact disc is bound water and does not have properties consistent with free or bulk water.”
The crystalized water exposes very different properties to regular bulk water in terms of a significantly different density, an increased viscosity, different light transmission and a different electrical conductance (Sommer et al. 2011). Note that while most of the proteoglycans are hydrophilic, the small elastin fibers are hydrophobic. Their strong water repulsion then induces a coating-like accumulation of specially arranged water molecules around them, in which these molecules’ binding sites face away from the fibers, and thereby take on a crystalized condition not unlike the vicinal water around hydrophilic surfaces. While it is a common assumption that morphological differences in aging skin are due to a change in the elastin fibers, Sommer et al. (2011) demonstrated that the amount of water coating around these fibers plays a major role. While the elastin in young fibers is surrounded (and buffered) with a very thick zone of crystalized water, this

‘Interfacial water layers’ – i.e., the arrangement of water molecules in the vicinity of biological surfaces – play a fundamental role in biological systems . . .

coating tends to get thinner and thinner as we age, due to the accumulation of free radicals and other metabolic waste products in the small vacuum-like zone between the fibers and their coatings. In an intriguing experiment, Sommer and Zhu (2008) showed that after an attempt to push the ‘dirty bulk water’ away from this zone using a special laser, the elastin fibers were apparently surrounded again with thicker coatings of crystalized water and the skin in these regions took on an obviously more juvenile appearance (see Figure 3).
Inapersonaldiscussionwithourdepartment, Dr. Andrej Sommer and his Rolfer colleague, Dr. Kai Hodeck, expressed an assumption that a mechanical sponge-like myofascial treatment, in which the inherent water is steadily pushed into different directions, could potentially exert a similar (or even stronger) renewal effect on these water coatings than the one reported in their study. If this speculation were supported and validated by future investigations, it would mean that regular stretching, foam rolling or similar treatments could induce a higher proportion of crystalized water in the ground substance and, thereby, induce and exert an anti-aging effect on the tissues. It will be exciting to follow the ongoing research of these pioneers and their col- leagues in the next few years.

Clinical Summary

Water constitutes the majority of the volume of our fascia. Any change in this element can be expected to exert significant effects on the whole tissue. For movement therapists, it is helpful to think of the sponge-like changes of their interventions. A skilful interplay of temporary dehydration and subsequent rehydration promises not only a renewal of the tissue, but may also change the stiffness of the treated area. Applying mechanical pressure may also induce a change of the viscosity via a molecular change of hyaluronan. Lack of motion, on the other side, will lead towards a more rapid aging effect, which probably is associated with a decrease of crystalized water within the tissue.

Robert Schleip, PhD (human biology) has been certified as a Rolfer since 1978. He is Research Director of the European Rolfing® Association and is also Director of the Fascia Research Group of Ulm University, Germany.

References

Chaitow, L. 2009. Research in water and fascia. Micro-tornadoes, hydrogenated diamonds & nanocrystals. Massage Today 9:1-3.
Dennenmoser, S., R. Schleip, and W. Klingler. 2016. Clinical mechanistic research: Manual and movement therapy directed at fascia electrical impedance and sonoelastography as a tool for the examination of changes in lumbar fascia after tissue manipulation. J Bodyw Movem Ther 20:145.
Fede, C., A. Angelini, R. Stern, V. Macchi,
A. Porzionato, P. Ruggieri, R. De Caro, and C. Stecco. 2018. Quantification of hyaluronan in human fasciae: Variations with function and anatomical site. J Anat 233:552–556.
Frenzel, P., R. Schleip, and A. Geyer. 2015. Responsiveness of the plantar fascia to vibration and/or stretch. J Bodyw Movem Ther. 19:670.
Helmer, K.G., G. Nair, M. Cannella, and P. Grigg. 2006. Water movement in tendon in response to a repeated static tensile load using one-dimensional magnetic resonance imaging. J Biomech Eng 128: 733-741.
Pavan, P.G., A. Stecco, R. Stern, and
C. Stecco. 2014. Painful connections: Densification versus fibrosis of fascia. Curr Pain Headache Rep 18:441.
Pollack, G.H. 2013. The fourth phase of water: Beyond solid, liquid, and vapor. Seattle, WA: Ebner and Sons.
Schleip, R., L. Duerselen, A. Vleeming, I. L. Naylor, F. Lehmann-Horn, A. Zorn, H. Jaeger, and W. Klingler. 2011. Strain hardening of fascia: Static stretching of dense fibrous connective tissues can induce a temporary stiffness increase accompanied by enhanced matrix hydration. J Bodyw Movem Ther 16:94–100.

Sommer, A.P. and D. Zhu. 2008. From microtornadoes to facial rejuvenation: Implication of interfacial water layers. Cryst Growth 8:3889–3892.
Sommer, A.P., D. Zhu, R. P. Franke, and H. J. Fecht. 2011. Biomimetics: Learning from diamonds. J Materials Res 23:3148–3152.
Stecco, C., C. Fede, V. Macchi, A. Porzionato, L. Petrelli, C. Biz, R. Stern, and
R. De Caro. 2018. The fasciacytes: A new cell devoted to fascial gliding regulation. Clin Anat 31:667–676.
Szent-Györgyi, A. 1971. Biology and pathology of water. Perspect Biol Med 14:239.
University of Illinois at Urbana-Champaign. 2008. Water Is ‘Designer Fluid’ That Helps Proteins Change Shape. ScienceDaily: Science Daily Press Release, August 6, 2008. www.sciencedai- ly.com/ releases/2008/08/080806113314.htm. [Accessed 19 April 2021].
Werbner, B., K. Spack, and G. D. O’Connell. 2019. Bovine annulus fibrosus hydration affects rate-dependent failure mechanics in tension. J Bio- mech 89:34–39.Fascia Insights[:]