Markus Henning Giess interviewed Germany's leading fascia researcher Dr. Robert Schleip (Ulm University) during a Fascia Seminar in Germany in summer 2014.
M: How does fascia react to long held stretches (three, five or ten minutes) without muscle tension (e.g. yin yoga)? What happens after getting out of the pose to the form, structure, fluid, remodelling of the fascia and the felting? Could you choose one aspect and talk about it in more depth?
R: The most concrete evidence I can offer in that respect is the study of Helene M. Langevin or Sarah M. Corey. They tested ten minute moderate stretches on rats, although we don't know if the rats were relaxed. With these tests they could show that long held moderate stretches had an anti-inflammatory effect.
Now it would be interesting to find out if it works the same way in humans.
But the result in itself is highly interesting – I didn't know that before and I would love to know if a long held stretch could have a lasting viscoelastic deformation effect on the tissue.
Viscoelastic is not elastic. A rubber band is elastic. You can stretch a rubber band as long as you want and it will always return to it’s original position. Collagenous connective tissue, which we call fascia, is not like a rubber band and more like a gummi snake lollie, like gelatine. Gelatine is cooked collagen and that is viscoelastic. In a training which targets viscoelastic tissue, the amount of time in traction plays a large role.
If I have a gelatine snake, and that’s how we can imagine some of our fascia tissue, such as tendons, it is important how slow and how long we hold or pull on the tissue. That is the viscoelastic creep. If I hold a pose for a long time it has a sustainable effect. If I pull for just a short moment you won't have an affect on the viscoelastic material.
You could say, that if you pull on a gummi snake with the same force for some time, it will yield more and more to the stretch. If you pull for 10 minutes, then it will require an even longer time for it to recover or perhaps it may never recover and will stay longer then it’s original state.
That is what I wish for myself sometimes with my hamstrings. (laughs)
So the slowness and the length of time in the pose are important factors for viscoelastic deformation.
(Note: Yin Yoga Practitioners) The downside for you is that long held stretches have an adverse reaction on the sensor motor skills of your body. If I come out of a long held stretch, I need some movement before my fine motor skills return. After pressing out a „sponge“ for 10 minutes the blood flow is less then before.
After 10 minutes you may want to come out of the pose, walk a couple of steps to allow fresh lymph, fresh blood and fresh oxygen to return to the tissues and then continue. This would be an example if you wanted to work on an adhesion in the tissue.
This would be a good compromise.
On the one hand side, the longer the stretch, the stronger the lasting effect will be in regards to a mechanical deformation, but on the other hand the nervous system will be temporarily numbed.
M: Is the numbed nervous system and the lack of fine motor skills that we may feel coming out of a long held passive stretches, what we in yin yoga describe as emotions of fragility or uncertainty?
R: Yes, that could be a good explanation.
M: That would explain why some people with back issues feel as if their backs may break as they come out of a long held yin yoga pose. That feeling usually lasts for about 2-3 minutes before it dissolves.
R: Yes, if you move a little after the stretch, it feels all right.
But if you would test these people on how high they could jump or how precise their movements are after a long held stretch, you would discover, that they are quite clumsy. They slowly inhibit their reflexes with long held traction.
M: Do we reach the joints with long held stretches? You said that tendons only stretch up to 4%. How much do ligaments or capsules stretch?
R: If it is a tight ligament e.g. ligamentum iliofemorale (one of the ligaments of the hip joint), the stretch is only very minimal.
(Note: The ligamentum iliofemorale – can withstand forces of up to 350kg)
M: Should we then call it rather stimulation then stretching and more importantly do we actually get to the ligaments?
R: Yes, with passive stretching, without muscle tension. The ligament will go into tension and then the question is, how far can one go. 1-5% might be possible until the ligament will tear, which we, of course do not want.
Before you tear a ligament there is a micro tearing zone and it is still speculatatory, if you can reach this zone through yoga asana practice.
M: Is it true that the myofascial tissue (muscle & fascia) consists of more elastin then collagen fibres and therefore it is more elastic then ligaments? Does the myofascial tissue stretch with the muscle or is it only the channel for the muscle, to allow the muscle to slide?
R: The tissues ability to stretch or be flexibility is not relative to its elastin content. This is very often misunderstood. Elastin fibres are not like a rubber band.
The rubber band like spring effect (of collagen fibres) functions similarly to how a bed spring stores energy – no matter how long or how intensely I pull on it, it will not increase in length. This is what physicists call elasticity. When I release the tension, it immediately returns to it’s original state like a bow (bow and arrow). Rather then losing strength when pulled for minutes at a time, it stores the energy.
What a physicist calls elasticity is not the elastin, it is the collagen. If you pull a bow string you might temporarily deform the bow, but you won’t lengthen the string itself. If you let go of the bow string, the bow will return to its original form. This is collagen in work.
Elastin is like chewing gum. You can pull an elastin fibre much further then a rubber band.
If you meant the stretch of the chewing gum, then you are right. The tissues with more elastin fibres have a higher capacity to stretch. You can stretch elastin 150% before it tears. With collagen it would be only 10-12%.
Collagen serves better to store energy – elastin serves better to stretch.
With the sheath of the muscles, the structure is more important then the ability to stretch. The architecture of the sheath is grid-like similar to the structure of a pair of stockings. The stockings itself are not as stretchable as you would think, but because of the grid-like structure it appears to have a huge ability to stretch, like the sheath of our muscles.
The question is: How can we take care of this fascia network in yoga or in every day life with daily stretching, so we can restore the multidirectional orientation if we have lost it. (Note: After felting of the tissue or when the tissue gets stuck together).
M: So the approach would be to stretch in many different directions, meaning multidirectional?
R: Right! Maybe we should (and I get a headache just thinking about it) go to the gym to train the muscles in a short range regularly to stretch the surrounding fascia when pumping up the muscles. That would mean that fascia training is not only bouncing movements, melting stretches, slow deep tissue massage, but weight lifting as well.
M: If fascia can contract and the lumbar fascia has pain receptors, could a contraction in the lumbar fascia lead to back pain?
R: Yes it could!
M: Can stress trigger contraction in the fascia and therefore pain?
R: The answer on the "can" question is yes.
M: If we would have to give a recommendation to people for general health and prevention in an holistic sense, could you say A: a good active muscular and cardio training B: a good passive training with long held stretches (e.g. yinyYoga) and C: a healthy mental state (e.g. through meditation)
R: The question is clearly answered if you formulate it so well. :-)
You cannot substitute the active stress on the tissues through meditation.
And if you only do melting stretches, that is wonderful for the intramuscular fascia, but if the long stretched muscle is only relaxed while stretching you do not reach the tendons.
We should stretch like cats in the living room, when they do their beautiful melting stretches and dig their claws into the new and very expensive leather couch and then pull in a long held stretch.
This would be the active resistance stretches (Note: Muscular tension to create resistance during a stretch as in an eccentric stretch) which we are already aware of because there is the possibility of 1% stretching in the tendon. The tendon, which connects to the claw, needs the pull back from the muscle.
(Note: There is a power or load transition on the tendon by shortening the stretched muscle).
We need active muscle stress, to nurture our fascial net. We also need passive muscle stretching.
M: Is it correct that when the body is under stress or has too little movement it builds up too much tissue leading to matting of the tissues or adhesions?
R: There are commonalities and differences.
If overstressed, the tissue may felt (mat) too, but inflammation will be present, at least at the beginning. Later, wherever you find felted tissue, the inflamation will be gone, but the felted tissue will continue to grow and grow.
M: Can you explain to a yogi what felting is?
R: That is the big question!
We, the research team at the University Ulm created this term for an undirected collagen fibre or growth.
Healthy collagen fibres have a healthy directional collagen, either parallel or grid like. If you have a scar, or you have overstressed the tissue or you are immobilised, the tissue felts.
If you put a joint in plaster and take the plaster off after a couple of weeks, the fascia in this area will be weaker and felted. That means that the fibres are not directed anymore.
M: Will the tissue be thinner in some areas?
R: No, if you immobilize completely, than the tissue grows like a spider web.
M: Do you know if a „sour body“, meaning an acidic diet rather then an alkaline diet influences the fascia?
R: Yes, we know it from the myofibroblasts, that the ph-value is essential for it. Not in the blood, nor in the urine, but in the matrix, in the connective tissue and this is hard to measure.
But it is known through cell culture experiments, that the ph-value has a great influence.
There are indications that an „acidic ph-value“ leads to increasing contractions in the myofibroblasts. That would mean that e.g. the myofibroblasts would react more aggressive, a wound would close faster and there would be more scar tissue.
M: So one could say that consuming toxic substances like alcohol, nicotine and foods with a high acidic ph-value, would have an affect on contractile tissue?
R: It could have an affect and is very likely.
In yoga, you work on the mechanical environment and we do it with fascial stretches or a manual therapist works from the outside in. Here we speak from a mechanical stimulation, to direct the fibroblast to build a different structure in the body.
But the biomechanic environment as a whole is just as important!
Also through some evidence there is another speculation, that the biomechanic environment, which the medicine and pharmacology sees as the silver bullet, to change the behaviour or performance of the body, only has a limited effect on the fibroblasts.
The fibroblasts are still stem cell alike primordial cells. They can build and dismantle and seem rather to react more on mechanical stimulation then chemical stimulation.
In this respect it would mean that somebody who is practicing yoga might be more successful than somebody who only tries to treat and regulate the fascia through their diet.
M: Thank you so much Robert for the interview.
For more information on fascia and Robert Schleip go to: www.somatics.de