Tension or Compression: The Fundamental Distinction

This thread contains an essay that Paul Grilley wrote, at my request, for e-Sutra. The follow-up posts are from myself, senior teachers of The Breathing Project and others. This is still an open thread, and more comments are welcome, including a response from Paul.

Tension or Compression: The Fundamental Distinction
Paul Grilley
September 20, 2004
Ashland, Oregon

Posted to e-Sutra January 4, 2005

Architectural principles start from the premise that all structures, including our bodies, are a balance between stretching forces and crushing forces, or briefly “tension and compression”. The cables that stabilize telephone poles or lift elevators are being stretched, they are subject to tension. The telephone pole itself or the support columns holding up a building are being pressed, they are under compression. When we practice Yoga asana the fundamental distinction to make is this: “Are the physical restrictions I am feeling tension or compression?” Tension is due to the stretching of muscle or connective tissue but compression is determined by the shape of our bones.

Skeletal differences
The bulk of my work as an invited Yoga teacher is anatomical. A few years ago I walked into “The Bone Room” in Berkeley, California and purchased five human femur bones. It was the best investment I ever made. In nearly all my presentations I point out the dramatic differences between these bones. Besides the obvious size and length variations I point out how some bones are twisted 40 degrees backward or rotated 30 degrees upward. These differences might remain a mere curiosity but when these skeletal differences are coupled with the idea of compression it usually turns a student’s yoga world around. Because all of our bones are different, all of our joints compress at different angles of flexion and extension. Through our Yoga practice we can discover where we compress but our Yoga practice will not change where we compress.

A brief outline of the ideas presented in an “Anatomy for Yoga Workshop” is as follows:

1. When we practice asanas we move our joints.
2. When we move our joints our bones pivot away from each other.
3. Because the bones are moving apart tissues are stretched.
4. At first our limits of motion are determined by how much we can stretch.
5. But the ultimate limit to our range of motion is compression.
6. Compression is due to the shape of our bones.

Tensile Metaphors
Virtually all the metaphors of present day Yoga instruction are tensile.
“Relax” – relax the muscle tension, “Breath into it” – soften up the tissue, “Let go” – relax tension, “Make a space” – let the bones move apart. But limiting our conceptions to tensile metaphors is walking with one leg. For the vast majority of us who have practiced yoga for several years the restrictions we experience are compressive, not tensile. It is the inherent shape of our bones that determines what we can or cannot practice safely. And because each person’s bones are differently formed then what is beneficial for one person is destructive to another.

Perfect Postures
My goal in presenting compression as the ultimate limit to a range of motion is to free ourselves from the tyranny of “proper form” and “perfect pose”. Asana practice is supposed to be a mild therapeutic that allows us to influence the movement of prana and fluids through our bodies, but in the present environment there is a naive belief that if we all try hard enough we can “do all the poses”. This is wrong. More damaging then the physical strains caused by pushing to “perfect” a pose is the lingering feeling of inadequacy. Many instructors explicitly or implicitly teach that our inability to perform asanas “correctly” is a reflection of deeper emotional problems. Because of this many students place far, far too much emphasis on “perfecting poses”. Many students pursue this imagined perfection not out of any vain desire to look good but because they earnestly want to uncover whatever is “holding them back” in their spiritual life. Note that “holding back” is a tensile metaphor. Having no idea of compression they dimly imagine that their joints must be restricted by soft tissues that they should be able to “lengthen”, “soften”, or “relax” if they could just “let go” of their emotional baggage.

Teach Skeletal Differences and Compression
Compression is not a native conception to Yoga students. Even if a student senses a “natural limitation” in their movements they will not use the word “compression” to describe it. The closest they will come is “I don’t bend that way.” Time and again I have seen students unable to tilt his pelvis forward in a forward bending posture because the trochanter of their femur is compressed. When I ask them where they feel the restriction they are not sure what to say because they don’t feel a “stretch” in their groin or hamstrings. They are not in pain. Pushing on them doesn’t bother them much. They just “can’t do down”.
Because of the nature of my work I am constantly asked by students what they can do to “improve” different poses. After a quick examination of their skeletal movements I can usually tell them there is nothing to “improve”, their asanas are fine as they are. I tell them that they don’t look like the pictures in the book because of the shape of their bones. People in my workshops usually accept this opinion with a huge sense of relief but this is because they have been introduced to the ideas of skeletal differences and compression. Without these two ideas Yoga students sometimes interpret any suggestion of limitation as “pessimistic”. But if it is possible to communicate to a student that it is the unique shape of her bones that is limiting her then she will start to let go of trying to make her poses “perfect” and begin to relax and enjoy her practice.
I will end this brief introduction with two caveats. One, our mental and emotional life is reflected in the tissues of our bodies but this reflection is primarily in the soft tissues of the body. Two, asana practice influences the health of our bones but this is something different from their general contour. It is the general contour and proportion of our bones that determines our ranges of motion.


Posted March 23, 2005

(LK: Here, finally, are the responses to Paul Grilley’s article about tension and compression. Amy Matthews and Carl Horowitz are senior teachers here at the Breathing Project in New York. Sara Tirner is a New York yoga teacher who has graduated from our Yoga Anatomy program. Matt Huish is an accomplished yogi, teacher and scholar who I had the pleasure of meeting when I taught in Portland last year. His wife Nicole did the cadaver dissection with us last August. My comments are at the bottom of the post.))

From: Amy Matthews
Comments on Paul grilley article for e-Sutra “Tension or Compression: The Fundamental Distinction”

Dear Leslie –

Thanks for asking for my comments on Paul Grilley’s article. It was a pleasure to consider his ideas, and doing so helped me organize my own thinking on some of the issues he raised.

I agree that one way to organize our perceptions in a yoga pose is between the sensation of “tension and compression”, as Paul Grilley points out. The sensation of compression is very different than the sensation of tension (or stretching), and is a rich area for exploration – especially for those who are more flexible. For a student to begin to refine their perceptions to distinguish between these two sensations is a starting point for further refining their experiences.

Rather than having compression be the end point for the exploration of a pose, it can initiate another level of exploration – with consciousness, by changing our alignment we can also change the vector of compression, to flow along the line of force in the bone or to shear off at an angle and create stress at the joints.

In my own teaching, as I’ve shifted my focus from encouraging students to seek the sensation of stretching in muscles to sensing the flow of weight or force through bones I have seen them come to a new understanding of the dynamic relationships between the parts of the body, and how those relationships are affected by breath, attention and intention.

I absolutely support the idea that we should be freed from the “tyranny of “proper form” and “perfect pose”” . . . and I would say that part of finding that freedom is re-defining how we describe limits, and how we describe a perfect pose. Instead of saying that a perfect pose is not achievable, my hope is have students look at what they define as their limits, and see if they can change their understanding of what perfect pose is. With that idea, the understanding of perfection would integrate each individual’s context, and no two ‘perfect poses’ will look alike.

To limit our understanding of the body’s potential movement to a question of flexibility is indeed a disservice to the students and the practice – we can explore the sensation of stretching in the muscles and connective tissue as Grilley points out, develop our sense of compression and lines of force in the bones . . . and we also have the ability to explore consciousness in asana in the nervous system or the endocrine system, in our fluids and tissues, in our senses and perceptions, our reflexive and developmental patterns . . . the possibilities are infinite.

So instead of using compression as the ‘ultimate limit’, we can explore compression as another way of changing what we define as our limits. And rather than looking at flexibility as the ‘ultimate goal’, if consciousness and understanding of the relationships within our bodies is the ultimate goal there is no limit to the depth of our experience in asana.

From: Carl Horowitz

I think this is a nice submission by Paul Grilley and it was quite generous of him to take the time to write this piece for this forum. From my personal perspective, anything that will enable students to understand that they do not have to go any farther, when they have reached their limit, could have very useful applications.

Here are a few simple examples of some ways in which bone on bone compression can occur diagramed in “Anatomy of Movement” by Blandine Calais-Germain on page 183 and 188.

My feeling is that the following are some very insightful statements:

“My goal in presenting compression as the ultimate limit to a range of motion is to free ourselves from the tyranny of “proper form” and “perfect pose”…More damaging then the physical strains caused by pushing to “perfect” a pose is the lingering feeling of inadequacy. Many instructors explicitly or implicitly teach that our inability to perform asanas “correctly” is a reflection of deeper emotional problems.”

The kind of flawed thinking that Paul is trying to help uncover is well worth examining. And if this concept of compression being the “ultimate limit” to range of motion can help free people from this kind of deluded thinking, I am all for his use of the concept. Hopefully it can help people understand that they do not have to continue pushing themselves (note: the term pushing, as Mr. Grilley used it in the above quote, is a compression metaphor) :o) to go any farther.

I also understand that in the context of this forum it is not possible to give a complete or exhaustive analysis of anything and I am sure Mr. Grilley understands that often a joint reaches end range of motion for reasons other than bone on bone compression and frequently has to do with the purpose and function of the joint and the way the joint capsule has formed for a person over his/her lifetime.

I will use the joints in the fingers to give a simple example of what I am talking about. If you push your fingers (the distal and proximal interphalangeal joints and metacarpophalangeal joints) into extension (the opposite of making a fist) they will reach end range and it has absolutely nothing to do with bone on bone compression even though it may feel to some like compression. But it is still end range and going farther could cause serious damage to your fingers.

Often end range of motion is end range of motion and there is no reason to try and change it regardless of why or how a person has gotten to end range. By practicing in a way that is right for you things that are supposed to change will change over time and things that should not be pushed against will change in ways that a practitioner might not consciously realize are necessary. So if your practice is about going farther and you start realizing that by practicing in this way you are actually becoming less open and are not able to go as far, it is an indication that your body is trying to tell you something and I would say that this would be well worth listening to.

I would also say that looking at the body from the perspective of tension and compression in end range of motion could cause people to stay within a concept of farther being deeper and more “advanced”. However, farther often does not mean deeper and more advanced often has nothing to do with either farther or deeper. There are a limitless number of directions for one’s awareness to evolve and grow towards and I would say that more awareness ultimately might be a more useful equation for more advanced than further or deeper. Awareness of internal sound during practice, the flow of the breath inside the body, feeling the circulatory system and how it affects the fluidity of the muscular and skeletal systems, the effect of any technique on the energetic or emotional systems, the effect of practice on the intellectual system and the personality are just a few examples of a small number of different directions that more awareness could be directed. In reality the options are limitless.

This being said, I feel fairly strongly that any information that will help people practice more safely and intelligently, whether anatomically accurate or not, can be useful and beneficial.

Thank you, Paul for this thoughtful submission.



From: Matt Huish

Comments on Paul Grilley Yoga Anatomy Video

I have finished watching the Paul Grilley anatomy video and have a few comments. Paul, both in the article and in the video, uses tension and compression as his “mantra” but ends up focusing almost exclusively on the nature of compression in yoga. Tension and the role of muscular/fascial limitation is sorely neglected. A student who was interested in learning about the complex topic of anatomy and how it relates to yoga would get a very one sided and limited view from this video.

Let me make it clear that I do think that bony compression has its place in the limitation of the range of motion within asana. However I think that Paul completely overstates its place in the context of yoga practice. It was apparent even from just looking at many of the students that there was still tensile factors present, muscular/fascial limitation of the neck, arms, shoulders, etc. Even Paul himself demonstrating the pronation of the forearm obviously seemed limited by an overdeveloped muscle mass of the forearm. Taking these factors into consideration, some of the students would find a still greater range before encountering the bony compression. I have seen many students like these in the hundreds of students I have worked with and I have watched their range of motions increase vastly with healthy proper practice. To say that “these are the bodies they are born with” and leave it at that seems somewhat fatalistic and limiting to one’s practice.

I was also a bit concerned with Paul’s assessment of the hyperflexible folks. He seemed to be saying that there is really no hyperflexibility and that it is ok to overbend in the elbow and shoulder region. The basic implication of this is that it is ok to keep stretching stretching stretching until you hit bony compression. This ignores the balance of strengthening in yoga. Too many folks today are already under the assumption that yoga is just about stretching the body. Muscular integrity comes about even more through a proper balancing act between opposing muscle groups and the act of strengthening areas that are weak. Hypermobile people oftentimes have incredible weakness in these same areas. Also, muscles acting across a joint that is angled beyond 180 degrees are going to have to work harder and run a greater risk of injury.

Beyond these basic points I was also disappointed in the fact that there was not a very good introduction to the fundamental concepts of anatomy that would be useful to the yoga student. Some of the examples were very poor. For example, when he asked the students to raise the arms in flexion, it was obvious that the shoulder blade was involved in the mobile student even as he claimed it wasn’t. Another thing I found disturbing was the assessment that one of the students couldn’t squat due to bony compression in the ankle. Squatting ability is not just due to the angle of the ankle. There are other factors involved such as abdominal and shin strength. The example of “neck” bending in the dvd ignores the complex nature of that region with its many vertebrae, different ranges of motion through each of these joints (the neck is not one joint), and the muscular/fascial bindings on this area. Just looking at these students it was obvious that certain tensions were held in this region.

One last point. I think that sometimes it is really the muscular/fascial bindings that cause the compression in the first place and it is these factors that need to be worked with. While compressive factors may have a say in a particular student, I have sure not seen it near as much as the tensile factors in the many students I have worked with.


From: Sara Tirner

I don’t fully understand what he means by compression. Is it when bone hits bone, no matter what we do, we can go no further? And by the shape of the bones and how they fit together, this may be significantly different for each individual? If that is true, than what he says seems to make sense. (We probably all experience this in one place or another in our bodies.) With me, it is at the location of the ankle. I am fairly convinced it is this relationship that prevents me from more deeply bending my knees and therefore limiting my ability to jump, never was a good jumper in ballet class! But self diagnosis can be grossly inaccurate! Perhaps just something that sounds like a credible excuse. However, this anatomical relationship also prevents me from taking the warrior 1 position as defined in the Iyengar tradition. If I try to do that position, the limitations in the ankle result in a nasty compression in the lower back, no place – else for it to go, it has to give somewhere! As a result, the Viniyoga alignment ((LK: shorter, wider base)) works so much better for me, try to tell the folks that think I’m wimping out! Instead, I was practicing ahimsa.

I appreciate that he (Grilley) is trying to recognize differences in the individual and encourage them not to try to achieve some predetermined ideal, but is it really true that all limitations are based solely on the shape of the bone? I also am no anatomy expert. It would be great to get an MD that specializes in bone and soft tissue to comment. Perhaps an orthopedic type. ((LK: Actually, our own Carl Horowitz does a good job in his post, above.))

From: Leslie Kaminoff

Paul Grilley makes a very important distinction in discussing the concepts of compression and tension in the context of recognizing anatomical differences. His advice to asana practitioners to ask themselves: “Are the physical restrictions I am feeling tension or compression?” is sound. Whether we are teachers or students, learning about the unique shape and proportions of individual skeletal systems is a very important step towards making the practice of asana safe and effective. For anyone who wants to go deeply into this material, I can recommend Paul’s video as a good introduction.

However, even in the limited context of asana practice, I don’t consider “Tension or Compression” to be “The FUNDAMENTAL Distinction.” Paul’s phrasing of his topic is part of the problem, because it implies that the distinction to made is between tension AND compression, and if we can sort out which of the two are responsible for our physical sensations/restrictions, we will know what we’re dealing with.

In reality (and gravity), we are ALWAYS dealing with a COMBINATION of tension and compression forces. What we experience at any given moment is a result of how and where we focus our attention. In fact a valid definition of asana practice is: “getting the tension and compression forces in our bodies into a state of balance.” When we are neither obsessed with tearing through our limits nor bashing into our boundaries, we can unlock the natural forces of intrinsic equilibrium that nature has built into these remarkable bodies. That many of us learn this lesson only after going too far in one or both of those directions is unfortunate. Paul’s teachings can be an important step towards greater understanding and less self-inflicted suffering.

My point is, calling something like tension/compression *fundamental* to Yoga needs to be done in context. In fact, if you removed all reference to yoga or asana from Paul Grilley’s video, it could just as easily apply to stretching, gymnastics, dance or martial arts. This does not in any way invalidate the truth of what he’s saying, it just means that I think any discussion of asana needs to connect with the greater universal principles of Yoga, such as Sthirasukhamasanam (YS 2:46) and Tapasvadhyayaishvarapranidhanani kriyayogah (YS 2:1).

In this context, I see Paul’s information as a valuable lesson in Ishvara Pranidhana: accepting with an attitude of surrender the things you cannot change or control — like the bony limitations of your skeletal system. Having accepted the reality of those boundaries, we are free to pursue change in the areas that are actually capable of changing (tapas). An introspective process of self-study (swadhyaya) allows us to distinguish one from the other.

In the interest of full disclosure, I feel obliged to reveal that I am signing a contract to write a new book about Yoga Anatomy. Some of the points I have just briefly made involve key concepts that I will cover in the book, so I apologize if some of my comments seem a bit cryptic. For a full explanation of my view, you are of course encouraged buy the book when it comes out next year ; ).

Comments (1)

Hi. I own Paul’s anatomy dvd and I really enjoyed it. I’m by no means an anatomy expert, but I understand basicly what he was presenting in the dvd. I only wish he could of explained better in some fashion how students can “recognize” when one is either experiencing tension or compression in asanas. I know it’s just a dvd, and there’s only so much you can cover when creating one. But I wish in some way he could of shown viewers’ how to distinguish between the two. Randy–>

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