Well-known Ashtanga yoga teacher Kino McGregor tells “how she and her students distinguish from the spiritually necessary pain that she seems to be describing in her book, and the pain that indicates injury. She affirmed the difference between acceptable delayed-onset muscular soreness and pain that is to avoided: joint pain, or pain within practice that makes the yogi wince.”
One suggestion on how to navigate this tightrope is the concept of compression vs tension as put forth by Paul Grilley, international purveyor of the Yin Yoga style. He states: “There are two possible limits to range of motion: tension or compression. Tension is a synonym for ‘stretching’, it is the resistance of fascia (ligaments) or muscles. Compression is bone contacting bone or pinching tissue between bones.” Baxter Bell MD, of Yoga for Healthy Aging elaborates further: “Compression really does feel like things (muscles, skin, tendons, ligaments, fascia and bones) are getting smashed together. And sometimes it creates a kind of pinching sensation as well. This pinching sensation is one that I tend to back away from pretty quickly if it shows up in any yoga poses. And because compression could also put collapsing pressure on blood vessels and nerves, if you start to have an unusual pressure sensation in the joint, or start getting numbness and tingling downstream from the compressed area, that is another good indication to release out of the pose a bit.” This concept works fairly well from a specificity perspective: it’s a pretty safe bet to back off if you feel these sensations they’re describing as “compression”.
The problem however: neither of these perspectives is quite sensitive enough. You cannot say with any degree of certainty that just because you’re feeling nothing at all within practice or perceiving what you believe to be a “tension” type sensation that you’re safe in the pose.
Let’s get more specific with this conversation by focusing on one joint in particular: the hip. The hip is one of the most oft requested “focuses” of a yoga class if opened with asking students for what they want to work on. Louise Hay tells us the hip may contain lumps of stubborn anger at our parents. It is commonly discussed as a joint to be “opened” and “accessed” as if a doorway to the divine itself. The past two years have seen an exponential rise in research and discussion about the hip in medical, yoga and public forums. More and more tales of hip injuries are coming to public light: Lady Gaga’s labral tear, Broad’s NYTimes article citing numerous yoga related hip injuries, Diane Bruni's hip injury following a five-year-long regime of hip-opening, and most recently Kino McGregor's hip/hamstring injury.
Before we delve into how far to open or stretch the hips, let's pause to consider some of the myriad of factors to consider that may contribute to various forms of hip pain or injury, whether acutely obvious, or insidious onset repetitive strain in nature.
- Directional morphology of the ball and socket joint (femoral head and neck within the acetabulum) - including hip dysplasia or shallow hip socket; anteversion (forward facing) or retroversion (side (relative backward) facing) of the acetabulum, femoral neck or both; inclination (up or down facing) of the femoral neck and/or acetabulum; this can provide a greater limit to range of motion (hypo mobility or "compression") or a lesser limit (hypermobility or too flexible) in various directions depending on individual specifics (Clohisy 2009, Harris-Hayes 2011, Hunt 2012, Sahrmann 2011, Lewis 2015, Foster 2015, Garner 2015)
- Femoral Acetabular Impingment (FAI) - the femur bumps into the acetabulum sooner due to either or combined: cam (a thicker bump at the edge of the femoral head) or pincer (prominent rim of the acetabular socket) (Dolan 2011, Reiman 2014, Frank 2015)
- The ligamentum teres which extends from the center of the hip socket to the head of the femur is important for hip stability and position sense. Overstretch, partial or full tears can lead to microinstability; hypertrophy from increased strain can make the hip socket more shallow leading to instability. (Cerezal 2010)
- Intactness of the acetabular labrum - a fibrocartilage structure that extends beyond the bony socket, containing few nerves at the edge to convey position or pain information, deepening the socket by 21%, contributing to our position sense of the hip joint, and providing a suctioning seal for the joint to maintain synovial joint fluid distribution and pressure. For such an important structure, it has a poor blood supply for healing on its own (Hunt 2007, Groh 2009, Alzaharani 2014, Dwyer 2014, Nepple 2014, Garner 2015)
- Extensibility of the hip capsule, a thickening of the fascia around the hip joint I often call the "seran wrap covering", also known as a joining of 3 ligaments that run from the pelvis to the femur. The looser the capsule, the less it can offer to stability of the hip joint - this looseness or laxity in the capsule is often biased toward one direction more than the other depending on the person's movement patterns and activity demands
- Soft tissue relative stiffness, relative flexibility - passive resistance from fascia (including the capsule, ligaments, tendons) or from intrinsic passive stiffness of muscle tissue
- Gravity through the body and through the joint - influenced by positional alignment of the whole body (aka posture) and the hip components specifically (Lewis 2010, 2014, 2015). How does that influence soft tissue loading and where force transfers through the articulating surfaces?
- Subtle joint "wobble wobble" - also called hyper mobility or increased accessory motion influenced by many of the above. "Wobble wobble" in the spine and sacroiliac areas can affect the hip via both mechanical and neural pathways and vice versa (Martin 2006, Benjaminse 2009, Hoffman 2011, Sahrmann 2011)
- Muscle imbalance - Subtle movement patterns or subconscious habits, imbalanced recruitment of muscles, muscle weakness, muscles too long or too short to do their job effectively (Casartelli 2011, Sahrmann 2011, Buss 2013)
- Diminished joint position sense or proprioception due to joint variation, injury history, or local or general fatigue (Benjaminse 2009, Cerezal 2010, Alzaharani 2014, Okhravi 2015)
- Altered sensitivity to subtle sensory information as occurs in victims of trauma (Levine 2010, Parker 2015)
- Trunk/core neuromotor control, breathing patterns, foot mechanics, the brain and central nervous system, hormones, nutrition, gut health, collagen makeup, genetics, epigenetics, fatigue, the thin line between zeal for practice and a type-A competitive drive (with yourself or other practitioners), pressure to perform (as is often the case for high profile teachers), psychoemotional/energetic/spiritual factors....and the list goes on and on!!!
So, not only are the factors leading to hip injury complex, but several of them limit your ability to feel your way through it via stopping when you wince or feel compressive type sensations.
In Paul Grilley's itemized response to William Broad's article about women's flexibility in yoga as related to hip injury, his assertion that "pushing through compression is impossible" is misleading. If you consider that compression sensation is bone on bone, I could understand why one might say that. But, consider that when we are talking about extremes of joint range of motion, the places where the bones are coming into contact are not the places they're meant to contact, and may not be as able to resist the attempted "stretching" i.e. compressive force and it is possible to injure bone tissue. And, before you get to the point of bone-on-bone contact, you've at the very least angered if not damaged the smooth slippery articular cartilage that overs the intended points of contact (or articulating surfaces). Even if the points of contact of the femur and acetabulum are not affected, the force will move until it finds a way out - motion occurs where motion is available....the proverbial "something's gotta give". And when it comes to yanking around the hip, that something is often the SI joint, spine, pelvic floor or knees. In the skeletally immature (likely under 20 years old, but I've heard older when it comes to the female hip), putting excessive extreme forces on the skeleton is tricky business. It can and does halt growth and change the way the bones develop.
Remember the hip labrum? When you "compress" the hip, the labrum will be compressed or sheared first because it extends beyond the rim of the socket. You hope it will bounce back, but that is not always the case, especially if you use your femur like a mortar and pestle. Free nerve endings (that transmit mechanical and chemical information about pain and inflammation) and mechanoreceptors (that detect stress, acceleration and tension) within the joint that help tell your brain what's going on in the joint (proprioception, kinesthetic sense) should theoretically send a warning signal. Some of these warning signals are designed to work on a subconscious level as a reflex loop in the spinal cord that triggers an action (or relaxation) beneath our conscious awareness.
I propose that we often ignore the signals that arrive at conscious awareness, but there is a larger issue at play - are we even getting the signals?
When you bring your knee toward your chest (and other variations of deep hip flexion), it might make sense that the femur and socket are coming into contact in the front, at the top of the socket. So, it is often suggested in some lineages to take the top of the thighs back or deepen the groins to make room. If this is accomplished, what is likely happening at the level of the joint is that the femoral head (ball) is traveling to the inferior (lower) portion of the socket and often also posterior (back). The more often you take the joint in this direction, the less resistance the capsule provides, and it starts going there whether you want it to or not....not just while you're practicing yoga. Alzaharani (2014) demonstrated that the pain and pressure sensors in that part of the labrum are less abundant. This means, when the hip goes into that inferior/posterior glide, you may not get a signal at all that the labrum is being "compressed" until it's been damaged, and you're feeling the compression of bone on bone (or the other sequelae of hip labral injury). This direction of glide to excess over-stretches the six deep lateral rotators of the hip (especially quadratus femoris) - limiting their ability to effectively perform their important hip stabilization task, and potentially altering the nerve signaling traveling through the "nerve to quadratus femoris" which provides some of the innervation to the labrum - further dampening the signals! P.s. the imaging sensitivity for posterior labral tears sucks, so a lot of these injuries are flying under the radar.
Kino McGregor has graciously granted me permission to show you a few images of her in yoga poses that stress the posterior/inferior hip capsule and labrum. Although her yoga asana practice has not been implicated as the true underlying cause of her injury, these images illustrate the concept of posterior/inferior glide quite effectively from an external view.
What most yoga practitioners think they're tuning into is the sensation of muscle stretch. The trick is, the more extreme we get into ranges of motion, the less position sense information we get from the muscles. Benjaminse (2009) states "rotations into the limit of joint motion result in progressively smaller length changes in the muscles and in progressively larger tension in the joint capsule. In a sense, the capsule load sensors increase their response as the muscle sensors are losing their ability to detect angular displacement." That's IF the capsule hasn't already been overstretched to the point that it can no longer provide that information when you need it.
So, how do we know how far we should go? I think the more important question is why do we want to go there?
Truly investigating the second question for yourself on your own path of life and practice is the key to unraveling the answer to the first. Unfortunately no one can answer that for you. Not even your guru, your teacher, your coach or your physical therapist. You must get to know your motivations on a deep level, and as we are human they may change from minute to minute.
I think part of that unraveling involves evolving an equanimous sensitivity to not just the gross physical sensations of pain, compression, tension, and joint position, but to the rich sensory experience of the whole that may over time aid our interpretation of what's good, safe and forward progress, and what's potentially hazardous to our wellbeing. This sensitivitity is more challenging when we are fatigued, overloaded, overwhelmed, highly charged, or any imbalanced state of the central or autonomic nervous system. This is often difficult to navigate alone, and working one-on-one with a somatic therapist or trauma-saavy counselor can help tremendously.
Specific to what we discussed in this article, it can be quite helpful to get some outside input on what exactly your joints, muscles, nerves and movement patterns are up to. It takes a special person to help navigate these issues when your movement goals are outside the "norm" of sports medicine. Rather than me making some blanket recommendations on exactly who that should be, why don't you reach out to me? One of my zones of genius is helping people find the right "team", and I'm growing my network every day.
P.S. For those of you reading this who are currently in the weeds trying to figure this stuff out in the midst of an injury, I send love, healing light, and empathy. I've certainly been there myself more times than I'd like to admit :)
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