Q. But don’t I need to “do cardio” to stengthen my heart?

Actually, no, you don’t. You need to move more, and not at intense levels. Let me explain. Of all the wonderful, amazing things our bodies do, the most critical, the most imperative is to regenerate cells. 50-70 billion cells (which make up our tissues, which make up or organs, which make up our bodily systems, which make up us) die each day in the average adult human. Your body has the capacity to replace all of these cells. In fact, your life depends on you regenerating these cells. The recipe for cell regeneration is quite simple:

  • 1 part electricity (to move your cells)
  • 1 part blood (to feed your cells)
  • 1 part lymph (to remove cellular waste)

Mix together. Grow cells.

In baking, you can get all the ingredients right, but if you mix it wrong, you may end up with a culinary disaster. The same with  cellular regeneration. Mixing it correctly means moving all of your skeletal muscles as often as you can throughout your day. A combination of stretching, squatting, pulling/pushing your body weight with your arms, and walking comes closest to moving every skeletal muscle.  It is through muscle movement that blood is pulled from our arteries into our smallest of vessels bringing it to our cells (aka tissue food) and facilitating nerve health and cellular waste removal (you have to take out the garbage, bruh!).

So back to the heart. If cellular regeneration is our biological imperative, then you could consider your body a cell-making factory. Your heart and all 600+ skeletal muscles are its workers. If you are sedentary much of your day – sitting for breakfast, sitting for your drive to work, sitting at work, sitting for lunch, sitting for your drive home from work, sitting at dinner, and sitting in front of the TV/computer/book in the evening, and the only time you really get moving is for 30-45 minutes of intense cardio at the gym, you are relying on one worker, your heart, to pump hard enough to get blood to all of your cells in a very brief window of time. Wouldn’t it be more cost efficient for your heart to calmly pump blood into your arteries and the other 600 plus workers, your skeletal muscles, to get the blood into your tiny capillaries and hence your cells? If you are running a cell making factory, would you rather have one worker for 30-45 minutes or 600 workers all day long?

Q. Ok, so I’m moving all day long, don’t I still need to get my heart rate up?

Actually, no. Your heart gets plenty strong pumping blood all day long. When you push towards your maximum heart rate, it’s the stress equivalent of being chased by a bear. When your heart goes from a calm, steady rhythm to fast & furious, your body automatically secretes stress hormones and goes through all its fight or flight reactions. This is not good, as many of us already are plagued with constantly high levels of stress hormones.  No matter how much cardio you do, it will never be enough to effectively pump your blood into the tiniest of vessels. You need muscle movement to do this. And you need it all over. And you need it all day. And you can even get more of it at night, if you sleep on the floor.

Q. Uh, how exactly does one move all day long?

  • Walk every day – one long walk or multiple short walks; walk errands that you would otherwise drive.
  • Transition to a standing work station. See my favorite movements for my standing work station.
  • Take a 2 minute movement break every 30 minutes
  • Get a squatting platform for your toilet
  • Install a pull-up bar and hang from it daily; work towards being able to pull yourself up
  • Go to your neighborhood park and play on the children’s play structure. Seriously. Go. Now.
  • Garden with hand tools – shovel & hoe instead of a rototiller; manual push mower instead of gas-powered; clippers instead of a weed eater; watering can instead of a sprinkler.
  • Every choice you make throughout your day, which will be almost every choice you make, ask yourself how can you do it with more movement?

Get moving, there are cells to be made!

Namaste, Michele

In reply to a dead but long living king

I received quite a few comments, on my personal Facebook page, to my article on headstand. Below are my clarifying responses. While I don’t include the original comments from my FB friends, they are fairly obvious within the context of my replies.

Reply to W.

Fan or not, Hector’s study is hugely important to biomechanics literature as it relates to yoga and to yoga literature as it relates to mechanical considerations of asana. There is very little out there that looks at the mechanics of yoga postures and their mechanical consequences. Hector was not trying to prove that loading the neck was bad. She set out to determine how much load is happening, rate of loading, center of pressure, and neck angle; contextualize these findings within what we already know about spine mechanics (lots); and apply this to an increasingly popular and controversial yoga posture. It’s through this extrapolation that one might conclude (me in this case) that unnaturally loading the neck is not good and that sirsasana provides the type of loading known to cause chronic and acute injuries.

You make a great point about loading of the neck not being limited to compressive forces. There are indeed tensile forces loading our cervical spine via our musculature. Buried within the 100+ pages of Hector’s thesis, she references studies that look at the minimal forces shown to cause cervical failure. These force studies, in humans, must be done in cadavers for obvious reasons. So, to account for the activity of surrounding musculature that would be found in a living person, cadavers’ skeletons were anatomically restrained in order to simulate the stabilizing properties of neck musculature. What they found, surprisingly I assume, is that larger fractures and forces were generated. This indicates that muscular stability or restraint may not increase tolerance for higher loads. Other researchers found that age, gender, disease, endocrine function, congenital factors and arthritis all affect tolerance values for cervical failure. Coincidentally, she does discuss African wood bearers, who are practiced at carrying large loads on their heads. In one small study, 90% of male wood bearers exhibited cervical degeneration compared to 23% of the control group. Elimination of natural cervical lordosis was seen, which puts the spine into pre-flexion – a known condition for cervical failure under axial loading. In other studies, females carrying large loads of wood had more prolapsed discs, herniations, and listhesis than those with moderate loads.

Ethically, a clinical study that seeks to prove that neck injuries are caused by certain loads can’t and won’t be performed on living humans, so we have to rely on research studies with cadavers or retrospective studies like those with wood bearers – which may be the closest thing we have to proving cervical loads do indeed cause injuries. When I put all of this together – case studies,  biomechanical studies, anthropological studies with wood carriers, clinical studies  done on glaucoma & blood pressure, and all the anecdotal studies from yoga teachers and practitioners, the evidence is clear, if not overwhelming, that supporting more than 8% of your body weight on your neck is dumb. Even if you do strengthen your cervical bones and other tissues by loading, I can’t imagine you strengthen it over five fold. But, again, the studies have not been done, which is why Hector’s study is so important.

Reply to M.

Iyengar taught, in his books anyway, that the full weight of your body should be on your head in sirsasana. Fortunately, many good teachers, like you, instruct students to place little to no weight on their heads. This better protects the neck, but then you have to consider that most people have meager compressive and tensile loading histories in their shoulders and arms, outside of some planks and possibly pull-ups in the gym/studio. I suspect that loads produced in the shoulders & arms from headstand or handstand far exceed most peoples’ loading histories and capacities. Nobody has studied this that I’m aware of.

The context of fear and empowerment is so important to this discussion. In my early 20’s, I was diagnosed with panic disorder, which was layered on top of a history of generalized anxiety. At age 26, I began rock climbing and that was the beginning of the end of my battle with anxiety. Climbing for me was terrifying, but I persevered (main motivator being I was totally in love with the guy who was taking me climbing:) and through overcoming my fears of heights, hanging belays, run outs, and dynos, I overcame my fear of life. Climbing is inherently dangerous, but 99% of the danger can be mitigated by good choices. What I’m learning about headstand (and shoulder stand) is that even the best choices (alignment, good instruction, acquiring strength, etc.) may not protect you from accumulated damage from putting 50% or more of your body’s weight onto your cervical spine, unless you are levitating your head, which I suspect most people aren’t. Listening to your body and doing what is right for you, while in most cases is sound advice, may not override the truth of biomechanics when it comes to standing on your head.

Reply to J.

I applaud you for recognizing your “youth” as a teacher and putting your student’s before your ego. I wish I had showed the same restraint. It took me a while before I realized that just because I can do a headstand, arm balance, etc., it doesn’t mean I have the maturity in my practice to teach it. And, for what is now paramount to me, it does not mean that I understand their impact on biomechanics well enough to be teaching them to students, whose movement and loading histories I don’t know well. I’m not sure, though, if “feeling good” is always a good marker for the safety of a posture like sirsasana. Much of what I’ve read in the case studies and in the personal stories of long term yoga practitioners discusses cervical spine injuries as more chronic or cumulative in nature – not of the burst fracture type – but of accumulated damage from unnatural loading on insidiously degenerating discs and bone density-compromised vertebra. Most of these practitioners “felt good” for those years they were doing sirsasana, until they didn’t.

Reply to H.

You are right; the Hector study did not look at duration in headstand as a risk factor for cervical injury. However, earlier studies of headstand related to glaucoma found that duration positively correlates to increased intraocular pressure. I would posit that greater duration would be associated with fatigue, thus disrupting ecological balance between arm/shoulder forces and head forces. Your advice to students not to kick their legs up in sirsasana, and to work on having the strength to weight ratio to lift them in a controlled, symmetrical manner, certainly aligns with Hector’s study. As for shoulder stand…. it is another posture that has not fared well in the medical literature…more to come.

Reply to a different M

Hector’s study showed repeated loading of the head and neck due to intrinsic bouncing and weight shifts between the arms and head. Unless you were completely levitating your head from the ground (were you?), it seems like you would be unable to completely remove loading forces from your neck. I  would love to hear your technique.

Reply to R**

I edited my post to say the following: “I’ve been in many yoga classes, where headstand was cued, but few of them came with warnings about headstand’s potential effects on glaucoma, detached retina’s, neck issues, or uncontrolled blood pressure.” I appreciate the feedback that helps me to clarify what I really mean.

** R is a former teacher of mine and has reached the Intermediate Junior I level in her Iyengar teacher training, which is frankly badass in the exquisitely rigorous training curriculum and testing process that is Iyengar (don’t let “intermediate” and “junior” fool you, this is a remarkable accomplishment). Originally, I said that I had never had a teacher give contraindications for glaucoma, when instructing sirsasana. R challenged me on this. I have taken classes/workshops from a handful or formally trained Iyengar teachers but it has been some years and I don’t recall these contraindications, but I don’t trust my memory either. However, in recent memory, in local and regional studios in the last year or so, I can remember specific times when the warning was not given, because I was listening for it. That is a more fair statement.

General reply to all

I wrote this article from a teacher’s perspective. But as a student/practitioner, I have a different relationship with the King. Ironically, I used sirsasana as a therapeutic exercise (protocol of Loren Fishman that I referenced in my article) after I tore my labrum from the bone and partially tore my supraspinatus showing off  in downward dog. I credit sirsasana with my near miraculous, almost full recovery.

Namaste, Michele

The King is dead. Long live the king.

The so-called King of all asanas aka salamba sirsasana aka supported headstand is one of the crowning achievements in yogasana. If you can perform headstand, you join an elite group of yogis. If you teach it, especially to a group of wide-eyed beginners, you are a yoga rock Goddess. Another teacher once bragged to me that, within some period of time (months? a year? I can’t recall), every student in her class was able to perform sirsasana. I taught it at one time too. Before I had any business teaching it. I continued to teach it after I considered myself qualified. What qualified me? The usual stuff – I regularly practiced it. I read and watched tutorials on the internet and in books. I learned from other teachers. I took a couple of workshops.  I taught headstand because I craved the status. I desired to impress. I delighted in being responsible and lauded for another person’s accomplishment. I never wanted to hurt anyone. I’d like to say that I didn’t hurt anyone. But I don’t know. There were no reports of injuries. But, then again, I’ve had students confide in me about injuries sustained in another yoga class, including one suffered from prep work and attempts at headstand, but these students never told the other teachers.

But here’s the thing. I thought that if I followed the cumulative wisdom of alignment in headstand that I, and anyone I taught, would be safe from injury. I thought that if I drilled the shoulder girdle prep work into my students ad nasueam (lift your shoulders! lift your shoulders! lift your shoulders!) and dampened my enthusiasm and that of my students by  patience, restraint, and slow, methodical prep work, it would be all good. I was wrong. I liken this King of all yoga poses to King Henry VIII, known for many things, but most notoriously for lopping off tens of thousands of heads during his reign. Nobody knows how many heads have been lopped off by King Sirsasana, because nobody is counting. OK, nobody has literally lost her head with this pose, but we do know that adverse events can and do occur with headstand and that they can be of a serious, life altering nature.

Here is what’s been written up  over the years in case reports in the medical literature and captured in a 2013 review article entitled Adverse Events Associated with Yoga: A Systematic Review of Published Case Reports and Case Series. Keep in mind that this is not an inventory or accounting of the actual number of adverse events caused by yoga. These are the very few cases, where someone experienced an injury or other adverse event directly attributable to yoga; and where that person was seen by a physician, who subsequently wrote about the event and published the case in a scientific journal. What is missing from the number of cases reviewed (76) are the potentially millions of injuries/adverse events that occur each year in the US alone, where over 15 million people practice yoga and pranayama regularly. There is currently no way of knowing how many of these events occur each year because studies large enough to provide a valid estimation have not been done. In the above review of cases, headstand was culprit in 10 of the 76 cases.

Adverse events attributable to headstand included:

  • Worsening of vision secondary to glaucoma; this 46 yo female yogi fully recovered in several months by avoiding sirsasana
  • Progressive pigmentary purpura – a rusty brown skin patch caused by leaky capillaries (tiny blood vessels) of the forehead; the treatment was topical corticosteroids and the clinical outcome for this 59 yo male was unclear
  • Bilateral orbital varices (bulging veins in the eyes) due to increased blood flow;  treatment and clinical outcome were unclear for this 62 yo female
  • Basilar artery occlusion aka a stroke; the 34 yo female yogi received inpatient treatment and physical therapy  and had not fully recovered one year later
  • Progressive optic neuropathy (nerve damage to the eye) secondary to glaucoma; the course of treatment and clinical outcome for this 46 yo female were unclear
  • Bilateral conjunctival varix thromboses or enlarged veins with blood clots in the eyes; the 60 yo male yogi had a surgical excision of the blood clots but the clinical outcome was unclear
  • Progressive optic neuropathy (nerve damage in the eye) secondary to congenital glaucoma; the treatment and clinical outcome for this 47 yo female yogi was unclear
  • Early glaucomatous optic disk change and visual field loss aka pathological changes in the eye accompanied by worsening vision; treatment for this 29 yo male yogi was avoiding inversions, which stabilized his eye status
  • central retinal vein occlusion aka eye stroke; this 55 yo male yogi underwent eye surgery, but did not recover

If I had glaucoma or a family history of glaucoma and a yoga teacher cued headstand without detailing why it would be contraindicated for someone with glaucoma, I would walk run, possibly screaming, from the room because at the very least,  teachers should know this universally agreed upon contraindication. I cringe to say it, but I’ve been in many yoga classes, where headstand was cued, but few of them came with warnings about headstand’s potential effects on glaucoma, detached retina’s, neck issues, or uncontrolled blood pressure. And then, confounding matters and tarnishing the shine I feel when I call my teaching style “Iyengar-influenced,” there is this, from B.K.S. Iyengar from his seminal work, Light on Yoga: “I have taught this pose to a lady of 65 who was suffering from glaucoma. Now she finds the eyes are completely rested and the pain in them is much lessened. Medical examination revealed that the tension in the eyeballs had decreased. I am mentioning this to prove the value of the correct head stand.” One could not be faulted in believing that a good teacher can align the bad away in sirsasana, even though numerous case studies, as well as full research studies, show that intraocular pressure rises in headstand and exacerbates glaucoma.

While I have a macabre fascination with headstand-induced strokes and vision loss, my real interest lies in the biomechanics of sirsasana and potential or actual musculoskeletal injuries to the cervical spine.The weight of an average adult head is 7.5% of total body mass. Your cervical spine was designed to carry the weight of your head, or about 7.5% of your total weight. In headstand, as you will learn later, you ask your neck to bear upwards of 50% of your body’s mass. For example, I weigh 125 lbs, so my head weighs about 9 lbs. Thus, my neck has a loading history of hauling around 9 lbs give or take a hat. However, when I perform headstand, I potentially place more than 60 lbs of weight onto my cervical spine, which, again, has a loading history and capacity of 9 lbs or less. Vertebra are made of trabecular bone, which is the spongy variety and more prone to fracture. Loading beyond tolerance levels subjects your neck to the possibility of a burst fracture. Burst, in case you need reminding of its definition means “to break suddenly and violently apart, spilling the contents, typically as a result of an impact or internal pressure.” Not something you want associated with your neck. But a more likely scenario, detailed below, is the possibility of spinal cord compression by a compromised cervical spine.

What I found remarkable about these cases was that none is the type of musculoskeletal injury you might expect to find when you  hold the majority of your body weight on the fragile vertebrae of your neck. To an emergency room physician or orthopedic doctor seeing a headstand-related neck injury, it’s going to be a no-brainer. A neck injury, where you might expect one, is neither as fascinating nor case-worthy as, say, a pneumothorax (collapsed lung) caused by Kapalabhati or breath of fire. So, I went searching and found a few case studies that were not included in the 2013 review article. In one case, a 63 yo woman, who had practiced yoga for 30 years and had a daily headstand practice, presented with bilateral hand numbness. Imaging showed severe multilevel degenerative disc disease, spinal stenosis (narrowing of the spinal canal in which the spinal cord runs), and secondary compressive myelopathy with myelomalacia  aka compression of the spinal cord by the vertebrae. In another case, a 63 yo man presented with history of tingling & numbness in his finger and toes, weakness and stiffness in all four limbs, and frequency and urgency of urination. There was no history of trauma to his neck or back. For 25 years prior, he had done headstand daily. He, too, was found to have cervical compression of his spinal cord. While case studies are captivating, they don’t tell us that much. What I needed was a research study. What I found, was even better. I uncovered a Master’s Thesis completed in May 2012 by Rachel E. Hector from the University of Texas, Austin, entitled Sirsasana (Headstand) Technique Alters Head/Neck Loading: Considerations for Safety. I could not have dreamed of a better find.

Here is how the study played out. Three groups of 15 yogis practiced one of three variations of sirsasana. Variations occurred in the entry and exit  from the postures, while the actual holding of the headstand was the same for each group. Group 1 entered and exited sirsasana by lifting/kicking one leg up at a time; Group two bent both knees, then straightened them together; Group 3 extended both legs and lifted symmetrically, in a pike position. I present a sketch of the entry techniques from Hector’s thesis.

Three ways to enter/exit headstand

Three ways to enter/exit headstand

Participants performed their respective variations, holding for 5 breaths, while a force plate beneath them measured peak forces acting on the head and neck, loading rate of those forces, center of pressure, and neck angle in the frontal plane at C3 (cervical vertebra 3). The study study examined the weight-bearing responsibility of the head and neck – separate from the arms, which I found to be a critical parameter. You can read Hector’s thesis to learn how they rigged the force plate to eliminate interference by arm forces.

Highlights of the study revealed:

  • the average yogi loads the head with 30-50% of his or her body weight while performing headstand
  • Individuals entering the posture with legs extended and together (pike position) exhibited the lowest maximum and average forces during entry with over 75% of participants using this technique staying below the threshold of vertical loading known to cause cervical failure (image on far right)
  • Individuals entering the posture by lifting/kicking one leg at a time experienced the greatest forces on the neck, with more than one half of them experiencing forces above the loading threshold for potential cervical failure (image on far left)

If headstand is responsible for an unknown number of strokes, vision loss, and debilitating damage to the cervical spine, why is still practiced and taught in most yoga studios? I think the reasons can be complex and beyond my ability to articulate nuances of empowerment, sacrifice, injury, and redemption in yoga. The courageous, thoughtful, and frankly brilliant Matthew Remski, the most compelling writer on philosophical aspects of yoga injuries, explores these ideas in his heady WAWADIA Project . I can not recommend it enough. I’ll go further, you should pre-order a copy of his soon-to-be-published-but-not-soon-enough book (which was crowd-funded, no less), because it’s first printing will sell out.

While Matthew wades through the deep stuff, I’ll pluck the low hanging fruit and merely bullet a list of popular, but mostly unexamined, “medical” benefits of King Sirsasana, tidily summed up in this giddy, optimistic article 10 Awesome Medical Benefits of Headstand. Fortunately, there are practitioners out there like Dr. Kathleen Summers, another yogi doc, who writes in a fairly balanced three-part post about the purported benefits of sirsasana and some potential dangers,  addressing several of these claims.While some of them are reasonable and may be valid, most are unexamined. My comments are in brackets.

The 10 [so called] Medical Benefits of Headstand

  1. Relieves stress [possibly for some; for others, it will likely increase stress hormone secretion]
  2. Increases focus [definitely]
  3. Increases blood flow to the eyes [yeah, that thing about glaucoma]
  4. Increases blood flow to the head & scalp [uh, no; the body has a highly regulated, secure system that will not throw the brain under bus for folly or whim]
  5. Strengthens shoulders and arms [yes and yes; in fact, Dr. Loren Fishman, a world-renowned rehabilitation physician and long time yoga practitioner and teacher, in a small pilot study (10 participants), produced remarkable results using sirsasana and even sirsasana prep work to heal torn rotator cuffs.]
  6. Improves digestion [huh? what? digestion is a downward action; human physiology is designed to push food, urine, feces, menstrual blood, and babies down and out; this makes about as much sense as having a delivering mother stand on her head to improve the birthing process. Ugh.]
  7. Helps flush out the adrenal glands [really? please elaborate]
  8. Decreases fluid build up in the legs, ankles & feet [yes, it will increase venous blood return, but only while you are in the pose]
  9. Develops strength in the core muscles [yes; this is more likely with a controlled pike variation of entry and exit; but while stabilized in headstand, the same alignment applies as in Tadasana – neutral pelvis and ribs to bring the core musculature to its appropriate length for maximum force generation]
  10. Stimulates the lymphatic system [yes, but a better, safer way to stimulate your entire lymphatic system is whole body movement such as walking in alignment.]

When these master-blessed messages are perpetuated in books, magazines, videos, websites, and by a staggering number of teachers in countless studios, then you have potentially hundreds of thousands of people clamoring to honor the King, without a clue that sirsasana can be a very nasty ruler indeed. While it is possible to suffer a musculoskeletal injury in just about any yoga pose, the stakes for musculoskeletal AND other adverse events like stroke and vision loss are higher than most would be willing to wager – if only they knew.

So, I end by circling back around to the work of Rachel Hector (who, by the way, recently published her findings in the Journal of Bodywork and Movement Therapies) and leave you with my recommendations, based on her work, for practicing sirsasana – IF you still feel compelled to practice it. But first, let me be very clear about some contraindications and caveats.

Contraindications:

  • If you have glaucoma or uncontrolled blood pressure, do not practice sirsasana
  • If you have low bone density in your spine, do not practice sirsasana
  • If you have degenerative discs in your spine, do not practice sirsasana
  • If you suspect that sirsasana is injuring you, do not practice sirsasana
  • If you feel pressured by teachers, students, media, or your own ego to practice sirsasana, do not practice sirsasana
  • If you are 35 of older (the age range with the highest risk for disc degeneration), do not practice sirsasana, and if you do, do not practice it daily. While Hector’s study did not find age to be a factor (her study subjects ranged in age from 18-60), intervertebral immobility and disc degeneration come with aging. Large, repeated, asymmetrical loading onto immobile, degenerative cervical discs that are not designed to withstand 50% of your body weight can, as the cases studies highlighted earlier, cause cervical failure resulting in neurological damage to the spinal cord. This damage is cumulative. You may not know its happening until one day, you know it’s happened.

Caveats:

  • According to Hector’s study, the taller you are and the more you weigh, greater are the loading forces and loading rate applied to your neck
  • Men tend to have higher loading rates and maximum forces on the cervical vertebrae (largely explained by their greater weight), however, studies on male cadavers have consistently shown that males have a much greater loading capacity before cervical failure occurs. Are you one of the lucky ones?
  • The subjects in Hector’s study ranged in yoga and headstanding experience from 6 months to 20 years and that experience was not a predictor of any outcomes. It bears repeating: headstanding experience was not a predictor of any outcomes. Experienced headstanders, with as much as 20 years experience, had no added protection from negative cervical spine outcomes. This was the most surprising result of the study and possibly the most important to the yoga community. There is a perception that if you get hurt in yoga, it is your fault, that you were novice, or not practicing good alignment, or you weren’t ready for the asana you were attempting. Matthew Remski, once again, illuminates these perceptions brilliantly in a piece on headstand that inspired me to begin consideration of its risks. The darker side of this coin is that if you are experienced and in good alignment, you might think you won’t get hurt. But in reality, being experienced at headstand may not protect you and being inexperienced may not put you at greater risk for injury. I can’t quite wrap my headstand head around this, but it bears consideration.

Recommendations for practicing Sirsasana:

  • Enter with legs extended (no bend in knees) and lift, symmetrically, in a controlled manner. This method of entry measured the least amount of forces to the neck and occurrences of sudden changes in loading, as it loads the head and neck slower than the other methods. This method of entry requires more intense upper body activation and controlled loading – essentially a better strength to weight ratio that kicking one leg up at a time.
B.K.S. Iyengar in Sirsasana

B.K.S. Iyengar entering sirsasana

  • Exit the pose quickly, by allowing one leg to drop to the mat in a controlled manner. This method of exit, as opposed to the pike exit, appears to reduce over-flexion of the cervical spine upon exit. Flexion-compression, also called pre-flexion or axial loading, loads the cervical spine without is natural curve and is the most vulnerable configuration of spinal alignment, which can result in spinal injury due to buckling failure.

The king is dead. Long live the king.

Namaste, Michele