Episode 54:
7 Yoga Anatomy Myths Busted

Seven Yoga Anatomy Cues That Shouldn't Be Used Podcast Episode 54 Rough Transcript:

Myth 1: "Tuck your tailbone"
Where it came from. This one seems to come from ballet and dance originally. Dancers are trained to tuck the pelvis or lengthen the spine so they can spin cleanly on a straight axis and to lengthen the visual line of the leg. In an article by Paul Grilley he notes that this cue made its way into yoga because so many yoga and aerobics instructors in the seventies and eighties were former dancers, so they carried the tuck over from their own training without necessarily questioning whether it belonged on every body doing every pose. In another article, Bernie Clark also points out that pelvic tuck cueing doesn't show up in earlier yoga texts, it seems to enter teacher training language later, once that generation of dance-trained teachers was doing the teaching. 
Why it's overused. Let’s look at a couple of studies that dismantle the idea of a single correct tailbone position. A 1996 study published in Physical Therapy measured pelvic tilt and lumbar curve of ninety pain-free adults. They found no meaningful correlation between the two. In other words, you can't reliably predict someone's spinal curve from their pelvic position, so cueing one muscle group doesn't quote-on-quote correct standing posture the way this cue assumes it does.
The second study, from 2011, looked at what a normal, pain free pelvis actually does at rest. And it turns out around eighty five percent of men and seventy five percent of women, naturally sit in some degree of anterior tilt. So it’s not an even split between tucked, neutral, and untucked. So when we cue "tuck," we're usually asking a pelvis that's already sitting forward to move even further from where it naturally rests, and that can flatten the spine's natural curve, limit how the hips actually move, and create unnecessary gripping through the glutes and hip flexors. 
Interesting, according to Cambridge University Hospital, “there is no such thing as perfect posture, and there's no clear evidence that "bad" posture causes pain in the first place”.
What to do instead. The simple answer is to stop treating the tailbone as something that needs correcting. 
On this topic yoga teacher and blogger Jenni Rawlings says that in low-load poses like chair pose, the spine simply isn't at meaningful risk either way, so micromanaging the tilt isn’t really important anyway and makes little difference. 
In his blog, Andrew McGonigle also known as Doctor Yogi, makes the case that tucking and untucking are each situationally useful, tucking to counter an excessive arch, untucking to counter excessive rounding, and that "neutral" itself varies from person to person because pelvic bone shape varies so we should let the pelvis move. He also says ultimately its an unimportant cue, its not going to harm but if we cue anything beneficial it’s that we cue movement. Think slow cat-cow like pelvic tilt movements.

Myth 2: "Stretching lengthens the muscle"
Where it came from. Stretching lengthens the muscle sounds right, which is probably why it's stuck around. You stretch, you get more flexible, so the muscle itself must be getting physically longer? Right? It's baked into a lot of fitness and yoga language so we think its true.
Why it's overused. Let's look at the research. A 2010 paper found that after a single stretching session, or even a few weeks of regular stretching, the increased range of motion you feel is mostly down to changed sensation and stretch tolerance, not the muscle tissue actually getting permanently longer. There is a small, real, mechanical lengthening that happens while you're actually in the stretch, but it's temporary, it's not a lasting structural change.
A 2025 Meta-analysis of sixty five studies and over fifteen hundred adults, found the same pattern. Stretching reduced how stiff the muscle felt but through increased tolerance, especially with repeated sessions, the actual fascicle length doesn’t lengthen, which is the technical term for the physical length of the muscle fibers.
One thing to note here is that long hold stretches are useful for building comfortable range of motion and easing tightness, like those in a yin yoga class. But we shouldn’t stack one right before doing an activity that needs real strength or power from that same muscle because the force output dips for a bit afterward. 
So for any strength practices, we save the long stretches for after rather than before.
And while we’re on the topic of strength training, I love this one because I’ve just started a strength training routine. A 2021 meta-analysis published in Healthcare, which looked at eleven trials, found no meaningful difference between strength training and stretching for improving range of motion. Meaning if your goal is flexibility, strength training and stretching are fairly equivalent paths to achieve that. I’m guessing this is because in either situation you’re actively moving and using your muscles.
What to do instead. Be mindful of the language you use to explain what’s happening in student’s bodies. Rather than perpetuating the belief stretching lengthens a students muscles, which actually we don’t necessarily want to do anyway, explain stretch tolerance and that it’s actually a student’s nervous system easing into allowing you to shift into a deeper range of motion rather than their muscle getting longer. 


Myth 3: "Never let your knees go past your toes"
Where it came from. This one comes out of knee safety research from the nineteen seventies and eighties that has been simplified since then and turned into a blanket rule for every squatting movement, whether that's a barbell squat, malasana, or a low lunge.
Why it's overused. A 2003 study had people squat normally, then squat again with a wooden board forcing their knees to stay behind their toes. Restricting the knees didn't reduce overall joint stress. It just moved it elsewhere in the body.
By restricting the knee, knee torque did drop about 22%, BUT it caused a 10.7x increase in hip torque. The problem with this is our knees are built to be a major load-bearing joint in squat movements, that’s their job. So for some people to achieve safe joint loading, they may actually require the knees to travel slightly past the toes.
A more recent review from 2023 looked at the same question and found the same thing. Restricting knee travel isn't an effective strategy for healthy, trained people. It's really only useful in specific rehab contexts, with light loads and limited depth, for someone recovering from a knee issue, which as yoga teachers we’re not qualified to make these calls unless you’re also a qualified physiotherapist who knows the client's body and injuries and are working with them personally.
What to do instead. For most healthy students, especially in shapes that need real depth like malasana or a deep lunge, forward knee travel is often unavoidable and isn't inherently risky. Every body is different and if something is comfortable for a student, we shouldn’t correct it. For example, someone with shorter femurs relative to their torso is going to have their knees travel further forward in a deep squat no matter what. So you should cue for control and a stable base, something that they find comfortable rather than a fixed vertical line at the toes.
The one thing to note here is that while how far over the toes the knees move is individual to everyone we don’t want to see knees caving inward or bowing outward in any major way as this can lead to injury. The knee should track towards the toes, how far over or behind the toes doesn’t matter as long as they’re in the direction of the toes.

Myth 4: "Shoulders down and back"
I found this one tricky because I feel better if I do it but let’s explore why it’s a myth
Where it came from. From what I could find its been a general posture correction instinct, likely linked to, how common rounded, forward shoulders are from desk work and phone use, so pulling the shoulder blades down and back sounds right as the universal fix and the universal safe position for the shoulder. We don’t want to hunch up our shoulders by our ears, it feels awkward.
Why it's overused. On her blog, Dr. Trish Corley makes a points out that shoulders down and back actually mixes up two completely different movements. Rotation is the shoulder blade turning as the arm lifts overhead. That's what’s supposed to happen. Elevation is the shoulder blade sliding up toward the ears. Which is the actual problem some students have. This typically isn’t a postural failure, it's an overactive upper trapezius, often driven by stress. So when a teacher cues shoulders back to fix elevation, but the student's real issue is restricted rotation, the cue makes things worse, not better.
Just to be clear, this is specifically about load-bearing, arms-overhead shapes, think down dog (Adho Mukha Śvānāsana), or warrior one(Virabhadrasana I) with the arms reaching up. In a resting position like tadasana or savasana, there's no overhead reach happening, so this particular cue issue isn't really in play.
Also a 2019 study by Contemori and colleagues, tested what happens when you force the scapula into a fixed retracted position, the literal shoulders back cue, and found it changes muscle activation patterns and creates imbalances that get in the way of that natural rhythm.
What to do instead. Stop treating shoulders down and back as one instruction. If a student's shoulders are creeping up toward their ears, then that’s what we address. Dr. Corley's suggested cue is simply: “keep your shoulders away from your ears.” 
This cue invites students to find a neutral position naturally with their shoulders away from their ears without forcing depression or retraction, so the shoulder blade is still free to rotate the way it needs to in an overhead position. 
And while I mentioned earlier that this myth doesn’t apply to when arms are down like shoulder blades down and back in savasana or tadasana, elevation can still creep in anywhere, shoulders sneaking up toward the ears is a tension habit, not an overhead-arm problem, so 'keep your shoulders away from your ears' is still a worthwhile cue in many positions. In savasana it's really just a comfort cue at that point, not something tied to this research.

Myth 5: "Activate your core. Pull your belly button to your spine"
Where it came from. This traces back to a specific strand of core stability research and rehab practice from the nineties and early two thousands, built around the idea that, the transversus abdominis, a deep abdominal muscle, needed to switch on first, before anything else, to protect the spine. That idea got simplified into hollowing, pulling the belly in and up, and it spread from physical therapy into Pilates and then into a lot of yoga core cueing.
Why it's overused. This is the myth with the most research behind it. There are actually two layers to why it's a myth that I’ll go over.
The first layer is hollowing versus bracing. Stuart McGill who is a foundational researcher in this area draws a clear distinction between bracing, which activates all three layers of the abdominal wall without pulling in, and hollowing, which is the activate your core by pulling your belly button to spine cue we’ve all heard so many times. Whereas bracing feels like the action when someone is about to poke you in the stomach and you tighten your core. 
So bracing is good. It is more effective at stabilizing the spine. 
However, hollowing narrows the base that supports the spine's structure, and under real load it can actually reduce spinal stability rather than protect it.
However, some people make a further mistake in that they brace too much they brace for all kinds of normal activities throughout the day like tying their shoes even because they’ve heard it helps with support. But this constant, all day clench, creates problems with your diaphragm's function.
Your diaphragm has two jobs happening at the same time. It's the main muscle that moves when you breathe, and it's also a major contributor to something called intra-abdominal pressure, which is its own separate mechanism for stabilizing your spine, on top of the abdominal wall bracing. When someone holds a hard, constant brace, their breath tends to get pushed up into shallow chest breathing, and that restricts how much the diaphragm can actually move, which blunts its contribution to that pressure-based stability. So a rigid brace can end up working against the very muscle that's helping stabilize you.
Since most of you listening will be yoga teachers or atleast practice yoga I doubt I have to go into all the issues that not breathing deeply enough can cause. 
On top of all of this, deliberately hollowing the core can increase spinal compression by 45 percent.
What to do instead. We have two things here and they work together. First, if you're going to cue core engagement at all, cue a gentle overall brace, everything switching on evenly, not a deep pull in, and Cue the brace for the moment it's needed, when someone's actually pressing up or lifting or bearing weight, then let it go. It's not something to keep switched on in the background for an entire class. 
But know that it’s also safe to skip this cue entirely because some people might hear it and based on what they’ve been taught in the past take it to mean a hollow brace which as we’ve discussed puts them in a compromised place. So by cueing core engagement under the guise of making someone safer, we can inadvertently make them more vulnerable. Unless you’re working 1:1 with someone and can more closely monitor what they’re doing managing this may be tricky when you have a full class of 8 or 10 or 20 or even 30 students. 
The second thing you should do is, always remind people to keep the breath moving. Including if they’re in a brace. We don't want to let bracing push someone into holding their breath or breathing shallowly into their chest, because that's when the diaphragm gets locked out of its own stabilizing job. 

Myth 6: "Square your hips" in Warrior I or Warrior II
Where it came from. This one comes out of an alignment focused strands of yoga teaching, the most common is Iyengar but there are others with this focus too where they treats visual symmetry, a squared off pelvis in a lunge or a standing pose, as both the aesthetic ideal and the structurally correct position, regardless of the individual student in front of you.
Why it's overused. People have a massive variation in their bone and joint structures. What is comfortable or right for one person could be agony, painful or simply impossible for another person. The shape someone makes on the outside doesn’t necessarily reflect what their skeletal structure looks like on the inside. I learned this in Paul Grilley’s yoga anatomy course. I’ll put a link to his bone pictures in the show notes if you want to see for yourself. 
This was also shown in a 2016 study published in the Journal of Bone and Joint Surgery, by Chadayammuri and colleagues which looked at people's passive hip range of motion and compared it against their actual bone structure, specifically looking at how the femur is torsioned and how the hip socket itself is angled. They showed that there is a huge amount of variation in how someone's hips move, or don't move and its predicted by their bony anatomy, not their flexibility, the effort they put in or how many years they've been practicing. Some people will never get into a shape because their body simply isn’t designed to.  
What to do instead. So some bodies genuinely cannot square their hips in Warrior I without compensating somewhere else, and as we’ve covered, that's not a flexibility problem to be fixed with more stretching. It's often just their skeleton. Since learning this I’ve been explaining it to my students, especially in certain poses. I teach yin so we don’t have any warriors in class but when it comes to teaching square pose and shoelace pose I always note for them to choose based on what feels right for their hips and what feels right for one person might be different from the next simply because our anatomy is different. There is no right or wrong or more flexible or less. 

Myth 7: "Keep your spine straight"
Where it came from. I think this comes from a broader cultural idea that good posture means a flat, elongated, straight line which has then been reinforced by a lot of yoga marketing imagery of a perfectly upright posture in seated poses.
Why it's overused. A 2021 study published in Frontiers in Bioengineering and Biotechnology, by Müller and colleagues, modeled load through the lumbar spine and found that spinal curvature doesn't make you more or less safe in any simple sense. It changes where the load goes. A straighter spine shifts more compression onto the discs. A more curved spine shifts more force onto the small facet joints at the back of each vertebra. Neither is better. They're just different distributions of the same forces
What to do instead. We cue length and space through the spine without flattening its natural curves. We don’t treat curvature as a flaw to be corrected. It's part of how the spine actually distributes load so let it do its job.
When it comes to spinal health we also want to be mindful of function over form. As Bernie Clark discusses in his book Your Spine, Your Yoga, we’re all different and modern yoga has a tendency to prioritize flexibility and mobility over stability, which is unsafe for many people, especially when discussing the spine so if you teach backbends bear this in mind, understand that each student is different and don’t set up a space where the goal is to bend further because that’s not necessarily the best for their health.

Close
There you have it 7 anatomy myths busted. Ultimately the right movement really depends on the person's body rather than there being one right way to do something. I learned so much in Paul Grilley’s anatomy workshop about how joints and bone structure can vary so much from person to person. So if you look at two people holding an asana and think they look the same, they have the textbook form for this asana, they’re doing it supposedly right but on the inside because of their bone and joint structures, they may be having completely different experiences. 
For me I’ve found the more I’ve learned about anatomy the more relaxed and confident a teacher I’ve become. It’s really been a game changer for me this year.

’d love to know your thoughts. Were any of these a surprise to you? Do you know of more I’ve missed? I’m sure there are a tonne more out there if I find enough I’ll do a follow-up episode. 
If you found this episode helpful, please share it with a fellow teacher friend. It really helps the show get found but also the more these myths are spread and get taken out of the mainstream the safer students and fellow teachers will be when practicing. Thank you listening, have a beautiful week ahead.