the anatomy of chair pose (utkatasana)


BKS Iyengar introduced the world to the idea of using props to change the anatomy of a yoga pose. He had a deep understanding of which muscles, tendons, bones, and vital organs were involved in every asana he taught. He spent decades studying why pain was caused in one pose, how to deepen a stretch in another pose, and how a yoga block can change everything. Having an understanding of the anatomy of a yoga pose is critical to your ability to properly teach that pose. It also enhances the experience for your students. Name dropping muscles is unnecessary, but being able to pinpoint where pain may be coming from or why a muscle might be tight can have a huge impact on your students – especially if your knowledge of anatomy can give them answers to questions and suggestions for tweaking to pose to make it better for them.

So I have been brushing up on my anatomy. I am working through poses one at a time to gain a deeper understanding of what is going on within the body that makes the pose possible, and what can make the pose seemingly impossible for some students – and how to modify based on that student’s needs.

This book:


is wonderful. It is available on and at Barnes and Noble. It works you through 30 basic poses to begin building foundational knowledge about the anatomy of those poses. The illustrations are easy to follow. It really is a great book.

So the first pose in the book is Chair Pose (Utkatasana).


Lower body:

The knees bend which engages the rectus femoris (the big meaty superficial thigh muscle) and the iliopsoas (a deep hip flexor muscle). Those muscles work to give you that low squat and help you stabilize the pelvis. In the lower leg, the tibialis anterior (the meaty muscle on the front of your shin lateral to your tibia – shin bone) and the gastrocnemius shorten to allow for the flexion in the ankle (keeping the heels on the ground while being the knees). The soleus muscles on the outer edge of the back of the shin lengthen also.




The muscles and tendons which run vertically up and down the spine (the erector spinae and quadratus lumborum) lengthen and allow you to flex and then fixate the spine in extension. The rectus abdominis and transverse abdominis (the huge sheets of muscle we call “abs”) stabilize the torso and help protect the lower back. A slight posterior pelvic tilt engages these abdominal muscles and lengthens the lower back to prevent hyperlordosis (too much concavity in the lower spine) which can lead to injury.



The arms are active in this pose too. The deltoid (the muscle that wraps around the apparent shoulder) fixes the arms overhead. The triceps (at the back of the upper arms) keep the arms straight at the elbows. The trapezius (the diamond shaped superficial sheet of muscle which runs from the neck to the shoulders to the top of the lumbar spine) and rhomboids (a more interior set of muscles – underneath the trapezius – which primarily retract the shoulder blades – scapulae – and move them toward each other) help move the shoulder blades closer together and down the back away from the ears.



Phew, that is a lot. And this pose is fairly basic, anatomically speaking. So how can we modify it?

  • Reducing the bend in the knees and placing the hands at heart’s center instead of overhead can reduce the intensity of the pose if you are still building strength.
  • Positioning the feet slightly apart helps with balance issues (make sure the knees remain parallel).
  • If the spine is too concave, engage the abdominal muscles and tilt the pelvis forward slightly.
  • Seems too easy? Play the game called “how low can you go?” with your bum…and get lower to feel the burn!


  • You could place a block between the thighs and squeeze it while in this pose.
  • You could place a block between the hands and squeeze to further engage the shoulders.
  • You can practice the squat with your back against a wall for more stability.

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