Inversion vs. Eversion: How’s Your Sole in Side Plank?

A fellow yoga teacher recently emailed me about Vasisthasana (Side Plank Pose) alignment. She asked if turning the sole of your foot down on the bottom leg is healthy alignment or if it could be bad for your ankle. Well, let’s take a look and see!      Man practicing Side Plank Pose (Vashistasana), being careful of foot placement and inversion ankle anatomy

Ankle Sprains

Most of the concern regarding injury here would be spraining the ligaments in your ankle. The good news is that about 90% of ankle sprains happen during ankle inversion (a.k.a. rolling your ankle), but turning the sole of your foot down inside plank is ankle eversion.

Ankle Anatomy

A diagram of ankle anatomy, showing the smaller outside ligaments, which get strained during inversion

If you look at the anatomy of your ankles, it will make sense why this is the case. Turning your ankle in (inversion) pulls on the ligaments on the outside of your ankle. These ligaments are much smaller and easier to sprain than the ligaments on the inside of your ankle.

The most commonly sprained ligament on the outside of your ankle is the relatively small anterior talofibular ligament (ATFL).

Diagram of ankle anatomy, showing the inside ligaments which are stronger

The ligaments on the inside of your ankle, known together as the deltoid ligament, are much broader and sturdier and rarely get sprained. This is the ligament group that gets pulled on when you turn your foot out or when you turn your sole down, as in the above photo of Mr. Iyengar’s Side Plank Pose.


What’s Good for Your Sole

Although I don’t think that it is necessary to put the sole of your Picture of a skeleton in Mountain Pose (Tadasana), aware of inversion anatomyfoot down in Vasisthasana, I don’t believe it is harmful to those who can. There is some possibility to overstretch and cause some ligament instability over time if you are forcing it though.

Overall, the motion or action can help completely engage the side of your body that is facing the mat during Side Plank to act as a supporting arch to hold you up. This is a line of fascia known as the lateral line.

So to answer the question of whether or not to evert, or turn your foot out, in Vasisthasana, just do what feels right in your sole!

Reprinted with permission from Dr. Nolan Lee.

Side Plank Photo:
Ligament Images: Thieme Atlas of Anatomy: General Anatomy and Musculoskeletal System
Lateral Line Image: Anatomy Trains by Thomas Myers

More from Dr. Nolan Lee – check out his series on Yoga Asana for Hip Mobility.

Study with YogaUOnline and Christine Wushke – Fascia Awareness in Yoga & Movement: Keys to Enhancing Soft Tissue Resilience and Releasing Chronic Tension.

Online course with Christine Wushke, called,

YogaUOnline contributor Dr. Nolan LeeDr. Nolan Lee is a yoga teacher and physical rehab specialist in Chicago, IL with an extraordinary passion for understanding how the body moves and functions. Nolan has the unique ability to blend the science of anatomy with the art of yoga. With an active practice at this clinic, Balanced Flow Wellness, he practically applies yoga to restore and maintain health. Dr. Lee also holds a Master of Acupuncture degree and is a NASM certified corrective exercise specialist (CES). He enthusiastically shares his knowledge of yoga and anatomy in lectures, workshops, and on his blog.


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