Anatomical Breakdown Of Side Plank

Side plank is a challenging posture. It combines aspects of both strength and flexibility. But, as with many difficult poses, its difficulty can be just what makes it fun and empowering. In this article, I’ll break down the anatomy of side plank. We’ll take a closer look at what’s happening in this posture and how to work with it in a safe way.

Aspects of side plank

In Sanskrit, side plank is called vasistasana. In Vedic mythology, Vasistha was a sage. You could consider that this pose embodies the strength and grace of a great sage. But, as with many poses that appear at first glance to be all about strength, side plank actually requires a certain balance in strength and flexibility to do it with ease.

There are variations of side plank that increase the amount of both strength and flexibility required. But, let’s start with the anatomy of the basic side plank. In the most basic version, the hand or forearm and the foot of the bottom side of the body are on the floor. Those are your connections to the ground. Your body is stacked sideways over those connections. The most basic version of side plank is as if you were standing in anatomical position, then abducted one arm, and then someone tipped you sideways to balance on that abducted arm. Ideally, your body is in a single plane, with your torso and pelvis neither in front of nor behind your shoulder girdle.

Anatomy of side plank

The shoulder girdle

The shoulder girdle is an important source of support in this pose. Your lower arm is abducted to about 90 degrees, so the deltoids are engaged as are supraspinatus, and your upper trapezius. An engaged serratus anterior is especially important in the armpit to maintain the stability of the shoulder girdle so that you can bear weight in that arm. Latissimus also contributes to the strength of that arm and shoulder base.

The abdominals

While the focus in the posture is often on the arm and shoulder girdle, side plank is really a whole-body pose. All of the abdominal muscles are engaged to stabilize the spine, but especially the internal and external oblique muscles and the transverse abdominis. The erector spinae muscles will also be engaged subtly, in balance with the abdominal muscles, to help stabilize the spine.

The hip muscles

Finally, we need some engagement from our lateral hip muscles to stabilize our pelvis and keep our hips up in the air. The lateral gluteals, gluteus medius and minimus, contract to keep our hips from dropping toward the floor. The lateral gluteals on the lower side of the hip are working to prevent adduction on that side. There is also likely to be some amount of engagement of the adductors of the top leg to prevent too much abduction from the top hip.

Techniques

There is both a strong grounding and lifting intention in this pose. In a posture like side plank, the qualitative intentions that you work with can often help you find your way into the pose as much as specifically thinking about engaging this or relaxing that. That said, the technique for setting up this pose starts with establishing your base. Connect your hand or forearm to your mat and press into it with intention from the armpit. The action of pressing into the floor firmly will help engage serratus anterior and create a stable base for your shoulder girdle.

Once you’ve established your base with the shoulders, set your lower body in place and engage those lateral gluteals to stabilize your hips. Work to connect the action of pressing into the floor with lifting the hips into the air. See if you can feel the relationship between grounding and lifting. If the basic version of the pose is stable and comfortable, then you can explore more advanced variations. For example, in the Ashtanga tradition, the version of vasistasana that we do includes grabbing the big toe of the top leg with the top hand and lifting that leg up toward the ceiling. Another variation could include creating a half lotus with or without a bind with the top leg and arm.

Cautions

There are some cautions to keep in mind if you’re exploring vasistasana. One of the most important parts of doing this pose safely is to keep the shoulder in a neutral position in the joint and use the big muscles to support it. This is so that you’re not over-using the little rotator cuff muscles.

If you’re new to weight-bearing through the arms and shoulders, start small and build strength slowly. Start with other two-handed weight-bearing postures and build the strength to hold poses like plank before experimenting with one-handed weight-bearing poses. And if something feels “off” or painful in your shoulder in side plank, come out of the pose. Try to set up the pose again. If it doesn’t change, then consider whether you would benefit from more preparation work in other upper body weight-bearing poses before revisiting vasistasana.