Side plank pose (Vasisthasana in Sanskrit) is an arm balance pose on one arm. This pose has variations for beginners and the advanced full pose that is only suitable for more advanced students.
Side plank pose strengthens the wrists, arms and shoulders and enhances and improves balance. This pose tones the core, including the abdomen and buttocks, as well as the muscles of the arms and legs.
To move into side plank pose, start off in downward facing dog. This pose will be performed balanced on one side of the body and then repeated on the other side. From downward facing dog, begin to shift the weight and turn the feet to the left, so the outer edge of the right foot is on the mat and the left foot is stacked on top of the right foot.
Move the left hand to the hip and turn the body, so it is facing forward and you are balanced on the outer edge of the left foot and the left hand, which should still be on your mat in front of the shoulder, helping to support your weight.
The left arm should be firm and straight with the fingers spread to help with balance. The body should be in a straight angle from the top of the head to the flexed feet on the mat. If you are unable to balance in the pose, you can start out with the feet pressing to the wall to help you keep your balance.
This is the modified pose and you can stay here or take it a bit further, if you are comfortable. beginners should stay here until they have mastered the modified pose. If you want more challenge, you can straighten the right hand and reach toward the ceiling.
The feet will remain on the mat. Advanced students in a hatha yoga class may be taught the full pose when they are ready. This involves taking that right foot that is stacked on top of the left and raising it away from the body toward the ceiling, so the leg is perpendicular to the floor.
To move out of this pose, turn your feet back and lower the right arm back to the mat. Move back into downward facing dog. You will rest and then move to the other side and repeat the asana for a balanced practice.