Extend legs out at a 45-degree angle, bending right knee and pressing the inner edge of right foot against inside of left knee.
Lift head and shoulders off the floor. Keeping abdominal engaged, gently ‘rock’ to the right, balancing on right hip, using the right arm and your abs to help stop the movement. Return to center. Repeat 10 times to the right, and then do 10 reps to the left.
Reference: Shape Magazine