Set-up: Begin by sitting on a mat with knees bent.
Movement: Engaging your abdominals and entire core, lift your heels off the floor. From the side a 'V' shape will form between your upper legs and torso. Rotating through the middle and upper back, turn your torso to the side. Hold for prescribed time, return to the center and repeat in the other direction. Maintain an active contraction in your abs and ensure core stability for the entire duration of the exercise.
Emphasis: Do not use momentum or swing through the exercise. Use minimal rotation in the lower back. Your arms may be extended further from your body to increase the difficulty.
Repetitions: Once rotation to both the left and right sides is complete, this counts as one repetition.