Mermaid
Plane of Motion
Coronal
Muscle Focus
Spinal Lateral Flexors
External Oblique (same side), Internal Oblique (same side), Quadratus Lumborum (same side), Erector Spinae (same side), Semispinalis (same side), Deep Posterior Spinal Group (same side), Rectus Abdominis (same side), Iliopsoas (same side)
Side bends the spine.

Other Muscles at Play
Anterior & posterior spinal stabilizers provide lumbo-pelvic stabilization and assist with keeping the torso from rounding forward or arching.
Shoulder abductors reach the gesture arm to the side and up.
Scapular upward rotators allow the gesture arm to reach overhead.
Scapular depressors keep the shoulders down away from the ears.
Elbow Flexors turn on the pull on the shin with the hand to help increase range of motion in the side bend.
Objectives
Increase the strength and flexibility of oblique and QL muscles.
Improve flexibility and control of lateral flexors and spine.
Focus on maintaining stability as the torso bends sideways.
Engage the internal support system to maintain stability in the hips.
Anchor through the sit bones while mobilizing the upper body above the pelvis.
Focus on the form of the seated position to stretch the hips muscles.
Focus on breathing to synchronize the movement.