Here is Breathing with side bend from a ‘Dance Anatomy’ book by Jacqui Greene Haas.
1. Begin while seated with legs comfortably crossed in front and hands placed by your sides. Locate your neutral position. Inhale through the nose; lengthen through your spine on exhalation through the nose. Engage the core musculature; gently slide the right hand along the floor and bend laterally directly along your frontal plane. Keep both ischium firmly on the floor. Allow your left arm to lift overhead, maintaining width through the chest. Your head may remain facing the front or may be gently turned toward the direction of the bend.
2.Gently rest the right elbow on the floor, continuing to lift through your center. Do not collapse into the elbow. Hold for a breath cycle, Feel the lower ribs of the left rib cage opening wide as you inhale. Be aware of the difference between the left rib cage’s expansion and the right’s compression.
3. With forced exhalation, feel the left rib cage pulling together and the diaphragm lifting. Engage the deep transversus abdominis and oblique muscles while moving in the longest possible arc. Return back to your seated starting position. Repeat 2 to 4 times each side.