The Half Curl (aka “chest lift prep”/“ab prep”) is a segmental thoracic flexion in supine. You maintain a stable pelvis/ribs, then curl the head/shoulders until the inferior tips of the scapulae are just light on the mat. Range is modest; quality is everything.
Your body's user's manual.
A segmental spinal flexion (and extension on the return) performed supine → seated → forward flexion, then reversing to articulate down. Trains rib–pelvis integration,...