An advanced prone thoracic extension with bilateral knee flexion holding the ankles/shins and a gentle forward–back rocking about the lower ribs/upper abdomen. It integrates spinal extensors + glute–ham synergy + anterior hip length while maintaining quiet ribs/pelvis and a long neck.
The Musculoskeletal System from Head to Toe
The Body's Blueprint
From Beer Barrels to Back Bends: The Unexpected History and Ingenious Design of the Pilates Ladder