Both drills are prone posterior-chain exercises.
They balance flexion-heavy ab blocks, pattern glute–ham synergy, and train scapular organization with a quiet pelvis.
These are core pieces of the Classical Ab Series. They train segmental thoracic flexion and hip dissociation while the trunk stays organized (anti-extension, anti-rotation)....
The Body's Blueprint
A Deep Dive into Extrinsic Muscles and Upper Limb Power