Swimming is a prone contralateral extension drill: alternating arm/leg lifts that train thoracic extension, posterior oblique sling (lat ↔ glute), and breathing under rhythmic load, while the pelvis stays heavy and the neck stays long.
The Essential Language of Movement, Anatomy, and Exercise
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)....