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.
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...