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.
A prone thoracic extension drill with coordinated arm and leg abduction/adduction (“open/close”) performed at a small hover. Trains posterior chain endurance, scapular organization, hip...
The Master Architects of Movement, Heat, and Hidden Strength