The hip hinge which is demonstrated above during a Romanian Deadlift (RDL) is a core movement in the gym. Hip hinging lays the groundwork for olympic lifting, squats, deadlifts, and kettlebell swings. 

The hardest part of learning this is independently moving the hips through flexion and extension while limiting the movement of your spine, namely thoracic over-extension. The main issue I have with coaching up this movement is that most individuals spend their days slouched over in posterior pelvic tilt (think the opposite of arching your low back for a buttfie).

One of the main go-to drills for building spine stability where you aren't moving into flexion or extension during movement is the dead bug. 

Two main points of a dead bug!
1. Neutral Spine while moving.
2. Exhale fully to ensure proper positioning of your ribcage which is keeping neutral spine while extending your limbs.

If you would like a progressive breakdown of how I coach clients from start to the barbell, please leave me a comment and share this with a friend who looks like a question mark anytime they deadlift!