http://taylorcarpenter-pt.com. Taylor Carpenter a personal trainer in Charlotte NC performs a barbell good morning hip hinge. "Good mornings" are a great accessory exercise to improve the deadlift and even more so the squat. Many heavy squats fail due to weakness in the upper and lower back. This exercise teaches you to really focus and drive your upper back hard towards the ceiling to prevent falling forward during hip hinging exercises. Even though squats are generally perceived as a lower body exercise, the tightness and drive in your upper body can make or break the lift.

https://www.youtube.com/watch?v=LTgGTz9votw