Bow down to bombproof hamstrings and a strong lower back.
It's a hip hinge not a squat, keep your back flat and let the hamstrings do the work.
The good morning is a hip hinge with the bar on your back instead of in your hands, which makes your hamstrings and back the only things standing between you and folding in half. The hamstrings load up through the stretch as your chest drops, and your back works overtime holding a rigid flat line. Loaded sensibly, it builds the exact strength that keeps deadlifts and squats safe.
Light. This is a long lever hinge with the bar far from your hips, so modest weight creates a big training effect. If you are anywhere near your squat numbers, you are either cutting the range or gambling with your back.
To wherever your deep hamstring stretch kicks in while your back is still flat, often somewhere near torso parallel. The end point is set by your hamstring flexibility, never by forcing your chest lower with a rounding spine.
Same hinge pattern, different bar position. The RDL keeps the load in your hands close to your body, so it is easier to go heavy. The good morning puts the bar on your back, hammering the back muscles harder at lighter weights. Most lifters use RDLs as the main builder and good mornings as the assistance lift.
