Bell on your back, hinge hard for the posterior chain.
Bend at the hips, not the spine, keep your back flat the whole way.
Pinning a kettlebell against your upper back and hinging turns your torso into a long lever, which loads the hamstrings hard in their stretched position as your hips travel back. Your back muscles work isometrically to hold the flat spine, and the glutes fire to snap the hips forward at the top. It is a smart way to groove the hinge pattern and build posterior chain strength when all you have is one bell.
Hold it with both hands against your upper back or the base of your neck, elbows pointing down. Keep it pulled in tight, if it drifts off your back it will yank you forward mid hinge.
Both are hip hinges for the hamstrings, but the good morning puts the load high on your back, which makes the lever longer and every kilo feel heavier. The RDL holds the weight in your hands, so it allows more load while the good morning rewards strict positions with less weight.
Hinge until your torso is near parallel to the floor or until your hamstrings run out of stretch, whichever comes first. The moment your lower back starts to round, you have gone past your range.
