I wonder why these are called glute ham developers we we use them for situps and back extensions. The situps make my hip flexors worn out and the back extensions/hip extensions mostly make my back tired. Seems like the squat rack is the real GHD. And a GHD is more of a "core/hip flexor" developer. CHD?
But maybe that's because mine is a reverse hyper/roman chair and not a true GHD?