I think my analogy was completely lost on you. I didn’t say the lift was like a sit up. I was comparing the useful hinge volume and the useful sit up volume between two different scenarios. I think that is a valid observation considering you started out by saying a better way to do good mornings is to do a less effective version that significantly cuts the effective hinge volume.
So you can use more weight than a traditional good morning…but then you’re just doing a regular good morning anyway? Why let the continental good morning be limited by your regular good morning weight? Actually, if you’re going to just do a regular good morning in the end, why not just do them to build the posterior chain and skip bouncing a heavy bar on your spine? Definitely “hits” the back (literally), but for hypertrophy it’s like expecting your arms to grow a lot from hitting a punching bag (so that this one lands, that’s another analogy).
I think the phrase that more accurately describes what’s going on is “lots of partials” at best.
If you’re not “loose,” do a warm up set with lighter weights before the working sets and microload your working sets up as you progress to avoid injuries.
Being pumped means almost nothing as far as being able to do a set with better form. Bouncing and rolling a bar on your spine doesn’t seem like the best way to warm up and prepare your spine for heavy hinging but to each their own I guess.