These are bad to the bone once you figure out how to do them. Set up the "stops" so you can enjoy this dead-stop variation.
The main point is to pull the bar into your abs – just a shade above the bellybutton – by driving the elbows up. Don't pull the bar up with the arms – drive with your elbows.
As with any row, keep your back flat and tight and wear a belt. Watch the video, especially the last set in the drop set, and see how my body position is fixed and I'm just driving with my elbows.
I'll have to admit that my mind was elsewhere. We were all sitting in the lounge at the Los Angeles Strength Seminar and everyone was drinking wonderful things like beer and bourbon, often together. One lovely young woman was drinking a wine spritzer. I can allow that, if you're a lovely young woman.