Supersets and giant sets work well for inducing metabolic stress, especially those that stress the muscle at different lengths.
Here's a skull crusher variation where I lower the bar to my nose for 10 reps, then to my forehead for 10 reps, then behind the head for 10 reps. Try it!
Sure all the pros are roided out to their mutant gills. That doesn't mean we can't still learn some incredibly valuable back-training tips by observing how the big bastards train.