Last time I did them was back in 2008, thereabouts. I was one of those guys who insisted "I eat a lot," you all know the type, so it wouldn't matter what I did it wouldn't have caused me to get any bigger. So I can neither credit nor discredit their effectiveness from personal experience. I like the idea of being able to spot yourself and do negatives on each arm, so that seems like a pretty good reason to do them.