Deadlift really is one of those full body compound movements like the squat. If anything there are ultimately more muscles being activated in the deadlift. It's mainly a posterior chain movement/ lower back though. Powerlifters won't train deadlift on back day. That seems to be a bodybuilding thing. We generally Deadlift and then do movements that are associated with it like hamstrings and glutes. i.e.- SLDL's, RDLS, Rack pulls or pin pulls, GHR's, reverse hypers, leg curls.. etc.
Another thing for building a big deadlift, is just practicing the deadlift, and constantly practicing your form and feeling the movement. making small tweaks here and there. You should be at the point where you can be off by just a little bit and you'll know it. Then when you make those muscles that are specific to the deadlift stronger that's also keeping you safer as well. You're essentially building a deadlift machine.
I don't recommend as much for people who are just super strong and can pull a lot, to pull a lot. Some people are naturally very strong and can deadlift more then most people, even more then most people who actually train for it specifically. It's not bad everyonce in a while but it does put you at risk.
If you are a powerlifter and your dedicated to getting better at bench, squat, and deadlift, theres nothing wrong with following a program that has you lifting heavy at certain points. In my programming, I don't pull max effort singles on the deadlift but a few times every 12 weeks and most of the time that's if i'm either peaking for a meet, or just finishing a training cycle in the off season.
I follow the lillibridge method because it just suits my interest in training. It's a 12 week long training cycle. You deadlift heavy every other week. On the weeks you deadlift light, you squat heavy and vice versa. On the light deadlift days its usually around 55-60 percent of your max off a 1-2 in deficit for 3 sets of 5 reps. On the heavy days your just starting 12 weeks out at basically 87 percent for a top set of 5. Each heavy day the percentage goes up and a rep drops. You can also add 5-15 lbs to the number depending on how the last week went. Has you progressively working up to a new one rep max at the end of the 12 weeks. I think something like that is a good way to go about training for the deadlift. There are many many different programs out there though.
Again, if you're not serious about getting better at the deadlift, keep the ego one rep maxes to a minimium. If you're dedicated to improving it, and you follow a proper protocol you can very easily keep yourself safe. It's all in how you go about it.
