If you want big traps, the type that makes you hearing impaired, then heavy deadlifts alone aren't going to cut it. And neither will twitchy, ultra-heavy shrugs that make you look like you're doing a chicken dance.
You need time under tension. Dumbbell shrugs with a 3-5 second hold at the top are money. Contract the traps as hard as possible at the top of the shrug. Do 4 sets of 10-12 reps.
Do the math. A set of 10 shrugs with a 4 second hold at the top of each rep will last 50-60 seconds when you add up the hold time and the lifting/lowering time. Do your shrug sets last about a minute each? Or do you stand there and twitch with your way-too-heavy dumbbells for 20 seconds?
Look, the shrug doesn't have a very long range of motion. So people who shrug too heavy don't spend enough time putting the traps under a significant amount of tension. When you hold the top in that 3-5 second range...
- You have to lighten the load quite a bit.
- You extend the time under tension and you can distribute more tension onto the traps.
- You actually build traps.