Drags the bar up your body for a brutal biceps peak.

Keep the bar touching your body the whole way, don't swing it out front.
The drag curl rewrites the bar path so it travels straight up your body instead of arcing out front, forcing the elbows back and denying the shoulders any part in the lift. That leaves the biceps alone under tension all the way into a vicious top squeeze. It is the strict variation you reach for when regular curls have become more swing than curl.
Squarely in the biceps, with the strongest burn near the top of the drag. If you feel your front delts or traps, the bar has drifted off your torso or you are shrugging the elbows up instead of back.
Around shoulder-width with an underhand grip works for most people. Going much wider or narrower makes it harder to keep the bar in contact with your body, which is the whole mechanism of the lift.
Not replace, complement. Regular curls let you load heavier through a fuller arc, while drag curls give you a stricter, shoulder-free contraction. Running the drag version second in the session is a classic pairing.




