One arm at a time, total tension, zero imbalance.
Keep your torso still and let only the working arm move.
Curling one arm on a low pulley keeps the biceps under tension from full stretch to full squeeze, because the cable never lets the load fall away the way gravity does at the bottom of a curl. Working one side at a time means your stronger arm cannot quietly take over. It earns its place as an imbalance fixer and a finisher, where constant tension and strict single-arm form matter more than the number on the stack.
Different, not better. The cable keeps tension at the bottom where a dumbbell curl goes slack, so it is excellent for constant-tension work, while dumbbells load the mid-range harder.
You are turning it into a front raise to move more weight. Pin the elbow to your side, drop the stack a pin or two, and let the biceps do all the moving.
Face the low pulley with the working side square to it, standing far enough back that the cable stays taut at the bottom. That keeps the pull line clean through the whole rep.
