Spread the rope, pump the arms.
Flare the rope outward at the bottom for a deeper triceps contraction.
The rope pushdown isolates the triceps against the constant tension of a cable stack, and the rope attachment is the key detail, spreading the ends apart at the bottom lets you reach a harder lockout than any fixed bar allows. With elbows pinned to your sides, the triceps are the only muscle that can move the weight, making this the cleanest way to chase arm volume without taxing anything else. It slots perfectly after heavy pressing, when your triceps are warm but not finished.
The rope lets your wrists rotate and spread at the bottom, which biases the lateral head and gives a stronger peak contraction. The bar lets you load slightly heavier. Most people keep the rope as their staple and rotate the bar in for variety.
Your elbows are drifting forward and turning the movement into a press. Lock your elbows to your ribs, lighten the stack, and only your forearms should travel.
Lighter than your ego wants. This is an isolation exercise that rewards full range and a hard split of the rope at lockout, if you have to lean your whole body into the stack, the triceps have stopped being the star.
