Execution:
1
Set the preacher bench so your arms rest on the pad, armpits against the edge.
2
Flex your elbows to curl the H-bar toward your shoulders.
3
Squeeze the biceps at the top.
4
Lower under control, don't fully extend to keep tension.
Tip: fully locking out on a preacher can stress the biceps tendon — stop just short of full extension.