The machine preacher curl isolates the biceps, emphasizing strict form and controlled movement. This exercise targets the lower biceps, promoting muscle growth and definition. The preacher bench supports the arms, preventing the use of momentum and ensuring that the biceps do all the work, leading to more effective and focused muscle engagement.

1. Sit on the preacher curl machine and adjust the seat height.
2. Hold the handles with an underhand grip.
3. Curl the handles towards your shoulders.
4. Slowly lower the handles back to the starting position.