The preacher curl depends on a preacher bench (or some other stable, angled surface) you can use to support your upper arms. By using the pad to change your upper arm angle relative to your torso, you're giving your muscle a different type of stimulus than the standing biceps curl. Build Your Arms With These Preacher Curl VariationsCheck out these variations to add the preacher curl to your training plan. That should be a move you can maximally load, like a barbell biceps curl. As we've noted, both free weight and machine variations of the preacher curl will offer slightly different experiences.