Preacher curls are an excellent exercise to target and thoroughly exhaust your biceps. They are a good exercise to do towards the end, after the more basic movements. The movement is also similar to the concentration curl as the upper arm is immobilised in both exercise.
Position
You will need a preacher bench in order to do the preacher curl. The bench has a pad agaisnt which you lean your upper arms and leave your hands hanging below. So grab a bar and sit at the bench with your upper arms against the pad.
Alternatively, if your gym doesn’t have a preacher bench, it’s not the end of the exercise. You can adapt by using the back rest of a bench. However, as the bench is likely to be narrow, you won’t have space to work two arms at a time and will have to use a dumbell instead. Personally I prefer the use of the backrest and dumbell as I can adjust the angle of the back rest and work one arm at a time.
The angle of the upper arm rest
The whole effectiveness of the exercise depends on the angle of the preacher pad. Too often, the pad is not vertical enough. This means that as the rep is over as soon as you reach the vertical since beyond this, gravity is helping you. The result is that your range of motion is narrower.
The optimum angle for your upper arms is to be slightly beyond vertical so that you can curl your lower arms all the way to the vertical position. If your upper arms are vertical, then your lower arms won’t be able to reach the vertical – you can’t fold your forearms over your upper arms! in this case again, your range of motion would be less.
This is why I prefer doing the preacher curl using the backrest of a bench – I can set the angle exactly to what I need, not to what a manufacturer decides is best for me.
Execution
Sitting at the preacher bench or standing behind the backrest of a conventional bench with your free arm gripping the backrest for stability, breathe in and then exhale as your curl the bar or dumbell up. Lower the weight all the way down for a full range of motion and to complete the rep. Try not to move your body to much. In effect ,the preacher curl is a much more strict variation of the concentration curl as you are less able to cheat by leaning back with your body.
One arm advantage
Working one arm at a time, the free arm can help towards the end of the set. If you had a spotter, the spotter won’t know exactly how much help you need. Whereas if your free arm is helping the working arm, you know exactly how much help to give to just go past the sticking point. You also have the advantage of having a more natural motion – your arm will not be directly facing in front but will be slightly inwards.
It’s hard to get this exercise wrong – as long as you get the pad angle right and go through the full range of motion, you can be sure your biceps will get a hell of a workout.