Muscle Group: Biceps
It’s important to understand that your ancillary (supporting) muscles adapt to exercises quickly. We can quickly adapt to movements like Barbell Curls which limit the amount of progress we can make in our biceps. Ancillary muscles are the supporting muscles that assist in particular exercises.
This movement will as Rich Piana put it “confuse” your bodies ability to evenly spread the load which will shock your bi’s into growing.
Pick up a barbell with an underhand grip and hold it shoulder-width apart.
Unlike 99% of bicep curls, you will not be keeping your elbows fixed during this exercise As you curl, allow your elbows to drift forward and finish the curl with the bar in front of your forehead. As you come down during the eccentric part of the movement, allow your elbows to reposition themselves back at the side of your body.