Select suitable weight dumbbells and sit in a preacher bench. The bench should be adjusted to a height that comfortably supports your upper arms and elbows without you needing to arch your back. At this height, your mid-lower chest will touch the back of the preacher bench.
Your feet should be planted firmly and your core is tight. Your arms are outstretched on the pad taking the weight of the dumbbells in a palms up grip. This is the starting position.
Commence the movement by curling the dumbbells up from the elbow joint and squeezing your biceps. The elbows should remain fixed on the bench pad while you exhale through the movement. Do not lift the elbows or use momentum to throw the dumbbells up.
When your biceps are at maximum contraction and the dumbbells approach your shoulders, squeeze for a second and then reverse the movement by extending the arms to the starting position, inhaling as you do.