Take hold of some suitable weight dumbbells. Plant your feet firmly, knees bent slightly. Your core is tight and your torso straight. Your arms hang down outstretched on the sides of your body, taking the weight of the dumbbells, palms facing each other. This is the starting position.
Commence the movement by curling one dumbbell up from the elbow joint at a time and squeezing your biceps. The elbow should be pinned to your side and work like a hinge while you exhale through the movement. Do not use momentum to throw the dumbbell up. The torso should remain stationary.
When your biceps are at maximum contraction and the bar approaches your upper chest, squeeze for a second and then reverse the movement by extending the arms to the starting position, inhaling as you do.
Repeat on the other side and alternate repetitions in this manner.