Complete every rep in a slow and controlled manner and use a light weight until you have properly learned the technique and an appropriate depth.
Lay facing upwards on a flat bench and grasp a dumbbell firmly with one hand.
How to Do:
1. To begin the exercises, lower the weight to a comfortable depth depending on your flexibility. Usually this is around head level (so you are in a straight line). If you feel too much strain during any portion of the movement, stop and lower the weight.
2. Begin pulling the weight back up, raising it above your body in the starting position.
3. Complete all of your repetitions, then repeat this movement with the other arm.