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 (or perpendicular) and grasp a dumbbell firmly using both hands, one hand placed over the other.
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 you are using.
2. Begin pulling the weight back up, lifting it straight above your body in the starting position.
3. Repeat this movement as recommended.