Place your left knee in the center of a flat exercise bench, with your opposite leg on the floor (your knee should be slightly bent, not locked).

 

Hold a dumbbell in your free hand.

 

Keeping your upper arm pressed close to your side, bend your elbow and bring the dumbbell up toward the side of your chest.

 

Lower the weight slowly to the starting position, and repeat the exercise for the required number of sets and repetitions.