This exercise is an excellent one for developing triceps, but it is vital that you use the correct technique. Correct body position is especially important.

1 Take a dumbbell in one hand, then place your opposite knee on a bench, together with your other hand, and place your other foot on the floor, flexing it slightly at the knee. Then pull the arm holding the dumbbell straight back and up to your side, making it parallel to the floor - keep your back straight. 

2 Holding the dumbbell so that you have a 90 degree angle at your elbow, exhale slowly and extend your arm as far as it will go, or until your wrist, elbow, and shoulder are in line.

3 Inhale and lower the dumbbell slowly, but only until you reach an angle of 90 degrees at your elbow. Repeat for the required number of reps.

4 Repeat holding the dumbbell in the other hand.