Stand straight with your feet shoulder width apart, holding the dumbbells by your sides with your palms facing forwards.

Start by bending your elbow and bring the weight up until your hands are approximately level with the shoulders. Then slowly extend the elbow back down to just before the starting position to keep constant tension. Your hands should remain roughly in line with your shoulders on the way up and down. Keep your wrists aligned with your forearms and your elbows should remain fixed to your sides throughout the movement. Repeat for the desired amount of repetitions.

Avoid using momentum from the body to bring the weight up or dropping on the way down without control.