Concentration Curls

Grip one dumbbell with your right hand in the center of the handle and sit on the end of a flat bench.

Place the back of your right upper arm against the inner part of your right thigh down near your knee making the forearm perpendicular to the thigh and let your arm hang down straight. With your palm facing directly away from your thigh, curl the dumbbell up until it reaches shoulder level.

Reverse the movement and return to the starting position; repeat with the other arm. The entire motion for each arm should be performed in a smooth, controlled manner that lasts about 3 seconds with the downward movement no faster than the upward.