Extension of a dumbbell from behind the head

Take a dumbbell. Sit on a bench with a backrest and place a dumbbell on your upper thigh. You can also do this exercise while standing. Raise the dumbbell to shoulder level, then straighten your arm, lifting the dumbbell up over your head. The hand should be next to the head, perpendicular to the floor. Relax your other hand or place it on your belt or grasp a fixed surface. Rotate your wrist so that your palm is facing forward and your little finger is pointing towards the ceiling. This will be your starting position. As you inhale, slowly lower the dumbbell behind your head without moving your shoulder. Take a short break at the end of the movement. As you exhale, return to the starting position by extending your arm from behind your head. Hint: when performing the exercise, only the forearm moves, the part of the arm from the shoulder to the elbow remains absolutely motionless. Perform the required number of repetitions and change hands. Variations: instead of a dumbbell, you can use a cable trainer.