1- Stand straight up with feet apart as shoulder width apart, hold dumbbell in right hand and raise overhead to arm’s length.
2- Lower your dumbbell in a semicircular move behind your head until forearm touches biceps, you can use your other arm to support your shoulder.
3- Then raise arm and return to the starting position, finish repetitions then do the same with the other arm.
Tips and Advises:
1- Make sure that you keep your arm close to head and the upper arm do not move.
2- Keep you body still while performing the exercise.
3- Make the palm facing forward to emphasize the outer head of the tri.