HOW: Grab one end of a dumbbell with both hands. Cup the end of it with both hands and press it up above your head. Keeping your elbows in and pointed up, lower the dumbbell behind your head and then press it back up.
FEEL: You should feel your triceps muscle working.
COMPENSATION: Stay standing straight up, don’t lean forwards or backwards. Keep your elbows in, don’t let them come out as you lower the dumbbell.