An isolation exercise for the triceps.
Stand up with your feet shoulder width apart.
Grab the bar with palms down grip. Keep your elbows in.
Holding the bar above your head on extended arms slowly lower the bar in an arc behind your head.
As you exhale, extend your arms above your head.
Inhale and go back to the starting position.
The exercise is dangerous for the elbow joints. Don't use it too much and do not pick a heavy weight.
Do not straighten the elbows completely - always keep them slightly bent.