This is an example of an offensive hook off ball. In this example White 21 is being guarded by Black 34 on the low block with a legal arm bar. As White 21 tries to go baseline he brings his left arm in and under the arm of the defender and lifts the defenders arm. In this play the defender has done nothing illegal and White 21 is responsible for this contact. This should have been an offensive hooking foul on White 21.