American Football Rules IFAF Approved Ruling 7-3-8: III

III. A83, a wide receiver 10 yards from the nearest interior lineman, slants toward the middle of the field. Before the ball is thrown, B1, a back, legally blocks him and knocks him down. RULING: Legal unless the block was below the waist (Rule 9-1-6). [Cited by 7-3-8-c-3, 7-3-8-c]