What are the back-row attack rules in volleyball?

A back-row player may not complete an attack hit where the ball is entirely above the net if their jump takeoff was at or in front of the 3-meter attack line. Jumping from behind the line and landing in front is legal.

Full Explanation

Per FIVB Rule 13.3.2, a back-row attack fault occurs when a back-row player (those in positions 1, 5, or 6) hits the ball as an attack when: (a) the ball is entirely above the height of the net at contact AND (b) the player took off (jumped) from at or in front of the attack line (3-meter line). The player may jump from behind the line, contact the ball above the net, and land in front of the line -- this is legal because the takeoff was from behind. A back-row player may attack below net height from anywhere. The libero faces a stricter rule: no attack hit above net height from any location (FIVB Rule 19.3.1.3). These rules apply equivalently under USAV, NFHS (Rule 9-4), and NCAA.

Rulesets covered: FIVB/USAV/NFHS/NCAA  |  Rule Reference: FIVB Rule 13.3.2; NFHS Rule 9-4