What does the ITF rulebook consider to be "the service motion"?

Question

According to Rule 18b of the ITF Rulebook:

During the service motion, the server shall not... touch the baseline or the court with either foot.

What, exactly, constitutes "the service motion"? I had always taken that to mean "the motions leading up to, and including, when you actually hit the ball." However, what if you step into the court as the result of some kind of continuous movement that you started prior to hitting the ball? For example, the rules permit the server to have one or both feet of the ground; if you jump to hit the serve and then "land" inside the court after hitting the ball, is that a foot fault?

Does hitting the ball automatically "end" the service motion?

Answer 1

Rules 16 and 17 of the ITF Rulebook.

16. THE SERVICE Immediately before starting the service motion, the server shall stand at rest with both feet behind (i.e. further from the net than) the baseline and within the imaginary extensions of the centre mark and the sideline. The server shall then release the ball by hand in any direction and hit the ball with the racket before the ball hits the ground. The service motion is completed at the moment that the player’s racket hits or misses the ball. A player who is able to use only one arm may use the racket for the release of the ball.

17. FOOT FAULT During the service motion, the server shall not: a. Change position by walking or running, although slight movements of the feet are permitted; or b. Touch the baseline or the court with either foot; or c. Touch the area outside the imaginary extension of the sideline with either foot; or d. Touch the imaginary extension of the centre mark with either foot. If the server breaks this rule it is a “Foot Fault”.

If, for whatever reason your foot touches the baseline before hitting/missing the attempt to hit the ball, it is as a foot fault. The moment you hit the ball, however, the service motion is considered complete and landing one or both feet on the baseline is still a legal motion.

Foot faults are usually called if the player jumps for the serve from the baseline, so as long as you jump from behind the baseline, it won't matter if you land on the baseline after you hit the ball.