Coach feeds deep ball to the deuce side. Player moves back and hits forehand cross court. Coach feeds another ball shorter to the advantage side. Player moves inside the baseline and hits forehand inside in.
Movement back and forward is a reason for many mistakes in tennis. Players don't like (or don't train enough) to move behind or inside the baseline so they have to work more with their racquets to make shots consistently. Movement back is a necessity to deal with deep and difficult shots because hitting from the waist level (moving back) is much easier than struggling with the balls over the shoulder (staying on the baseline). Movement forward to the short ball is a primary goal to be more aggressive and win more points. By contacting the ball earlier, the player doesn't have to use so much spin (higher point of contact = easier clearance) and opponent's recovery time is much shorter.
World Rugby has reportedly conceded Aaron Smith's disallowed try in the World Cup final should have stood.
"It is not only useful for staff who are experienced but a valuable tool for those subject staff who have to take teams."
The variety of sessions across sports - sometimes we steal session ideas from one sport and use them with another.