Grunting has been a topic of chatter on the pro tour for years.  Monica Seles was criticized about her loud grunting at Wimbledon in 1992 and may have lost the final because she tried to play silently.  This is not a new issue.  Top players from Rafael Nadal to Maria Sharapova exhale loudly with every stroke.  It is really kind of absurd to ask them to suddenly play “quietly” when the grunting is now an innate part of how they hit every shot.  Maybe they make a bit more noise in the crucial moments or when they are trying to hit the ball harder or when they are tired, but it’s not an effort to distract their opponent.  Maybe it’s confusing sometimes if a players makes a loud grunting noise and then the ball somehow sails softly across the net, but that’s a rare occurrence.  If a player is really concentrating, and is really “in the zone” then he/she shouldn’t really notice the grunting that much.  Teaching professionals should never instruct their young players to grunt.  Once a player has developed the habit, however, it’s really like many other, sometimes annoying, mannerisms that players acquire over time, e.g. what they do before they serve or receive.  Loud grunting may be annoying, but the solution is to stop the problem before it develops rather than trying to eliminate it once it’s established.