Helping prepare the courts and volunteering at the Grapevine $50K Women’s Pro Circuit event at the Hilton DFW Lakes has helped me learn a lot about the game at the professional level. When I was helping install a new net, I asked a local pro about specs. for net tension. As it happens, there are none in the formal rules. There are rigid specs for height, but not tension. The USTA does, however, have a procedure for establishing relatively uniform tension at tournaments.
First, the center tape is completely loosened. The net tension is cranked up until the center of the net is at 40 inches. Then, the center tape is applied to bring the net center down to 36 “. The USTA official uses a measuring stick. For a singles match, two sticks are placed to prop up the net tape in the doubles alley so that the height over the inner line is exactly 42”. The sticks are not used for a doubles match as the net posts are supposed to be 42.5″ so that the net height is exactly 42″ over the outermost line. If not, the net tension is reduced until the proper height over the outer line and center are reached.
Presumably, this procedure applies for US hardcourts. I don’t know if the posts for a clay or grass court could handle this process. The posts at Wimbledon, for example, are not all that well anchored in the ground and this tournament is famous for its ‘loose’ nets.
Filed under interesting factoids that every tennis player should know 🙂 What you should also know is that your typical court is setup so that the net height at the sideline of a singles match is probably lower than it should be. I remember as a kid playing in tournaments that people would often measure net height at the center, but never at the singles/doubles sidelines. So, if you go to a tournament and play a singles match and see sticks propping up the net in the doubles alley, those down-the-line passing shots need to be higher than you might be used to in order to make it over the net.
Addendum: I’ve noticed the last couple of days that the USTA officials measure the center net height at the end of each set.
The Algorithmist 
Wow! A women’s pro tournament! Was Maria Sharapova there? Can I get her autograph?
JT, I think you’re turning into a stalker 🙂 No, she’s not in this tournament. These ‘challengers’ as they’re known on the men’s tour are usually $10-$50K tournaments. The primary goal is tour points to increase ranking to a level that makes it easier to get into top-tier tournaments. You won’t see top-ten or even top-50 players at these tournaments. However, the level of competition is very high. There is so much talent in the tour these days that there is not very much difference between #50 and #100.
Sometimes well-known players resurrect their careers on the challenger circuit; the most notable (recent) example being Agassi.