Tennis Coaches Put Video in Play Petr David Josek/Associated Press Gilles Simon of France is among the increasing number of tennis players and private coaches who are turning to detailed video analysis of their play. PARIS - When Gilles Simon faces Roger Federer on Sunday in the fourth round of the French Open, Simon will have multiple weapons at his disposal - his speed, his signature two-handed backhand down the line and his world-class ability to absorb world-class power and snuff out attacks that would sink less resilient men. He will also, if he so chooses, have the benefit of extensive video analysis of Federer's tactical patterns and tendencies. Tennis has long been slow to embrace the game-film culture pervasive in other professional sports. But that is changing. Tennis Australia, the governing body of the sport in Australia, now has an extensive video performance analysis unit that can deliver up-to-date footage and pattern breakdowns on future opponents to its players, whether they are playing in Wimbledon or in a challenger in Tashkent, Uzbekistan. "They don't have to go to YouTube anymore, or at least not very often," Darren McMurtrie, who runs the program, said in an interview in Melbourne, Australia. "You can use it for all sorts of things, and I think it's been very useful," said Samantha Stosur, a former United States Open champion and Australia's top female player, who has made extensive use of the detailed statistics and curated video clips. The other Grand Slam tournament nations - France, the United States and Britain - have similar, if less extensive, systems. "They've got a bigger budget than we do," Patrick McEnroe, head of player development at the United States Tennis Association, said of the Australians. Video analysis is also being used more by private coaches, including Jan De Witt, the German coach whom Simon, a top-20 player, hired in April in part because of his relentless tactical focus. "I chose Jan because I think he can make me very comfortable with my choices," Simon, a Frenchman, said in an interview after his five-set victory over Sam Querrey in the third round. I make a lot more choices on the court than most of my opponents in terms of tactics and strategy. I didn't play the same in my first couple of rounds as I played against Sam, whereas Sam played much more the same style against everyone. He has the weapons he's going to use - his serve, his forehand. Most players are very focused on what's happening with themselves, on their side of the net. I'm much more focused on what's happening on the other side of the net. So the tactics are very important to me, and Jan is very good with this, especially with the help of the video. Coaches and tennis parents have been filming matches and practice sessions on a regular basis since the advent of the video camera. But one of the first tennis coaches at the elite level to make use of video to dissect opponents" patterns was the Australian Darren Cahill when he was coaching Lleyton Hewitt and Andre Agassi in the early 2000s. He received his inspiration from Australian rules football, which his father, John, played and coached at the professional level. Cahill said he bought a system called SportsCode from the Australian Football League. "The A.F.L. clubs got it from the N.F.L. and basketball in America, and I used it for a lot of the Lleyton Hewitt matches when I was with him and then took it on through with Andre," Darren Cahill said. I think it's under-tapped, value-added in tennis, and we don't really go after it enough in coaching, and I think we're finding more and more people are starting to invest in that. Cahill kept his usage of the system a secret while he was coaching Hewitt and Agassi. "Smart guy," Stosur said in an interview on Saturday. Cahill said he did so "because I thought it was an edge, simple as that." Maintaining that edge was labor intensive. Cahill said it could take him "six or seven hours" to go through footage of a three-hour match, isolating and analyzing the elements worth highlighting to Hewitt or Agassi. Cahill said Agassi liked the video package short and sweet. "Ten or 15 minutes of good stuff and that was it," Cahill said. But I used it a lot. For me to be able to deliver a message to him or find out where a guy is serving on a big point or to get a feel for what side he might cover at the net or to get a feel for Andre as well, if he's giving up too much space on the forehand side when he's going backhand to backhand, we could designate the video to find those areas. Performance analysis systems have become more nimble and sophisticated, but long hours remain part of the job description. In Melbourne, at Tennis Australia's new video performance analysis center, McMurtrie said he had only one day off in December and January: Christmas Day.