The U.S. Open tennis tournament begins tomorrow and with it comes a two-week period in which tennis interest in the United States hits its annual peak. Just in time for tennis buffs comes an interesting, and more importantly, an effective improve-your-game video.

"Visual Tennis" with San Francisco teaching pro John Yandell has recently been released by Atlas Video of Bethesda, Md., (1-800-999-0212 or 301-907-0030) 60 minutes, $29.95. Yandell created "The Winning Edge" (45 mins., $29.95) in 1985, using John McEnroe and Ivan Lendl as models for messages on how to master the strokes of the game. Yandell's new book "Visual Tennis," the printed word from which his new video was produced, has been released this month by Doubleday ($16.95).

"Visual learning is revolutionizing the nature of sports training," Yandell points out. "The use of visualization and mental imagery are already well established in Olympic and professional sports. The 'Visual Tennis' video is designed to allow tennis players at all levels of ability to use these same techniques and develop classical stroke production."

Yandell creates still frames (four for basic strokes and six for the serve) at key points in each stroke. He then asks players to convert these stroke keys into visual images they can call upon when playing, or whenever they do some "off-court visualization." These images help to keep all the parts in the right places during a stroke. Repetitions develop proper stroke patterns with muscle memory drills to correct flaws.

Sounds highly technical, but Yandell makes it simple and clear. One viewing won't cure all problems, but this kind of mental approach and some returns to the video for help should bring about improvement. It's all designed to create lasting images of the proper execution of each stroke.

In "The Winning Edge" with McEnroe and Lendl, there is emphasis on practicing with bouncy music. Lendl, who has speakers hung in the trees around his practice court notes, "Music gives you rhythm and inspires you to play your best." McEnroe adds, "Music is the only thing that makes practice bearable."

With or without music, Yandell leaves the impression if you do it his way, your game is headed for improvement. He has a legion of students who agree.