Tennis great Rafael Nadal has a new iPhone app

• App lets consumers capture and analyze video of ground strokes
• Users can compare their technique with Nadal and other players
• Nadal rarely does endorsements but made an exception for Vstrator

UPDATE: A stomach virus has knocked Nadal out of the Australian Open, Nadal said on Dec. 28.

SAN FRANCISCO — Tennis great Rafael Nadal is ready for his comeback.

Since a knee injury sidelined him after this year's Wimbledon, he's been out of action. But he'll be back at the Australian Open next month, and with a new iPhone app.

The new Rafael Nadal Tennis Academy App, developed with video-analysis firm Vstrator, will be available within the next few days on iTunes. It offers in-depth tennis tutorials of Nadal's strokes, along with Vstrator's easy-to-use video coaching tools.

"This helps you visualize how to become a better player," Nadal, the world's No. 4-ranked player, told USA TODAY in a phone interview.

The app (www.vstrator.com/rafanadal) lets consumers capture and analyze video of athletic motions such as ground strokes and serves. Video can be recorded or imported from a smartphone camera into the app. So-called "Vstrate" technology lets users highlight video to zero in on any part of their game.

Users of the app can frame video forward and back to compare their technique with Nadal and other players. Vstrator video can be shared via Facebook, Twitter, e-mail or text message.

The normally low-key Nadal, 26, rarely does interviews or endorsements. But he made an exception with Vstrator to reach out to fans, he says.

"You can use it anywhere — on the court or at school, and compare any shot of yours to a professional player," says Nadal, an 11-time Grand Slam champion. "It is a great way to learn tennis, and see how you can improve."

Vstrator hopes to "lead the sports community into the digital age and taking coaching and training to a new level," says Rob Autry, the company's CEO and founder.