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Croatian tennis player Ivo Karlović set the official record for the fastest-ever-recorded serve when he fired a 156-mph missile at his opponent at the 2011 Davis Cup. The serve took 34 hundredths of a second to cross the 78 feet of the tennis court, roughly the time it takes to blink. And just like that, the 6-foot-10-inch Karlović moved atop the record books, shaving 1 mph off the previous record — an easily measurable achievement, but one that was almost invisible to the naked eye.

We’re awash in sports data these days, with heat maps and statistics on everything from soccer player running patterns to hockey assists to field goal attempts on the basketball court. But while that’s brought the armchair athlete closer to the action, there’s still a fundamental barrier between the athlete and the fan. The numbers tell us almost everything — except what it feels like to try to get a racket on Karlović’s serve.

The next frontier of the sports experience will use technology to give fans a visceral, on-the-court feel for the game by, for example, facing a fuzzy green projectile traveling at you faster than an Acela train.

To that end, fans at this year’s Australian Open donned an Oculus Rift virtual reality headset in a faux court setting to grasp the speed of a pro’s serve. The ReturnServe experience displayed a virtual court where users faced down an animated version of a real player. Using data collected from real matches, the app recreated an actual pro serve and gave fans a chance to return it using a motion sensitive racquet.

The opponent may have been virtual, but the raised blood pressure and dilated pupils that came from standing in the firing line were all too real. After they flailed at the serve, users got feedback on their return games. The idea was to put all the data we see in context, said Elizabeth O’Brien, sports marketing manager for IBM, which created ReturnServe.

“You’re used to seeing players that are serving at 80, 90, 150 mph,” O’Brien said. “Here’s what 100 mph serve would look like to you, let’s see if you can return it.”

Immersive fan experiences aren’t just virtually putting fans on the court, but are also increasingly using technology to broadcast the athlete’s experience on the court into living rooms. For athletes, it means wearing devices like Google Glass as they pancake a 300-pound defensive end or chase down a Federer volley.

This past March, former Minnesota Vikings punter Chris Kluwe gave a preview of the experience in a TED Talk calling for the use of augmented reality in football. In it, he showed himself being tackled while wearing the headset.

“Fans want that experience,” Kluwe said. “Fans want to be on that field. They want to be their favorite players, and they've already talked to me on YouTube, they've talked to me on Twitter, saying, ‘Hey, can you get this on a quarterback? Can you get this on a running back?’”

It isn’t just football. The Sacramento Kings were outfitted with wearable cameras for a shootaround earlier this year and one techie wore a pair on the ice for an amateur hockey game.

But before the tough guys bring it to the field for game play, the technology will debut on the sidelines. The Philadelphia Eagles plan to outfit the team’s cheerleaders with Google Glass this season and pair it with technology that can take streams from multiple sources and then display the views on the scoreboard.

For the sports fan, it presents a whole new understanding of what it means to be in the game. Soon you can be pressured into coughing up the puck in your own zone from your own home or feel the joy of seeing a ball sail almost 60 yards through the uprights to win a game. Certainly, it’s going to be harder to a mouthy Monday morning quarterback when you know what it feels like to get blindsided and lose the ball. Virtually, at least.