The goalkeeper's heart rate skyrockets just before the penalty kick. An exhausted mid-fielder flags on the pitch and needs to come out of the game. And the coach knows these things as they happen.

That's the future of soccer—or football, if you prefer—in the major leagues. Adidas today announced Major League Soccer teams will begin using its miCoach Elite System, a set of personal fitness tracking devices that send data about each team member to the coach in real time, starting with the upcoming All-Star Game. The technology tracks each player's movements, speed, heart rate, "power output" (similar to exertion), positioning, stamina, and a few other physical and physiological metrics.

At the heart of the miCoach Elite System is a "cell," or small data-capturing device (shown below). It contains a heart rate monitor, accelerometer, GPS tracking device, magnetometer, and gyroscope. Players wear the cell in a special garment with a protective pocket that positions the cell between their shoulder blades. A tiny antenna on each cell sends the data being collected via radio frequency to a receiver. The receiver then transmits the data via Wi-Fi to an iPad, presumably in the hands of a coach, trainer, or medic. The professionals on the sidelines then have up-to-the-moment information about what's happening on the field.

The Elite system is a more advanced version of the consumer gadget miCoach Speed_Cell ($70), which anyone can buy and insert into a special cleat (sold separately) to track their sports activity. This device doesn't have real-time data reporting capabilities, but you can see your own on-field statistics via an app after you've finished training or playing a game.

The technology will be deployed across all of Major League Soccer in 2013, but start with the upcoming All-Star Game in the U.S. The data being collected will only be visible to coaches and players, with individuals clubs deciding how to share the information among the team. Fans and sports journalists won't get any new insights into the stamina of their favorite players just yet, although Nelson Rodriguez, executive vice president of game operations, said it's possible it may happen in the future.

After the event, an adidas representative followed up to mention that fans will indeed get a taste of the stats. When miCoach Elite debuts at the All-Star Game in Philadelphia, "adidas will be launching a miCoach tab and app on the adidas soccer Facebook page. The app will give fans access to real-time stats, straight from the pitch. This will serve as the home for all fan-athlete interaction, stat-sharing, and miCoach Elite System integration. [This will be] a peak to what type of fan engagement could come when the team-tracking system rolls out league-wide in 2013 with MLS."

For more from Jill Duffy, follow her on Twitter @jilleduffy.