Apple has announced that in 2013, the company earned over $10 billion from the App Store, and Apple's developers have earned $15 billion from the App Store. In the release, Apple attributed their success to the "stunning apps that took advantage of the redesigned user interface" and named some "surprise hits" from the year, including one fitness app -- Protogeo's Moves app, which became a paid app as recently as September of last year.

Protogeo has made a series of proactive steps since Apple launched iOS7 and announced its motion co-processor, called M7. Before Apple's announcement, Moves was already taking advantage of Apple's accelerometer to offer users passive tracking, and a few weeks later, in late September, CEO Sampo Karjalainen told MobiHealthNews he was unafraid of potential competition that might come from other companies having access to M7.

“Tracking is first, but then the challenge is to really make sense of that data, and help [users] change their behavior, those are really important,” he said at the time. “And that’s something we are working on with new features on top of that data. But the first step is to make activity tracking work really well. And we have the best technology at the moment.”

Two months later, in November, Protogeo updated its app to make use of Apple's M7, and at the same time added a price tag to the previously free app. It started out at an introductory rate of $1.99 and then in December the company raised the price to $2.99.

With M7, Protogeo claims it was able to increase the phone's battery life while using the app by 40 percent on a typical use, and the company said the improved battery life will be on all iPhones, not just the new iPhone 5s. Karjalainen said at the time the new battery saving mode that they launched with is remarkably better and the value that people get out of it is very similar to what the activity tracking gadgets have to offer, which cost around $100.

While Apple only highlighted Moves in its announcement, many other fitness apps have taken advantage of Apple's new motion co-processor.

Shortly after Apple announced the new features with iOS7, the company highlighted Nike's new passive tracking app, Nike+ Move, which some have reported is a gateway app for those interested in purchasing Nike+ FuelBand.

In early November, RunKeeper updated its app to include passive tracking in a feature called Pocket Track. If users chose to opt in, Pocket Track will automatically track runs or walks throughout the day and users can add the passively tracked data into their RunKeeper accounts at any time.

Most recently, Fitbit announced the addition of passive tracking to its app. The feature is called Motion Track and, while the app only tracks basic activity, it could also introduce users to the Fitbit portfolio of devices, complete with small clip-on activity trackers, wrist-worn wearables and most recently, and a new line of accessories specially designed by Tory Burch.