In a rare interview with Outside Magazine, Jay Blahnik, Apple's director of fitness for health technologies, spoke about the Apple Watch's impact on users' fitness since it launched, the importance of the Stand ring, and how integration with third-party apps will change the game.

Once third party Apple Watch apps are able to integrate with the Watch's sensors, Apple still doesn't want them to take over the user experience of the device, Blahnik said. But how customers use the Watch will be up to them, he said, and third party apps will have a lot of value for athletes in sports other than running.

"We’ll be keeping Activity as the centerpiece -- workouts that happen in third-party apps will be aggregated and shown in the app -- but we’re not expecting the hardcore cyclists to use our Workout app instead of Strava," Blahnik told Outside. "If you’re really motivated by that app, the last thing we want to do is to tell you to leave. We feel strongly that if the activity rings can aggregate your day, we’re happy to have you use the apps you want to record the workouts you’re doing."

The Apple Watch isn't exceptionally innovative in terms of its sensor suite -- it still measures mainly activity and heart rate, features found on most leading activity trackers. But third party apps will allow the Watch to use those sensors in innovative ways, Blahnik says: golf and tennis players will be able to get data on their swings from the Watch's accelerometer. And the Apple Watch could potentially bring in data from smart clothing or smart dumbbells, so CrossFit or other training apps can have all the data they need to guide a user's workout.

Another edge that new app integrations will bring is a social one: For some people, Blahnik said, the motivator they need is social support. That could mean integration with Nike+'s leaderboard or with an app like Motigo, Blahnik said. Motigo feeds the user personalized audio messages from friends and families to support them. Or the Equinox Apple Watch app that helps people integrate their fitness into their day-to-day routine.

"If you’re a regular indoor cyclist and love the Spinning classes, the app will prompt you to register 25 hours in advance," Blahnik said. "And you’ll be able to book your favorite bike right from your wrist. That has nothing to do with tracking, but it may be that one thing that gets you to make a commitment to fitness."

So far, Blahnik said, the Apple Watch's "three ring" user interface, which prompts users to move, exercise, and stand each day, is working as a motivator. Apple Watch users become obsessed with closing the rings every day and, even more importantly, create a positive and holistic framework for thinking about activity.

Especially important is Apple's Stand ring, which tells users to move every hour in order to complete their daily goal. Sedentary time is unhealthy even for athletes who run or bike a lot, Blahnik said. An app that just pushes someone to walk 10,000 steps or burn a certain number of calories can be unhelpful to someone who knocks out that many steps out before lunch -- and then doesn't receive any motivation for the rest of the day.

"We’re hearing from elite athletes who say, 'I never really thought I needed an activity tracker, because I get up in the morning and do a three-hour bike ride or I run 10 miles. But I found out that I’m sitting a lot.'," Blahnik said. "They’re motivated by that. Or they’re learning that they’re actually burning more calories than they realized by moving throughout the day. It’s not just a beginner sort of story."