After talking with Tim Cook onstage at the March 9 "Spring Forward" media event, model Christy Turlington Burns has kept a weekly blog on Apple's official website with updates on her preparations for the London Marathon next month.
In this week's post, Burns mentions in passing that the Watch will not only learn a user's stride after a few exercises when paired with an iPhone, after a while the Watch will be able to act independently in tracking fitness-related stats without needing to be tethered to an iPhone at all (via MacObserver).
The post, titled "The Art of Vacation Training", finds Burns on a bit of a break from her usual training regimen while on vacation with her family in the Caribbean. Still finding time to put in a 14-mile run in one day, Burns discusses how her personal Apple Watch has since learned her stride and speed, the Watch becoming less reliant on the iPhone in the fitness-tracking departments the more she uses it.
I switched up my runs between the treadmill at the hotel gym and outside. After you run with Apple Watch and your iPhone a few times, the Workout app knows more about your stride. So you can run on a treadmill or outside without your phone and still get a really accurate workout summary.
Apple's presentation of the device, ever since its reveal last September, has been of a Watch in nearly constant need of contact with an iPhone. Although Burns' blog post only appears to confirm the Watch's fitness-focused apps can sufficiently work sans iPhone, it's still an interesting piece of information, especially for users planning to use the wearable as a sole workout device.
Check out the rest of Burns' blog post, and her earlier entries, on Apple's official website.