Back when Apple announced watchOS 27 back in June earlier this year, there was one new feature that piqued my interest more than the promise of a smarter version of Siri or a Workout Buddy that now operated more standalone. Apple revealed that it was delivering more accurate distance tracking during walks and treadmill runs. It’s primarily doing that by making improvements to the algorithms that help to calculate the distance covered when you step onto that belt. It’s website states that ‘improved motion tracking algorithms help measure the distance of your treadmill runs and walks more precisely straight from your wrist.’ As a runner that does his fair share of runs on a treadmill (and not just because it’s got cold outside — treadmill running is great for specific pacing and incline drills), I liked the prospect that the best smartwatch ’s indoor activity credentials could now match its very solid outdoor performance — which I tested on the London marathon course’s infamous GPS black spots . So, has Apple actually managed to deliver more accurate distance tracking for indoor runners? I’ve been spending the last couple of months testing the feature across the best Apple Watches — including the Apple Watch Series 12 and Apple Watch Ultra 4 — to find out. How I tested
(Image credit: Getty Images) I began my testing using the beta versions of watchOS 27 running on the Apple Watch Ultra 3 and the Apple Watch Series 11. When watchOS 27 was given a public release, I also strapped on the Apple Watch Ultra 4 and the Watch Series 12 to see how Apple’s latest smartwatches fared indoors. I didn’t have my own treadmill (or indeed, have the room to house one), so I relied on the treadmill at my gym. While I did my best to stick to the same treadmill for these test runs, that wasn’t always possible. That did mean I’d be stepping onto treadmills of various conditions and belt wear, which does have an impact on the reliability and accuracy of the treadmill distance tracking feature. With the Apple Watch strapped alone to one wrist, I had a Coros watch on the other paired to the Coros Pod 2. This foot-worn pod is designed to track distance, among other metrics, and was an additional source of data that could offer a more reliable picture of my running distance than the motion sensors that usually do that from the wrist. I used the foot-worn pod as a control device, the same way we use the best heart rate monitors to test the readings from smartwatches. With watches on wrists and the pod on my feet, I captured a range of runs covering different paces and distances. That included short one-mile test runs, steady hour-long runs and interval runs during which I mixed up my pace. I stuck to the same incline for all runs and used Apple’s own Workout app to track the workout. Apple suggests tracking an outdoor run of at least 20 minutes to calibrate the watch and help those algorithms do a better job of understanding your stride length, and in turn, deliver more accurate distance tracking. I did that with each Watch I tested…
