Why Apple’s Workout API was the most exciting aspect of watchOS 10

We speak to Eric Charles about some of the innovation behind Workout APIs
Apple Workout API golf
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While eyes will be drawn to the new design language and the Smart Stack widgets in watchOS 10 – there was a much bigger change further down the billing.

watchOS 10 is one of the biggest shifts in the UI for a long time, but its Workout APIs could end up being much more transformative.

Developers have long had access to the full line-up of biometric information served up in Apple Health. That meant that running and fitness apps have been able to take heart rate data and use it as part of their own algorithms.

> watchOS 10: Hands on with the new look OS

But now Apple is enabling them to access the raw data from the motion sensors, to build their own apps. And the quality of that sensor data is exciting.

With the addition of Fall Detection on Series 6 and Car Crash detection on Series 8/Ultra, Apple has seriously upgraded the accelerometer. And that means it’s capable of being leveraged for applications beyond most smartwatches.

The three-axis gyroscope included in the latest generation of Apple Watches captures angular velocities at 4,000 degrees per second. And the accelerometer sample rate is now 800 Hz or 800 times per second. The max sample rate of older Apple Watch devices was 100 hertz, so accuracy has been ramped up dramatically.

And tapping into this incredibly rich sensor data will herald a host of new apps – and Apple has already been working with select partners to show off its capabilities.

At WWDC it showed off golf and tennis swing tracking, which are obvious examples of how developers could utilize this data.

> 68 Apple Watch features and tips

And other sports applications also spring to mind, and we could see an expansion of the advanced analytics we’ve already seen, such as vertical oscillation, cadence tracking, FTP for cycling, and running power.

Eric Charles, Apple Watch Product Marketing, explained to Wareable how developers can also take and build on these metrics as part of their own apps, which will improve the third-party offering of fitness apps even further:

“If a third-party developer wants to create a new power zone experience of their own, they can grab our FTP estimates and use that in their app. So we're hoping this facilitates a widening of the lens,” he said.

And Charles believes Workout API will make it easier for developers to create rich workout apps.

"It takes the thought process out of a developer wondering if they need to do the work or if that work is already being done. If the calculation of those measurements is already being saved, they can just grab and use them,” he continued.

Importing workout plans

AppleWorkout API training peaks

Workout API also enables training apps such as Training Peaks (above) to schedule sessions that sit within the Workout app directly. So instead of choosing a general Outdoor Run workout, you choose your scheduled 8 x 800m interval session and start it right from the wrist.

Not only is the session placed within the Workout app, but the structure is meshed within the Apple workout builder, so you can follow it exactly.

“The training plan just comes straight across with the timers, intervals, and modalities. It's all there for someone just to simply jump in and follow. So it's not just a standard timer,” Charles confirmed.

What’s more, users will be able to see a seven-day view of scheduled workouts, and a history of the seven days previous.

Finally, the Workout API also covers the use of the iPhone as a secondary screen for workouts. 

Apple introduced this in watchOS 10 with cycling, which will show core metrics tracked by the Apple Watch, and any data from attached Bluetooth sensors, on the iPhone screen.

Apple is also expanding this via the Workout API, so other apps will be able to use the iPhone as a secondary display, to add a secondary dimension. 

While much of the history of watchOS has been about locking people into Apple ecosystem, Workout API is designed to help people use their Apple Watch and the apps they love together.

Apple Watch's biggest advantage over the likes of Huawei, Amazfit and other excellent budget smartwatches is its versatility, driven by the App Store. And Workout APIs make the Apple Watch even more versatile. 

TAGGED Apple Watch

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James Stables


James is the co-founder of Wareable, and he has been a technology journalist for 15 years.

He started his career at Future Publishing, James became the features editor of T3 Magazine and T3.com and was a regular contributor to TechRadar – before leaving Future Publishing to found Wareable in 2014.

James has been at the helm of Wareable since 2014 and has become one of the leading experts in wearable technologies globally. He has reviewed, tested, and covered pretty much every wearable on the market, and is passionate about the evolving industry, and wearables helping people achieve healthier and happier lives.

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