Apple has quietly made a fairly significant change to how and when running power is calculated in the Apple Watch, which will affect ultra and trail runners the most. Fortunately, this is a good change.
This change is part of a handful of other changes being made as part of the latest Apple WatchOS software, currently in public beta as 9.4, which is likely to be released in the near future. Apple has confirmed that these changes are planned.
In total, there are basically three race-specific changes made in this version and the previous version:
1) Running power now includes “walk” periods (specifically in the Outdoor Run profile)
2) Runway mode will now ‘snap’ to 100m sections if within 5m of that point (just like the Wahoo RIVAL does)
3) Treadmill mode now shows a new summary at the end of the workout with times per loop (in 9.3)
Additionally, while not actually part of 9.4, note that Apple also rolled out Running Track mode for a number of additional countries at the same time. I have outlined all of them here.
The power change may sound minimal to non-runners, or even to road runners, or those just thinking about interval-type scenarios. But really, it’s a pretty massive shift for trail runners, or anyone else on steep terrain, where the Apple Watch would previously fail to measure running power. Specifically, scenarios where you might have made a significant effort up a steep incline, but Apple didn’t calculate any running power. As such, you couldn’t use it for pacing (and so it couldn’t be used to calculate any power-based training load/impact in third-party apps). This despite the fact that these steeper sections were probably the ones with the highest effect.
Apple now agrees and has implemented support for running power during walking segments, joining the rest of the industry capturing this data.
First… as always, a quick reminder that there are no agreed-upon standards for the definition of driving force. As such, each company does it differently – either very different or slightly different, depending on which biomechanical components they decide to include in their calculations. Another reminder that while it’s practical mentally if running and cycling strength numbers match up for a person, there’s no biomechanical reason why it should happen (and in fact, there are many reasons why it shouldn’t).
With that, let’s look at what Apple did based on some recent training programs. Here are some before/after update workouts to show the differences. I did these over the previous few weeks and didn’t have Stryd or anything else with me. Only Apple power and Garmin power, both wrist-based. If I were focused on a broader set of circumstances, it might mean more. But I already did a comparison of COROS/Polar/Garmin/Apple running power (Suunto also added running power, but that came later).
Here’s what some ranges looked like before the change; you can see every time I recovered (walked) the power dropped completely on the Apple Watch. I’ve highlighted the yellow part where you can see that the Apple Watch running power value has a flat line to zero between each interval as I walked. Whereas the other units showed power values.
Now compare that to another workout (structure and time) and you can very clearly see the low level of force exerted during the recovery portions:
Again, the main point/benefit here is not really to capture running power during recovery. Rather, it is to capture running power on steeper climbs, such as those in the mountains, where many (if not most) trail runners will effectively fast walk the steeper climbs. In these scenarios previously, the Apple Watch would not calculate any running power as it did not reach the ‘Running’ detection threshold. Now it will, as any forward movement is counted.
Fun fact: There is actually a track that zigzags up the front of this. It was gloriously boring to run down, I would have rather hiked up.
Now despite recently flying halfway across the world from the flat Netherlands, I landed in the also flat Florida. As such, my ability to find a nice steep mountain is limited. The best I could do is a very short hill here in Amsterdam, just steep enough, short enough, to prove my point. Wearing an Apple Watch with the previous 9.3 firmware, and then another with 9.4 beta, you can see side-by-side how they handle the same section as you speed up this steep section.
Below, it shows how the older firmware in teal – which I’ve highlighted with yellow spots – struggles whenever I walk, be it on flat or steeper slopes. Whereas the newer firmware in purple does better. And in this case, not just previously struggling to show nothing – but also struggling with random inaccurate spikes at lower speeds. Again, fixed with the newer firmware.
Now, if only they would roll out running track mode to the Netherlands, I’d be happy. I mean, it’s a small country – I’m not asking for too much, am I?
With that – thanks for reading!