new Garmin Running Power algorithm – a shallow dive

Garmin’s update to its Vivoactive line boasts a few new features that were once considered advanced running features (2022) – namely running dynamics, including Garmin Running Power. It’s perhaps inevitable that old features eventually find their way onto new watches, but what is different this time around, for the first time, is that the Vivoactive 6 lacks the essential ingredient that is a barometer yet manages to offer running power. Let’s investigate what that means and how Garmin has likely achieved this feat for the first time.

Garmin’s running Power Calculation.

There are two ways to estimate running power. Market Supremo, Stryd, is validated against the ‘metabolic cost’ of running and probably uses the External Energy Summation Approach (EESA, Ron George). In contrast, others like Garmin use the Gravity Ordered Velocity Stress Score (GOVSS, Phil Skiba). Neither is accepted as correct, and each produces significantly different results. Every GOVSS approach by watch vendors yields different results, although some are similar.

Here are the components of the calculation according to Garmin. As you can see, barometric data appears the only way for the watch to know the altitude gain.

Or, at least, it was.

A Step Back

Let’s take a step back to explain why this is important.

When you think of elevation changes, you think of mountains. Dispel that thought. Think about how smartwatches determine the flights of stairs you ascend each day. You would probably guess it is based on accelerometer movement, but you’d be wrong. The barometers in wearables are so accurate these days and have been for years, to the extent that they can accurately detect elevation changes of a few metres as you go upstairs.

The same barometers are super accurate outdoors as you go up hills. The elevation recording issues you face outside are compounded by changing air pressure as you ascend and changing air pressure as weather systems move over you. Watches typically don’t have to deal with those problems over the 5 seconds it takes to go upstairs to the toilet!

What happens outdoors when determining elevation changes (simplified) is that the GPS in your watch takes 2D and 3D readings. The latter are periodically used to recalibrate the small-scale elevation changes from the barometric altimeter.

Back to the Vivoactive 6 and back to the future of running power algorithms?

So what’s probably happening here is that the Vivoactive 6 only uses 3D GNSS/GPS to determine the small-scale elevation changes experienced by the kinds of runners who would buy a Vivoactive 6.

That probably won’t be as accurate as barometric data, but it might be accurate enough. IDK. In any case, Garmin still estimates another component, wind, from a weather forecast regardless of the proximity of wind shadows and localised effects, so Garmin Running Power is a best guess metric.

Evidence

Well, tell me how else Garmin might do it!

Further evidence can be gleaned from the GNSS chipset. You may have noticed that some recent Garmin watches lack Dual-Band GNSS and SatIQ. While it might be tempting to assume Garmin is disabling multiband purely for product tiering (Garmin?! Surely not!), the reality appears more nuanced.

The Vivoactive 6 doesn’t use the older Airoha chipsets seen in other mid-range Garmin watches. Instead, it appears to adopt Synaptics’ next-generation SYN47762 GNSS chipset, a modern, low-power single-band solution that adds support for all major constellations, including BeiDou and QZSS. This chipset is explicitly designed for wearables and compact IoT devices where energy efficiency and small physical footprint are key.

Although the SYN47762 doesn’t support Multiband GNSS or SatIQ, it incorporates advanced signal processing and tracking algorithms to improve performance.

While it doesn’t use a barometric altimeter, Garmin probably leverages enhanced elevation filtering algorithms or sensor fusion techniques to smooth out transient altitude noise. This could provide sufficient relative elevation accuracy—not for mountaineering, but for tracking small-scale elevation changes (on the order of metres) over a few seconds, which is critical for running power calculations.

Take Out

In short, Garmin’s use of a next-gen GNSS chipset—albeit not a top-end multiband one—suggests a deliberate tradeoff: sacrificing absolute vertical accuracy but gaining energy efficiency and adequate relative elevation tracking to support applications like GVSS-based running power estimation.