Measuring power while running

[Danny poleg]

I would really appreciate help understanding how the watch measures my power (watts) while running if I only run with the watch and without any other product that is connected to the watch or measures watts

[freeheeler]

@Danny-poleg
it’s not a measurement it’s an estimation based on specific metrics that you store in the watch and that are measured with available sensors. and the rest will remain a secret to all of us

[Brad_Olwin]

@Danny-poleg Most other products including Stryd use estimations. There are insoles that measure force but they are not widely used. Running power is not as translatable as cycling power as running power cannot account for differences in terrain features on trails. I think it is only useful on smooth trails or smooth dirt roads and pavement.

[Łukasz Szmigiel]

@Brad_Olwin isn’t barometer also used to factor in the elevation?

[herlas]

One of the things that’s a must for wrist-power seems to be GPS signal. e.g. treadmil workouts = No wrist-power

The main difference between cycling power and running power is that the latter happens in 3 dimensions, and the cycling power is just one mechanical force to move your bicycle forward.

[isazi]

@herlas I think it’s even simpler than that for the bike, it is just the force you apply to the pedals (measured at the pedals, or along the way with some loss). The bike model is quite simple because all power is applied in the only connection between you and the bike

[Danny poleg]

@herlas So just to understand - the algorithm that calculates the watts - power, in case I only use the watch, relies on - speed (with the help of GPS), step- cadence, ascent and descent on the track using a barometer & HR.
thank you

[FunkyLarma]

The calculation for power is forces times by velocity. So in a cycling power meter you have the cadence or revolutions of the sensor. Then through the use of strain gauges you can calculate the force. This is why most cycling power meters also transmit cadence as it is fundamental to their function.

As previously mentioned running power is an estimate. They use all the data they have available and then secret sauce algorithm to provide you with a number. At this point there is no definitive standard on how to measure running power hence why there is so much variation between sensors. Stryd is one of the main players in the running power scene have a bit of an edge, whilst they are one of the few that appear to have been validated and do not actively use gps in their calculations they also hold patents that prevent similar development.

In my opinion gps should not be part of any running calculation, it is too variable to be reliable but as the technology and placement is limited there does appear to be many other ways companies can calculate a power estimate.
For the record I have used Garmin running power in the past and currently have nearly two years with Stryd.

[isazi]

@FunkyLarma I do not think Suunto uses GPS at all in running power estimation, in fact it works also indoor and with GPS disabled

[Egika]

@Danny-poleg said in Measuring power while running:

@herlas So just to understand - the algorithm that calculates the watts - power, in case I only use the watch, relies on - speed (with the help of GPS), step- cadence, ascent and descent on the track using a barometer & HR.
thank you

just guessing, but I highly doubt that HR is part of the formula, as it is how your body reacts to the power needed to keep you moving.
As @FunkyLarma states, power is force multiplied by velocity. For the force you need some good estimations, what to move against any friction, which is not trivial for running. But i guess there are lookup tables that correlate a certain running speed and body weight with the power.

What we know is, that Suunto has tuned the algorithms in a way that they match Stryd’s output very well.
Garmin produces different data.
This means running power data should only be compared between different runs done with the same device.

[herlas]

@isazi are you sure? At least in my limited number of treadmil workouts this hasn’t been the case.

Also tested some time back running through a tunnel and the power reading dropped to 0 as soon as GPS was lost as well.

• came across this one :

https://www.suunto.com/en-us/sports/News-Articles-container-page/run-with-power/

… Suunto 9 Peak Pro measures running power from the wrist combining GPS and barometric data.

[isazi]

@herlas strange, I can record power even walking indoor (but have not tested the S9PP)

[Łukasz Szmigiel]

@isazi isn’t it just calibrated outdoors?

[VoiGAS]

@Łukasz-Szmigiel Sorry for wakening this old thread, but maybe it is helpful:
Tried it today wirh the Race S, measuring Power also works indoor - at the end of an outdoor run. I was climbing the stairs to my flat in the 5th floor and it showed plausible values

Would be great to have a real indoor sports mode with power, like treadmill

[VoiGAS]

Update: Tried to trick the watch today on the treadmill, just used the running mode without gps.
Power is shown, but it was about 50% to high, same with the distance. The running mode doesn’t seem to use the correction factor like the treadmill mode - thats strange. Else it would work…