This post will provide a bit of background but then specifically discuss the pros and cons of GRP compared to the competitor products STRYD and RunScribe (there are others but I wouldn’t consider them yet if I were you).
Training or racing by PACE is great; but doesn’t work too well on hills. Training or racing by HR is great; but there is a lag in the reaction of your HR to your effort by about 30 seconds. Training or racing by RPE is great; but usually it’s only the better athletes who can do it well.
Power gets around all of these drawbacks and is a proxy for effort
Benefits of a Running Power Meter
There are exactly 14 benefits from a running power meter. Not 13 and certainly not 15 😉 This link from Coach and Author JIM VANCE is written for STRYD but the benefits equally apply to GRP.
I was sceptical at first. However with over a year of use (of STRYD) I have definitely benefited (& that means I am 100% sure) from: pacing on an undulating HM (or 3); hitting intensity targets on hill reps; relieving the occasional monotony of training by using something else to pace to; getting differently motivated to hit power-duration PBs. The latter probably sounds a bit weird but once you get into POWER…it’s pretty cool to play with power duration curves.
- It’s free. Everyone loves a freebie. My grandma always told me that ‘you get what you pay for‘ but I always thought she was a cynic, as lovable as she was.
- If you are a current Garmin Connect user then GRP’s data just slots into your screen and post-race charts near-seamlessly. It just works. With no configuration as such. (See footpod for exception)
- If you are an existing owner of a compatible watch it’s also reasonably likely you’ll own one of the required accessories (below)
- Garmin provide 5 free apps which provide most of the key elements of usability. Meaning: power alerts, lap power, power zones
- Uniquely GRP accounts for wind
- Uniquely, you can choose to just display your data or display and save it. You might not want to save it as saving it could later ‘confuse’ other sports data systems you use where you also store BIKE power data.
- A great, low risk way into running with power. Almost a ‘try-before-you-buy’ scenario if you were considering STRYD/RunScribe.
- The required RD sensors each use long-life coin cell batteries. You won’t have to worry about having to charge up another sensor.
- 3rd party data analysis sites like Golden Cheetah, Training Peaks and SportTracks (MOBI) will be compliant to the data very quickly. SportTracks 3.1 desktop requires extra, annoying work with paid-for plugins but is compliant now.
- GRP requires a compatible, high-end Garmin watch. Namely a Fenix 5 or Forerunner 935 (+Chronos). That’s the choice. In the future, it’s likely the Forerunner 645 will support GRP. Probably also a 74XT if released in 2018.
- GRP requires Garmin Running Dynamics data (VO & GCT) from either a Garmin RD-POD or Garmin HRM-RUN/TRI.
- Running Power is NOT properly native to the Garmin Running Environment. It CANNOT be used everywhere like, for example, pace or bike power or HR can. So there are NOT inbuilt RUNNING metrics for lap power, power alerts, power zones, averages and so on. NONE of that natively exists. BUT see above for the more than acceptable workarounds by using the various apps and the configuration options.
- The WIND element of the GRP power calculation is suspect. It relies on offline weather forecast data recently downloaded from a smartphone – this is then derived from the compass heading on your watch. Generic weather for your locality clearly will not apply to areas of building or tree cover. Plus the forecast wind speed/direction is not always the same at true ground level. Advice: Disable wind adjustments.
- The power calculation is made more accurate by more accurate PACE. By default it uses PACE from GPS or from GPS+GLONASS. Advice: Use a properly calibrated footpod as the source of pace (STRYD is best for accurate pace 😉 ). Otherwise you might face the ‘garbage-in’ ‘garbage-out’ scenario.
- The power calculation relies on GCT and VO from one of the RD accessories previously mentioned. I suspect, but don’t know for sure, that VO/GCT will vary depending on the RD accessory you use. Just make sure you always use the same source.
- If you use the RD-POD you may get different results from clipping it to differently elasticated garments around your waist. Meaning: wear the same shorts/tights/trousers. Readings may also vary with your changing muscle/fat makeup in that area.
- Your data will likely NEVER be comparable to data from STRYD or RunScribe. So if you switch from GRP to RunScribe down the line then your GRP data will be of ZERO use to you. You will have to start again with your power zones and power-durations. Suggestion: Use GRP for a month, or so, and then evaluate how much you are using running with power. If running with power is of peripheral use to you then you have saved an expensive purchase of STRYD/RunScribe.
- Data collection relies entirely on your watch. The 935/F5 have GREAT battery lives but if you don’t press go or run out of juice then no power is stored on the accessories (unlike STRYD and RunScribe)
- Probably requires a correct and up-to-date weight & height values in your Garmin Connect profile…no more kidding yourself 😉
The Garmin Running Power apps really are cool. I like them. They are better implemented than the competition. However I have reservations about the power data itself. And that is a pretty big area to have reservations about.
If you already have the necessary kit then it is a ‘no brainer’ to try out GRP and see if you get any benefit from running with power – lots of people don’t; lots of people do !!.
I suspect the fall-out from the release of GRP will see that interested runners or casual runners will end up being the ones that use GRP on an ongoing basis. More serious runners/triathletes will probably end up using either RunScribe or STRYD.
Here is some bedtime reading for you: some delving deeper into GRP; some looking at it from a different perspective.