Garmin Running Power & Wind

Garmin’s recent Running Power app/data field threw a bit of a curve ball…it included WIND in the calculation. STRYD and RunScribe don’t do that. Well, at least not yet.

STRYD apparently have had a plan to include it for a while.

Let’s put to one side that Garmin are using a dated, offline weather forecast to generate the wind component of their live power calculation and let’s put buildings to one side too. Garmin’s wind value might have some value on open land in relatively constant wind conditions over an extended duration.

Running Power AppsAnecdotally I know that my running pace drops when I run into the wind. I really don’t like it. There is that pesky, physical effect of the wind thrown in my face by physics and, in my case, there’s also a demotivating psychological effect from the conditions. I’m not quite sure how I ‘d quantify the latter but Mr Daniel’s had a go at quantifying the former:

Wind Calculator for running: http://runsmartproject.com/calculator/

So my first strategy is to run behind someone else. Drafting. When in a large race with lots of people or when running round a track in a confined space close to a few other runners then I’m not quite sure how the generic effect from a weather forecast’s wind would handle that.

As the wind speed increases, might the effect of drag from my clothes or drag from me being taller than you play a factor? Drag. Cyclists know that the drag effect gets worse the faster you go. The same principle applies for strong winds I would have thought – there will be another one of those pesky physics formulae there for that too somewhere.

Have a think about these points raised elsewhere by Coggan.

  1. The wind speed in the weather report is NOT measured at ground level and will be lower in reality than from the weather record.
  2. The actual energy required to overcome wind at the speed RUNNERS move is relatively small. There was a 1970s wind-tunnel/treadmill study done on this, no doubt wind has changed significantly since then in this digital age. 😉

Coggan (who comments further below) says we are talking about less than 5% impact on pace/energy cost, even for fairly strong winds. That’s a relatively small amount but it IS noticable…for you cyclists (or existing power runners!) then 250w would need to become over 260w to make similar progress in windier conditions (don’t forget drag and psychology)

 

Garmin Running Power Comparison – VO, GCT, Hills, Track, Snow, Dark, Stupidity

To be frank. I don’t really care about the details of the science behind it all. I just want to know what to do with the numbers.

My rule of thumb is to scientifically up the power ‘a bit‘. Up the power a bit when going uphill and, if I can, up the power a bit when going into the wind. In cycling an acceptable measure of variability, if trained for, might see your Normalized Power not exceed 5% of your average power.

You can use STRYD or RunScribe or Garmin Running Power and a bit of ‘paying attention’ to keep to that extra 5%ish. For extended periods of running into a headwind you might also, shock horror, use your heart rate too as a means of moderating effort.

It’s Here => Garmin Running Power – Is it any good?

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24 thoughts on “Garmin Running Power & Wind

  1. Efficiency also changes with temperature and air density, so there’s more data and ambiguity to come with this running power journey we’re going through.

  2. Ignoring the fact that Coggan switches sides the second he’s paid by a given company…

    5% cost is actually a crap-ton in a marathon scenario, and if we look at most numbers putting it closer to 10%, that’s huge too.

    A 5% increase in HR for example, at say a typical marathon HR for me of 160ish, would mean a bump to 167.5 – which is a totally different realm. A 10% increase in HR (effort) would be some 16bpm, up to 176, which is in 10K pacing territory (for me).

    For me, that’s the challenge I have with all these units: The one scenario where running power would be most useful is the one scenario it doesn’t work on: head winds.

      • And just to be helpful to others, and because I’m sure you’ll find ways to try and twist this 18 different ways as you always do, I’ll leave folks with this long thread that over the course of a couple years details your apparent change of heart:

        http://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Triathlon_Forum_F1/DCRainmaker_preview_of_Stryd_running_power_meter_P5421037-2/

        “I can’t see a running power meter having a significant impact on how people actually train and perform.”

        The5KRunner helpfully already quoted links above as to when you were for them. It’s unclear that you’re no longer paid by Stryd, if you’re now against them again.

        • Yup, and I still stand by everything I said in that thread, with one exception: I underestimated the utility of real-time power data as a pacing tool (probably in part because I started in endurance sports when I was young, and have always had a well-honed effort sense). Outside of that, as I have said elsewhere I think the other metrics Stryd provides are really more interesting.

          • BTW, although I no longer receive compensation from Stryd, I continue to consult with them periodically. I do it for the same reason that I initially approached them, i.e., for the intellectual stimulation provided by learning exploring new ideas and attempting to make them approachable by coaches and athletes. Given that my day job pays me quite handsomely and demands most of my time, it certainly isn’t because I am trying to make a living selling half-baked opinions to others.

        • Last comment: you haven’t addressed my comments about the magnitude of the effects of wind on runners, and how this enters in the question of attempting to measure power. Yet, that is what this blog entry is about…

          • I did above, you didn’t read it:

            “5% cost is actually a crap-ton in a marathon scenario, and if we look at most numbers putting it closer to 10%, that’s huge too.

            A 5% increase in HR for example, at say a typical marathon HR for me of 160ish, would mean a bump to 167.5 – which is a totally different realm. A 10% increase in HR (effort) would be some 16bpm, up to 176, which is in 10K pacing territory (for me).”

        • Thanks, those links were entertaining. Coggan you’re a puzzle to figure out. Leave alone having confused people world over with your first defintiion of FTP. Even reputed coaches if asked today have little clue what an FTP time duration really is. You’ve since backtracked on these definitions and still confuse more people. Repercussion? Scientifically minded people now refused to even address FTP because of the uncertainty around what it represents. The present Stryd loyalty mimics the FTP backtracking. One of the reasons I stayed away from buying the Stryd was after noting your rather disproportionate influence over what you think is running power. I People have been investigating this stuff since the 1930’s mate, we don’t need you as the patron saint of running power.

    • I guess 5% at any one instance in a race IS important. Will it be 5% over the entire race?

      eg

      The 2016 Cardif HM world champs was pretty windy http://www.cardiff2016.co.uk. Kamworor did 59:10, WR is 58:23. I could do some maths…if I knew the windspeed I could do some more.

      https://www.iaaf.org/results/iaaf-world-half-marathon-championships/2016/iaafcardiff-university-world-half-marathon-ch-5614/men/half-marathon/final/result#resultheader

      https://80runs.co.uk/2016/03/27/race-37-world-half-marathon-championships-cardiff-wales-26th-march-2016/ quotes “hurricane-like” wind. anecdotal. The IAAF report diplomatically put it as “But the conditions worsened in the final quarter with a strong wind and HORIZONTAL rain buffering the runners.”

      Regarding HR & %ages: A 5% increase in my HR at 90bpm is hardly noticable, a 5% increase in my HR at 190bpm would result in my imminent demise.

      • Garmin Connect already records this information. So it could be used as a modification to the % biomechanical efficiency that I presume all running power meters have within their algorithms. To my mind it’s not so different to the wind factor being discussed here – other than a greater level personal variation.

        ps. sorry for the duplicate post – I didn’t spot the “awaiting modification” and thought it was lost in the ether.

          • At risk of exposing my ignorance:

            Power=Force x distance. But this gives the theoretical MINIMUM power. The human body, like a car engine, is not 100% efficient. Stryd already “measures” leg stiffness as a means to adjust this biomechanical efficiency. Plus there are external factors that further reduce this efficiency, like wind, temp, altitude. So “Power Input” does not equal “Power Output”.

          • I avoided answering this, to avoid giving an incorrect answer.
            Have a look here: http://www.georgeron.com/2017/09/the-physics-of-running-power.html he will give you the exact answer you might need better than i can
            i seem to remember there are calculators there to enable an adjustment of power by altitude.

            does wind reduce internal efficiency? or does it reduce the resulting external speed?

            so i’m not sure that the inputs and outputs are quite the right way to envision it

          • Agreed. Mechanical power is mechanical power; factors that influence the physiological cost of generating said power are something else.

  3. 5KRunner ,

    Why does everything a certain ‘Coggan’ say suddenly have to be the only truth? I’d stay far from this guy. He’s a bully online , on several forums he trolls on, which tells me far more about his reputation that anything else. That he was against running power meters, got ‘bought’ over by Stryd and now consults for them tells me where his loyalty stands. Wind affects mechanical and physiological cost. Proven in the best papers and running books. Period. That Garmin is trying a fresh approach to account for a slice of the pie is not welcomed by Stryd. Coggan has been released into the wild to go bite at fresh thinking.

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