I'm not sure anyone understands running power including the manufacturers, the difference in power between stryd and Garmin shows it's a waste of money at this stage.

The difference in the numbers between the manufacturers is a little disconcerting. I have been running with stryd all year and I found that using run power as a secondary metric to HR at Ironman Chatt was actually kind of helpful. I used my data to set a power cap not to be exceeded even on the climbs.

I thought it helped me run a more consistent race. So for me there is some utility in it.

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https://www.strava.com/athletes/773280
http://imroycer81.blogspot.com/
teamemj.com
everymanjack.com

I feel like Strava's GAP formula matches my perceived exertion pretty well. I feel like if there was a real-time calculation for that, it would get the job done.

All you would need is pace/incline. Who cares how many "watts" you are running at. I want to run at X:XX pace and it seems lit it would be pretty easy to give that data even without a footpod.

But that wind thing is tricky..

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/kj

http://kjmcawesome.tumblr.com/

Agreed, pace normalized to as many other relevant factors as possible (definitely incline, but ideally also temperature, wind, etc.) would seem to be what's most useful.

I use grade-adjusted pace on my 920.

Got it from garmin iq

I still am intrested in running power though

I'd be curious to try to understand why running power appeals, what does it offer that improves on grade-adjusted pace (ideally also adjusted for other things, e.g. wind, temperature, etc.)? It seems like running power, whatever that is, would go up if you ran inefficiently and go down if you ran more efficiently, wouldn't that incentivize bad form? But I suppose I don't actually understand what running power actually is.

Stryd reports form power separately separately from productive power. This means that it would give you insights to bad form and inefficiencies. It is pretty cool.

The idea is that you can do structured training to power, and then race to power the same way you do it for biking. It is probably like GAP 3.0. It is another available metric, and it is fun.

I understand what you are saying but I think I would go about it like I do on my bike. The least power for the most speed.

I would like to try it out to see if the hype is really there. I however, am unwilling to pay the big price just to try it though.

Hi All,

Angus here. (Disclaimer: I am with Stryd)


Stryd is a more approachable normalized, graded pace in some ways. Our goal is to provide runners a single target they can follow on race day for success. This greatly simplifies race planning and delivers what we call "the ultimate racing experience".


Stryd measures your power and performance via metabolic costs. Our technology has been verified through university and laboratory studies. Please find one of these studies here: https://hetgeheimvanhardlopen.nl/...-14-test-runners.pdf


We agree. Power data is just a number at the end of the day. Your success is based on what you do with your wattage. We built our platform to help runners discover new insights on training and recovery to peak for race day. Then, we give them a power number to follow so they can get a new PR by avoiding the "wall" on race day. This is the "ultimate racing experience" we strive to deliver to athletes.

If you are interested to see how Stryd helps runners, please check out our Watts That Won series at https://blog.stryd.com/

Please ask me any questions on your mind!

"I would like to try it out to see if the hype is really there. I however, am unwilling to pay the big price just to try it though. "

Looks like all you need is an HRM strap or the new Running Dynamics Pod. Not sure how much that would cost (too lazy to look) but I assume way less than the $199 that Stryd is offering.

I've been using a stryd for 2 weeks now. Right now for me, the biggest benefit is the accuracy of distance/pace compared to GPS or a standard footpod. I didn't even have to calibrate the stryd. No more dead spots or lagging of pace when running outside. I'm now using the stryd as my pace/distance calculator on all of my runs (treadmill and outside). GPS is still turned on but it's not being used for pace/distance.

What I don't know is if the running dynamics pod will double as a footpod like the stryd or if you still need to use the standard garmin footpod.

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blog

Unfortunately I have a 920xt and not the 735/935 or Fenix 5 models that the pod is compatible with :(

I know nothing about the Garmin power pod, but my Stryd has been a phenomenal tool that has helped me continue to improve my run for the past year. It is consistent and has been a great training and racing tool. Very strange the Garmin reports such high numbers.

You seem to be overlooking the somewhat significant requirement of one of Garmin's brand new watches.

I can't afford to upgrade my power meter, bike computer and watch every single year so I'm going to stick this one on the backburner.

How could the Stryd possibly be more accurate for distance than GPS? GPS isn't great an instantaneous pace, so cadence from a footpod can be more accurate there. But over any actual distance, your stride length would have to be insanely consistent for a device that lacked GPS to accurately capture the distance covered. Or am I missing something?

Read this...

http://fellrnr.com/wiki/Stryd

edit: and this.... http://fellrnr.com/wiki/GPS_Accuracy

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The mega benefit to me is instantaneous pace. There is an option in the Garmin watch to show real-time pace from the foot pod rather than GPS. (It still uses GPS for all other distance measures.) With that setting and a Stryd, real-time pace is freakin' awesome. I would get a Stryd again just for this improvement alone.

Yeah, I've thought about getting a footpod just for better instantaneous pace. I suppose a Garmin footpod or Stryd are basically interchangeable for that purpose, since all that's being measured is cadence.

Huh, "My testing has shown that the Stryd is stunningly accurate in its measurement of distance... far more accurate than any GPS device I've tested." How could a footpod with accelerometers in it possibly be more accurate that GPS over long distances, i.e. many miles? That kind of blows my mind. Heck, my mind would be blown if the footpod even managed to get close to GPS results, but apparently it's far superior.

Yeah, I have read that guy's reviews and his analyses, and I think something is seriously wrong with his protocol. A lot of his results simply make no sense. For example, he has most GPS watches at relatively low precision, but I have hundreds of miles on multiple watches that prove the opposite. And, he used to show the Apple Watch (it is gone now from his chart) as both precise and true. Again, I have dozens of activities that prove otherwise. He still has the iPhone 5 on the chart as relatively true and precise; that is crap. My Garmin devices have a standard deviation of about 0.02 miles on a 5.07 mile route. An Apple product (watch or iPhone) has a SD of around 0.1 miles on the same route. There is something very wrong with how he is capturing and analyzing data.
I am not sure... it is probably worth a question to Stryd. The Stryd is capable of delivering instantaneous pace to the watch that is derived directly from the accelerometer, not just cadence. So, if the watch displays that instantaneous pace, rather than its own calculation based on cadence, then the Stryd would be better.

Cadence can be provided just from the accelerometers in the watch. Pace is cadence and stride length dependent so Stryd / footpod are bringing other things to the table other than just cadence.

Oh, I totally understand why the Stryd would be better at instantaneous pace.

But the idea that it's better at precisely measuring the distance of a ~20-mile run kind of blows my mind.

I'm quite pissed that they are not bringing this into the Fenix 3 Sapphire; watch was fucking expensive and the only reason they aren't doing it is because the didn't update the Connect IQ platform on it.

There is no way. The poster also notes "dead spots" unless running through the Canyons of Utah, there are not dead spots with GPS. Even now with accelerometers and GLONASS, places like NYC and Chicago are not a problem. I am with you, cannot understand that premise.

I've never had an issue with gps for distance. I regularly run an out and back course, and although instant pace is patchy, If I turn back after 4 miles say, my watch will log 8 pretty much within a couple of feet from where I set of. I've had the same experience with pretty much any Garmin I've tried, starting with the 305, then 620, 910xt and now Fenix 3.

I know people complain about accuracy, but I've never had an issue where I live.

After 11 months with the pod I'd completely forgotten how poor non-Stryd instantaneous pace was.

Can you explain how this data shows the accuracy of the Stryd compared to VO2?
From what I see in the graph a VO2 of 45 can give a Watts estimate between 2.9 and 3.8 w/kg at 55 it goes from 3.5 to 5.1. That is pretty large variability.
Does Stryd take into consideration RE somehow to make it more accurate?

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Tiago
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Sponsors: : Blueseventy :

You work for Stryd and offered to answer questions, so, a really basic one. How is it logically possible that Stryd could offer highly accurate measurements of distance covered? For the sake of an example, how could a Stryd unit, with its associated sensors and algorithm, be extremely accurate in measuring the distance of a marathon-length run?

Disclaimer: I am with Stryd


Hi niccolo,

Thanks for your post. This is one of our breakthroughs. Stryd has extremely fine grained spatial and temporal motion tracking. This allows us to get highly accurate speed and distance without calibration. We track the whole motion of every stride during your run. Please see http://fellrnr.com/wiki/GPS_Accuracy for details surrounding Stryd's accuracy.


We are compatible with the Fenix 3 Sapphire and are dedicated to supporting as many watches as possible. Let me know if you are interested in trying out running power.


The paper jumps into an explanation of this right after the 'The Stryd data are just as good as the VO2" graph.

The authors dissect the following factors: metabolic efficiency (paper here), energy cost of running (paper here), and running economy (paper here). If anyone is interested in reading more, Ron's and Han's complete works can be found here.

Best,
Angus

So basically you're saying that the sensors in the Stryd allow it to so precisely track spatial dynamics that it can differentiate between, say, a 99, a 100 cm, or a 101 cm stride length. So the Stryd is literally measuring every step a runner takes, so precisely that all those steps add up to the total run distance significantly more precisely than the best consumer GPS tracker available would report. Honestly, if it weren't for the fellrnr.com data you mentioned (with which I was at least somewhat familiar and which seems credible), I would tell you that you were smoking something. I'm still struggling to wrap my brain around this...

It's really not that hard to fathom, this is how all footpods have been working like this for years not just Stryd.

They don't simply measure cadence and multiply that by a fixed stride length for your entire run. They utilise the accelerometers in the footpod to measure foot swing force and effectively use this as a dynamic calibration factor for measuring distance that can (to a certain degree) compensate for changes in gait.

As someone else posted above, if it was simply a case of multiplying cadence by a fixed stride length then the Garmin models with wrist based cadence would do just as good a job at measuring pace and they really don't.

I routinely use a footpod and just GPS for about 50% each for my runs and whilst the distance is usually +/- <1%, the major benefit of the footpod is more accurate instantaneous pace. And this is a Garmin footpod, not Stryd.

It's really not that revolutionary, you should join us in the 21st century :)

Revolutionary or not, I had no idea you could so precisely infer distance covered just from accelerometer data. Now I'm trying to wrap my head around whether this is unique to running or whether you could make similarly precise inferences in other activities (something like hiking presumably yes, swimming I'm not so sure).

It is basically inertial navigation, used in everything from subs to airplanes to missiles to spacecraft. The biggest issue with inertial navigation is drift, the longer you are using it, the longer your uncertainty in your position. All those little errors in acceleration and vector add up over time, resulting on your velocity and position being in correct. Fancier systems have less drift, but running a marathon requires only takes ~4 hours compared to a submarine that is under water for days traveling hundreds of miles under the polar ice caps. Due to drift all those platforms zero their position using another system like GPS or star position to negate their drift. I assume stryder is also using gyroscopes in addition to accelerometers.

In other words it can be used in every sport.

He's speaking from a trail running perspective. Heavy tree canopy coverage plays havoc with GPS reception. Depending on the time of year (ie, are there leaves on the trees), you can see swings of 15-30 seconds per mile. The signal drops--and then doesn't reacquire--then straightlines your 'path' instead of tracking all of the mileage. Plus--with the GPS only having so much resolution (it's what, accurate to within 3-5 meters these days?) a twisty path gets even more straightlined. I train on trails, have a Fenix 3 + footpod and recalibrate it every so often.

I don't think that's right. His baseline testing is on open roads, and the Stryd crushed the best available consumer GPS watch. As an additional test he subsequently tested it on trails. I don't have time to go back and look up the specifics, but I remember thinking the same thing you did, and then correcting myself after I looked back at the site.

Gotcha--however, he still puts the footnote down that he's testing on curvy roads---and he's ignoring data during the winter months with no leaves on the trees.

I've been running with Stryd since May and can vouch for fellrnr's findings. I've observed the same accuracy and repeatability with the foot pod that most people are seeing. I also run at a college track a couple of times a month to verify that Stryd is measuring good distances and look at the raw data over 10+ laps. Not every single Stryd user has had this experience, though, and some users do require some sort of calibration factor before using it for training, but from reading their forum and Facebook page, most users are seeing great accuracy and precision.

You have to kind of understand the underlying tech of GPS to know that it's inherently VERY inaccurate, especially for cheap consumer devices, GPS watches included. A GPS is estimating your location based on signals from satellites over 12,000 miles away. You have to spend several thousand dollars on a survey-quality GPS for reliable 1-meter accuracy. The foot pod is measuring your foot's movement, on your foot, and likely sampling the 9-axes of motion (translation, rotation, magnetic orientation) several times a second. If you research Arduino and the crazy amount of DIY sensors you can buy, you'll see how accurate cheap sensors can be at home. Now imagine how good the data can be when you have high quality sensors and an engineering team hard at work refining the device.

My data from a recent training run:
Lap, Distance, % Error - 400m
Lap 1: 402.2, 0.55
Lap 2: 401.9, 0.48
Lap 3: 405.6*, 1.40 - passed a couple walking on the inside lane
Lap 4: 401.2, 0.30
Lap 5: 403.4, 0.85
Lap 6: 400.8, 0.20

Power estimates and cost aside, it's really a reliable device. I have more than two decades of being a tech hobbyist and now an engineer who uses tech at work, and I think Stryd is a very unique device with a fantastic support team behind it. Other manufacturers should strive to provide the same or better trueness and repeatable performance, because it should matter to everyone who doesn't run on a track to collect the best data they can. Why not, right?

I think the root problem with his protocol, is that he has known 1/4 mile markers on a test route. He counts each 1/4 individually as a data point. He does not say whether he has multiple runs with a device on that route, or if he just does one run per device. I suspect that GPS tends to correct and refine itself over the course of an entire run. So, let's say a device shows 0.23 at the first quarter and 0.50 at the 2nd quarter. In that case, the first data point would be 0.23 and the 2nd data point for 0.27. So, on paper it looks really bad, but is accurate for the total distance. By contrast, say a pod or another device shows 0.24 on the first mile and 0.48 on the 2nd mile. In that case, it would appear more accurate, yet be less accurate overall. I suspect that is why pods show more accurate to him than GPS devices. My GPS devices have a very high degree of trueness and precision for total runs, where iPhones and pods are rather crappy.

There may be some problems with his protocol, but he seems very rigorous with his testing. There are lots of us who can claim the same results with our Stryds, though, and some of us are just as rigorous with our testing. Your example showing 0.24 for the first mile and 0.48 for the second mile would be for an uncalibrated Stryd. Once calibrated, realistically, it would be something like 0.246 miles and 0.255 miles to equal 0.501 miles. See my example above.

But you are mistaken that a GPS device refines anything during your run. It reads signals and triangulates your location with some degree of precision, and any accuracy you see would be a byproduct of cancelling errors, not true precision. Can GPS accurate over longer distances? Sure. Can you have a really repeatable GPS? Of course. I use survey-quality GPS at work with 10-cm resolution, and it's pretty great, but my fenix3, cell phone, and eTrex can't come close to that level of precision. And to get 10-cm, my system needs two GPS units, one as a base over a known benchmark (and 10+ minutes for DOP to settle), and one as a rover to communicate with the base. I'd do a test run to compare the survey GPS with Stryd, but I haven't figured out how to run with the antennae yet.

Can I ask how you can claim to know your GPS device has a very high degree of trueness and precision? In what conditions? How do you know? What data do you have? How have you measured and verified your distances? I collect and use data for a living, so I am always curious of people's test methods for verifying that their devices are performing correctly.

The point that I was trying to make is that every individual GPS data point has a margin of error. However, over the course of a run, it will collect a crapton of readings. The net is likely a very accurate overall distance, though internal distances between data points could vary more. I believe that I am seeing this in the statistical analysis I have done with my devices on my routes (and confirmed by two friends who have different devices on the same route).
I can speak to precision, but not trueness. I have hundreds of runs on a routine course I have done for over a decade and using multiple GPS devices. The mean distance is 5.07 miles with a standard deviation of 0.02 miles. All of the GPS watches have had the same results. Maybe one of the older watches was a hundredth of a mile different SD, but I cannot remember without recalculating. By contrast, I have dozens of data points with an Apple Watch and iPhone over the same route. The mean was 5.06, if I remember correctly, but the SD was 0.1 miles. I only have dozens of Apple data points, because it was apparent pretty quickly that they suck, and I quit using them for runs.

Given the volume of devices with the exact same (or very close) mean, I trust the trueness of these in general. But there is no way that I it is worthwhile to go out and measure it to the inch.

In summary, GPS devices = awesome precision; AW & iPhone = mediocre precision. I have not done any analytics with pods, but I have no doubt that a calibrated pod would return good results, but only so much as your gate is unchanged (Stryd excluded).

Angus, any chance Stryd will soon figure out how to make the footpod work with the Garmin 5s?

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just your average age grouper . no one special . no scientific knowledge . just having fun.

In running there is an added factor that you know that 80ish times per minute, the foot becomes motionless for a fraction of a second, and you also know when that occurs.


I'm amazed that other folks are amazed at this, the first running watch I had with speed and distance was (I think) the freestyle fs-1, it used a footpod, and used what would later become ant+. That was 2002, there were other watches that worked the same way, I am reasonably confident that the nike elite triax was one.

The garmin forerunner 301 came out in 2003 and was less accurate than the freestyle watch.

This is the basis for inertial navigation systems, used for decades in ships, submarines, airplanes, and spacecraft. See https://en.wikipedia.org/...al_navigation_system. It's a pretty well-understood technology and can be surprisingly precise if you have good sensors.

That's an interesting point. Tho I think of how I use my PM on the bike. I'm looking for a drop in power to correlate with an increase in speed, or hold a particular output for a prolonged duration, etc. I imagine it would be the same for running: power would simply indicate performance in a particular context.

l'm still rocking a FR910xt so I'm not using Garmin's running dynamics and I don't have a Stryd pod. So I have no idea what level of analysis they provide. But, at the very least, if you layered power into metrics such as pace, HR, incline, etc., wouldn't you be able to see the correlation between power and overall efficiency?

Full disclosure: I too know next to nothing about run power.

EDIT: Apologies. Should've continued reading thru the thread. Looks like folks far more capable than me have cleared this up. No more posts till caffeine has kicked in.

Hi way2sloow,

Stryd is technically compatible. However, we do not currently recommend the Fenix 5S. There are widespread reports of ANT+ dropouts when using Garmin heart rate monitors, Garmin power meters, Garmin run dynamic pods, and 3rd party sensors that make the experience unusable.

Garmin has essentially stated that there are issues on the Fenix 5 and Fenix 5S that will only be fixed with new hardware.



If anyone ever has any issues with Stryd, please email us at support@stryd.com and we will take care of you.

Best,
Angus