Any "Running Power" Skeptics Converted After Trying It?

I have used Stryd on and off for the past year as others have commented it is useful for calibrating effort on hills. I was shocked when I saw how much more effort - "Power" it took to go up hills vs the flat. After I compared it to the number of gear changes I did on a bike going up hills it began to make sense. Stryd provides a a lot of different numbers LSS (leg Stiffness), Form Power, GCT (Ground contact time) not useful for me.

All of these metrics depend on pace - the faster your pace the less GCT, and the % of form power declines.

I understand that lower GCT and higher LSS and form power is desirable however there doesn't seem to be any consistent way to improve any of the metrics in a way that is measurable since they are so dependent on pace.

I have tried to measure the effect of deliberate form changes while using stryd - and it doesn't have the precision to pull out that level of detail. I also tried to to discern the effect of different shoes but again it doesn't have that level of precision.

I would use Stryd to run a race with hills - like Boston but on a flat course it wouldnt teell you anything that pace wouldn't tell you

Its other useful metric is metric called Critical Power (CP) which is Stryds version of FTP (Functional Threshold Power) the definitions of which are less then precise but can be thought of as the pace you could hold for an hour.

If you can compare CP from different phases of your training than you can understand if you are improving or not. Of course you can just run a time trail and garner the same information

In summary Stryd is very useful for calibrating effort on hills and may be useful for people who can make use of the many metrics it can produce.

I have stopped using it for my everyday runs although I might start using it whenever I start a training for a race.

For those interested in a deeper dive I recommend the book "The Secret of Running" by Hans Van Dijk and Ron Van Megen which has a thorough description of power meters with a specific focus on Stryd

I mean, it's kinda true. If you don't see the math, it can feel like guessing. Either way, you're relying on the transforms of whoever they used for the calibration, not your exact numbers...

"But on hills, the relationship between mechanical power and energy consumption breaks down—so they reverse engineer it.

During the device’s development, they tested runners on inclined treadmills while wearing Stryd units, measured their oxygen and carbon dioxide consumption to calculate energy expenditure, and used that data to adjust their algorithm to give the “right” answers. So, on flat ground, they measured power (200 watts, say) and noted that this corresponded to a given rate of metabolic energy consumption (1,000 watts, say). On the inclined treadmill, they cranked up the speed and angle until the metabolic energy consumption was 1,000 watts, and then, for consistency, programmed the algorithm to call that power 200 watts.

From a scientific perspective, this means the number your running power meter spits out is essentially meaningless. "

Stryder Return on the King wrote:

Can anyone here answer whether something like the Stryd foot pod can be useful for this concept.

Running a certain pace and changing your form in a certain way (cadence, stride length etc) to make that same pace happen with a smaller effort (in this case, power output). I guess one can do this with HR to a degree but I’ve never found a consistent reliable way to do so as my HR is all over the place on different days at the same pace even with a chest strap.

It would be interesting to repeat reps of a certain distance in a certain time and try to lower the power consumption.

Stryd says it can, I've seen a white paper from them for how to set up the spreadsheets, but note the Alex Hutchinson article I referenced above under the section 'Case Study'. At least in that group of trained athletes trying to change cadence, Stryd universally said higher cadence was more efficient, whereas the actual respiratory test found that to not be the case. Sort of goes back to the non-linear transforms and smoothing algorithm questions. Since it's not a direct measurement it can be tricked.

Folks are saying it can be useful data sometimes, but it seems black box enough that it would be hard to decide when it's useful and when it's leading you astray?

You should not exclusively run by HR or "Power" but both.

Depending on your fitness state, your heart can be rested and responding well while your legs are trashed. Or visa-versa.

Heart is a completely different creature than the muscles in your legs.

If you follow your Stryd numbers over time you'll learn the patterns.

I've actually turned off all fields on my watch except HR and Watts, I don't use pace anymore, just follow what my body is telling me and look at it afterwards.

But Stryd is actually too expensive for what it is though. $220 is more than a watch and it's way less tech than a watch. They say the Coros Pace 2 matches Stryd numbers except in wind, so you basically are getting a full watch with power numbers for the price of Stryd. Once Garmin starts selling a Stryd competitor the prices will become half of what they are now and there will be wider adoption.

Stryd is just a business targeting recreational runners.

Most people benefit more by running further and faster. It is that simple.

Stryd won't give you a PB that you can't achieve by pace alone.

slomo wrote:

I've actually turned off all fields on my watch except HR and Watts, I don't use pace anymore, just follow what my body is telling me and look at it afterwards.

And how has that materially changed your running over time? Less down time? Fewer injuries? Faster daily pace? Ability to increase total volume? Better ability to lock in on how different efforts should feel? Faster recovery?

Or it just feels more purposeful?

Your Coros comment is interesting, because I was actually curious about Polar's wrist system. They aren't even pretending to measure leg power like stryd. It's pace, barometer, and weight based, which seems even more closely linked to grade adjusted pace than Stryd. I dunno.

Pace is king wrote:

Stryd is just a business targeting recreational runners.

Most people benefit more by running further and faster. It is that simple.

Stryd won't give you a PB that you can't achieve by pace alone.

I've noticed the target market of buyers for Stryd seems to be triathletes, who look for tech to throw at cycling and swim for 'incremental gains' so are conditioned psychologically to do the same for running. It may indeed provide that but it's definitely not the only way, it's just one that fits with a certain mindset, one we used to couch as "paralysis by analysis."

I've had my stryd pod for about a year and a half now.

I'll echo others and say that the power function isn't all that useful, except hills. I did use it in my half-ironman in 2019 to pace a longer 1/3 mile hill we did twice during the race, helping to not completely kill my legs 4 hours into the race. I've also used it to help sort of judge effort on hill workouts and trail runs where pace becomes a lot harder to judge. I don't live by that power number (because some things like loose footing on the trail can totally mess with your overall effort), but they are at least somewhat useful to determine if I should push harder or not.

What I really bought it for was accuracy on the treadmill -- and it's damn accurate. Once calibrated (using the track method), I've done outdoor workouts using just the pod and I'm within a few meters each time. On the treadmill, that means that I just go by the watch pace and can completely ignore what the treadmill says. I found this to be invaluable when going from treadmill to treadmill in the winter and have discovered some treadmills have a variance of 20+ seconds/mile.

Hey do you want a Garmin foot pod? I was looking through old stuff to get rid of and found one. I have no use for a footpod anymore. Seriously, I will ship it to you.

Pace is king wrote:

Stryd is just a business targeting recreational runners.

I know at least 2 world marathon major winners who use Stryd, and they both bought it themselves.

Which means nothing to anyone reading this.