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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:
davearm wrote:
Andrew Coggan wrote:
I can't see a running power meter having a significant impact on how people actually train and perform.


In an IM race, I know...

I should target a NP of 68-70% of my FTP
I should target a VI of around 1.05
I should keep MaxP ~ FTP

Intuitively, all of these same concepts of optimal average and maximum power production, and variance, seem like they would apply to running as well.

Specifically, it would stand to reason that a robust running power meter would answer the question of how fast an IM racer should run up a hill, just as a power meter already does for the same athlete on his bike. Since there is an optimal power output when climbing a hill on the bike course, surely there is a corollary for climbing a hill on the run course.

Given that, I don't at all understand why you don't see value in a device that would provide athletes the same data on the run as they use (often to the exclusion of all else) on the bike. Naturally the target ranges would need to be recalibrated for running, but the underlying principles would be the same -- average X watts, don't exceed Y watts. Why don't you see that as an improvement on things like pace, HR, RPE?


Because there's nothing a runner could accomplish using a powermeter that couldn't already be accomplished using a measured distance, a watch, and some common sense.


Is this still your opinion?

http://club.stryd.com/...n-flat-vs-hilly/1175

You seem to have changed your mind.
Last edited by: Trev: Dec 20, 15 2:27
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Re: DCRainmaker preview of Stryd running power meter [Trev] [ In reply to ]
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Yikes! And he actually used the word "shill"......
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Re: DCRainmaker preview of Stryd running power meter [Trev] [ In reply to ]
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Trev wrote:
Andrew Coggan wrote:
davearm wrote:
Andrew Coggan wrote:
I can't see a running power meter having a significant impact on how people actually train and perform.


In an IM race, I know...

I should target a NP of 68-70% of my FTP
I should target a VI of around 1.05
I should keep MaxP ~ FTP

Intuitively, all of these same concepts of optimal average and maximum power production, and variance, seem like they would apply to running as well.

Specifically, it would stand to reason that a robust running power meter would answer the question of how fast an IM racer should run up a hill, just as a power meter already does for the same athlete on his bike. Since there is an optimal power output when climbing a hill on the bike course, surely there is a corollary for climbing a hill on the run course.

Given that, I don't at all understand why you don't see value in a device that would provide athletes the same data on the run as they use (often to the exclusion of all else) on the bike. Naturally the target ranges would need to be recalibrated for running, but the underlying principles would be the same -- average X watts, don't exceed Y watts. Why don't you see that as an improvement on things like pace, HR, RPE?


Because there's nothing a runner could accomplish using a powermeter that couldn't already be accomplished using a measured distance, a watch, and some common sense.


Is this still your opinion?

http://club.stryd.com/...n-flat-vs-hilly/1175

You seem to have changed your mind.

Let's just say that:

1) I like Li's and Robert's vision; and

2) it's going to take more than just common sense to take maximum advantage of the data that the Stryd can provide. Fortunately, some of us have more than just common sense at their disposal:


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Re: DCRainmaker preview of Stryd running power meter [lightheir] [ In reply to ]
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lightheir wrote:
I 100% guarantee that if someone indeed developed a running powermeter that was every bit as accurate and precise as cycling powermeters, it would be a complete game changer at all levels for training and racing, just as it was for cycling. And you'd surely see some new and very useful metrics be developed.

Speaking of precision:



(From http://club.stryd.com/...wer-in-children/1330)
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Does the Stryd device give precise values under varying wind conditions and surfaces?
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:
Trev wrote:
Andrew Coggan wrote:
davearm wrote:
Andrew Coggan wrote:
I can't see a running power meter having a significant impact on how people actually train and perform.


In an IM race, I know...

I should target a NP of 68-70% of my FTP
I should target a VI of around 1.05
I should keep MaxP ~ FTP

Intuitively, all of these same concepts of optimal average and maximum power production, and variance, seem like they would apply to running as well.

Specifically, it would stand to reason that a robust running power meter would answer the question of how fast an IM racer should run up a hill, just as a power meter already does for the same athlete on his bike. Since there is an optimal power output when climbing a hill on the bike course, surely there is a corollary for climbing a hill on the run course.

Given that, I don't at all understand why you don't see value in a device that would provide athletes the same data on the run as they use (often to the exclusion of all else) on the bike. Naturally the target ranges would need to be recalibrated for running, but the underlying principles would be the same -- average X watts, don't exceed Y watts. Why don't you see that as an improvement on things like pace, HR, RPE?


Because there's nothing a runner could accomplish using a powermeter that couldn't already be accomplished using a measured distance, a watch, and some common sense.


Is this still your opinion?

http://club.stryd.com/...n-flat-vs-hilly/1175

You seem to have changed your mind.


Let's just say that:

1) I like Li's and Robert's vision; and

2) it's going to take more than just common sense to take maximum advantage of the data that the Stryd can provide. Fortunately, some of us have more than just common sense at their disposal:



Let's just say that you changed your mind.

Do you still agree with the following comments you made earlier in this thread?


Andrew Coggan wrote:

"I can't see a running power meter having a significant impact on how people actually train and perform.

Because there's nothing a runner could accomplish using a powermeter that couldn't already be accomplished using a measured distance, a watch, and some common sense.


Second, ask youself this: are novice runners who can't pace themselves well based on perceived exertion going to benefit more from learning how to do just that, or relying on a device that only provides a crude estimate of the metabolic demands?*

*Note that an important difference between running and cycling is that the economy of movement is much more variable in the former than in the latter. Also, muscle use varies more in the former than in the latter, e.g., even if you keep your estimated power constant when transitioning from the flats to up hill, you will be placing more demand on your quads as a result. So, should you really be aiming for an iso-power effort, or an iso-metabolic one?

Finally, note that entire argument in favor of a running powermeter has now seemingly been reduced to a single application, i.e., as a pacing aid when running in hilly terrain. "Game-changing" indeed...



Not a radical departure in the least.

Consider, for example, the possibility of pacing by power...despite exploring the idea of calculating a theoretically-optimal strategy based on the physics and physiology of cycling long before, e.g., bestbikesplit.com, my advice to people on this matter has always been to simply use their powermeter to make sure they "don't go out too hard".

Similarly, a couple of my PPPs have always been:

"If you know your power, then at best knowing your heart rate is redundant, but at worst it is misleading"

and

"If it feels hard, then it is hard"

with the point being that along side power (pace for a runner), perceived exertion is a highly valuable tool.

On a constant grade, the metabolic cost of running is directly proportional to speed from ~4 mph up to as fast as you can run for several minutes (hard to say beyond that point, as a steady-state in VO2 won't be achieved, and biomechanical estimates of power output are just that, i.e., estimates).

There is some drift over time/effect of fatigue, but it's really only large at supra-threshold intensities (same is true for cycling). One study in J Appl Physiol that I recall, for example, had ultra marathoners running on a treadmill for ~5 h, allowing them to adjust the pace as they desire. VO2 stayed essentially constant over time, as they slowed down by (IIRC) 8% (implying that if they hadn't slowed down, VO2 would have risen by about the same amount).

A 1% increase in grade typically results in a 4% increase in metabolic demand. As I mentioned before, though, there is also a significant shift in muscle use (e.g., see Costill's classic study of glycogen utilization in the gastroc vs. v. laterals), something that wouldn't be captured by a running pwoermeter.



Sounds like what you'd really like to able to measure are things like stride length, contact time, flight time, etc., not power.


I advocate that all endurance athletes calibrate their perceived exertion against a reasonable surrogate for their metabolic rate, especially when the latter is also an absolute reflection/critical determinant of their actual performance ability. So, pace for runners, but power for cyclists.

thoughts...

Knowledge of a person's actual power output while cycling is immensely valuable, because:

1) mechanical power is what moves the bike down the road, and

2) cycling economy/efficiency does not vary dramatically between individuals, such that power provides a reasonable proxy for actual metabolic demand.

With that in mind, consider a running power estimator, i.e., one that relies on GPS, acceleromters, etc., to calculate power:

1) since power is being determined indirectly, the reported values provide no further insight into someone's actual performance than does knowledge of their pace and changes in elevation (although if accurate, estimated power does have the benefit of pinning a single number on things), and

2) running economy varies much more between individuals than does cycling economy/efficiency, such that the calculated power may not provide a valid/reliable indication of actual metabolic demand.

Combining the above with the fact that runners don't generally have to be able to rapidly change pace the way cyclists do, that they aren't as influenced by environmental conditions (e.g., wind), that they tend to utilize flat surfaces (tracks) for structured training, etc., and I can't see a running power meter having a significant impact on how people actually train and perform. "

What has brought about such a volte-face?
Last edited by: Trev: Dec 20, 15 15:23
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Ohh. o.k., got it.
Just wondering if you can write that with a straight face, as I clearly remember you ridiculing others for that exact point of view....




Andrew Coggan wrote:
davearm wrote:
Andrew Coggan wrote:
davearm wrote:
It's crazy to me that you think perceived exertion is the best solution to the running scenario, given what a radical departure it is from your position on cycling.


Not a radical departure in the least.

Consider, for example, the possibility of pacing by power...despite exploring the idea of calculating a theoretically-optimal strategy based on the physics and physiology of cycling long before, e.g., bestbikesplit.com, my advice to people on this matter has always been to simply use their powermeter to make sure they "don't go out too hard".

Similarly, a couple of my PPPs have always been:

"If you know your power, then at best knowing your heart rate is redundant, but at worst it is misleading"

and

"If it feels hard, then it is hard"

with the point being that along side power (pace for a runner), perceived exertion is a highly valuable tool.


The radical departure I was alluding to is that training and racing with a powermeter is quantified, precise, accurate, and backed by loads of science.

Perceived exertion is basically the opposite of all these things.

So you can imagine how odd it seems when the same expert advocates one approach for one discipline, and the complete opposite approach for the other.


I advocate that all endurance athletes calibrate their perceived exertion against a reasonable surrogate for their metabolic rate, especially when the latter is also an absolute reflection/critical determinant of their actual performance ability. So, pace for runners, but power for cyclists.
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:


2) it's going to take more than just common sense to take maximum advantage of the data that the Stryd can provide. Fortunately, some of us have more than just common sense at their disposal:


You're still in a logical trap with your quote. It clearly asserts that common sense is a sufficient condition to accomplish everything that's possible, with or without a powermeter.

Post shill transition, you want want this instead:

Quote:
Because there's something a smart runner could accomplish using a powermeter that couldn't already be accomplished using a measured distance, a watch, and some common sense.
Last edited by: trail: Dec 20, 15 18:17
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Re: DCRainmaker preview of Stryd running power meter [Nick B] [ In reply to ]
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Nick B wrote:
Does the Stryd device give precise values under varying wind conditions and surfaces?

No. Or rather, not yet.


-
My tiny little slice of the internets: dcrainmaker.com
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Re: DCRainmaker preview of Stryd running power meter [windschatten] [ In reply to ]
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windschatten wrote:
Ohh. o.k., got it.
Just wondering if you can write that with a straight face, as I clearly remember you ridiculing others for that exact point of view....

Disagreeing with others is not ridiculing them.
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Post deleted by Andrew Coggan [ In reply to ]
Re: DCRainmaker preview of Stryd running power meter [dcrainmaker] [ In reply to ]
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dcrainmaker wrote:
Nick B wrote:
Does the Stryd device give precise values under varying wind conditions and surfaces?

No. Or rather, not yet.

I don't think that can be said. The only way to truly test the precision under different conditions would be to repeatedly test under different conditions. Given the data I presented and how power is being determined, though, you'd expect the precision to be comparable regardless of the wind or surface conditions (i.e., a device on your chest measuring acceleration is agnostic as to why your center-of-mass is speeding up or slowing down).
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Re: DCRainmaker preview of Stryd running power meter [trail] [ In reply to ]
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trail wrote:
Andrew Coggan wrote:


2) it's going to take more than just common sense to take maximum advantage of the data that the Stryd can provide. Fortunately, some of us have more than just common sense at their disposal:


You're still in a logical trap with your quote. It clearly asserts that common sense is a sufficient condition to accomplish everything that's possible, with or without a powermeter.

Accomplishing the things I see possible is also going to take knowing more than just power.

Spring constants, anyone?
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:
dcrainmaker wrote:
Nick B wrote:
Does the Stryd device give precise values under varying wind conditions and surfaces?


No. Or rather, not yet.


I don't think that can be said. The only way to truly test the precision under different conditions would be to repeatedly test under different conditions. Given the data I presented and how power is being determined, though, you'd expect the precision to be comparable regardless of the wind or surface conditions (i.e., a device on your chest measuring acceleration is agnostic as to why your center-of-mass is speeding up or slowing down).

In this case, this was after spending an hour discussing it with their full team on a conference call a few weeks ago. They readily admit they don't deal with wind today, nor have a specific plan for how to do so.

Same goes for surface conditions.

(Side note: There are super-easy tests for both of these, running with a parachute vs not, and running on a path next to a beach vs not.)


-
My tiny little slice of the internets: dcrainmaker.com
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:
trail wrote:
Andrew Coggan wrote:


2) it's going to take more than just common sense to take maximum advantage of the data that the Stryd can provide. Fortunately, some of us have more than just common sense at their disposal:


You're still in a logical trap with your quote. It clearly asserts that common sense is a sufficient condition to accomplish everything that's possible, with or without a powermeter.


Accomplishing the things I see possible is also going to take knowing more than just power.

Spring constants, anyone?


If this device cannot account for wind or other horizontal drag factors, is it really a power meter?

Granted, under most conditions it would not matter, but having run directly up and downwind at the Surfside Beach half marathon ( you are likely familiar with area & potential conditions) I know it is possible to have pace varied as much as 1 min/mile by wind with similar effort.
Last edited by: J_R: Dec 21, 15 6:25
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:
Speaking of precision:



(From http://club.stryd.com/...wer-in-children/1330)

Do you have data for different treadmill inclinations?

Ale Martinez
www.amtriathlon.com
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Hahaha, I'm disappointed you deleted your reply! I thought it was entirely appropriate...
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Re: DCRainmaker preview of Stryd running power meter [dcrainmaker] [ In reply to ]
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dcrainmaker wrote:
Andrew Coggan wrote:
dcrainmaker wrote:
Nick B wrote:
Does the Stryd device give precise values under varying wind conditions and surfaces?


No. Or rather, not yet.


I don't think that can be said. The only way to truly test the precision under different conditions would be to repeatedly test under different conditions. Given the data I presented and how power is being determined, though, you'd expect the precision to be comparable regardless of the wind or surface conditions (i.e., a device on your chest measuring acceleration is agnostic as to why your center-of-mass is speeding up or slowing down).

In this case, this was after spending an hour discussing it with their full team on a conference call a few weeks ago. They readily admit they don't deal with wind today, nor have a specific plan for how to do so.

Same goes for surface conditions.

(Side note: There are super-easy tests for both of these, running with a parachute vs not, and running on a path next to a beach vs not.)

They may not be willing to make the claim just yet, but if my understanding of how they are calculating power is correct, then the value provided does account for varying wind conditions and running surfaces (although the metabolic cost of producing that power could vary).

As for a parachute, it would be simpler to just run a cord over a pulley behind a treadmill, and hang a known mass from it. In fact, this is an experiment I've been meaning to perform, although having pulled a calf muscle this a.m. it may take me a while to get around to it.
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Re: DCRainmaker preview of Stryd running power meter [Ale Martinez] [ In reply to ]
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Ale Martinez wrote:
Andrew Coggan wrote:
Speaking of precision:



(From http://club.stryd.com/...wer-in-children/1330)

Do you have data for different treadmill inclinations?

No, at least not yet, as the Stryd relies on a barometric pressure sensor to detect changes in elevation. That means it doesn't account for the additional power requirement of running uphill on a treadmill unless you collect data using the iOS or Android app, which allows you to specify the grade. To date, though, I've only been using a Garmin watch, so haven't elevated the treadmill.
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Re: DCRainmaker preview of Stryd running power meter [J_R] [ In reply to ]
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J_R wrote:
Andrew Coggan wrote:
trail wrote:
Andrew Coggan wrote:


2) it's going to take more than just common sense to take maximum advantage of the data that the Stryd can provide. Fortunately, some of us have more than just common sense at their disposal:


You're still in a logical trap with your quote. It clearly asserts that common sense is a sufficient condition to accomplish everything that's possible, with or without a powermeter.


Accomplishing the things I see possible is also going to take knowing more than just power.

Spring constants, anyone?


If this device cannot account for wind or other horizontal drag factors, is it really a power meter?

Granted, under most conditions it would not matter, but having run directly up and downwind at the Surfside Beach half marathon ( you are likely familiar with area & potential conditions) I know it is possible to have pace varied as much as 1 min/mile by wind with similar effort.

As I replied to Ray, I think it does account for a wind...and yes, I agree, Galvetraz Island can be quite windy!
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Re: DCRainmaker preview of Stryd running power meter [aw3] [ In reply to ]
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aw3 wrote:
Hahaha, I'm disappointed you deleted your reply! I thought it was entirely appropriate...

Me too, but I thought I should at least attempt to maintain some level of decorum.
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:

They may not be willing to make the claim just yet, but if my understanding of how they are calculating power is correct, then the value provided does account for varying wind conditions and running surfaces (although the metabolic cost of producing that power could vary).

As for a parachute, it would be simpler to just run a cord over a pulley behind a treadmill, and hang a known mass from it. In fact, this is an experiment I've been meaning to perform, although having pulled a calf muscle this a.m. it may take me a while to get around to it.


Andrew Coggan wrote:

No, at least not yet, as the Stryd relies on a barometric pressure sensor to detect changes in elevation. That means it doesn't account for the additional power requirement of running uphill on a treadmill unless you collect data using the iOS or Android app, which allows you to specify the grade. To date, though, I've only been using a Garmin watch, so haven't elevated the treadmill.

I'm afraid I don't understand how these two statements can be reconcilied: I don't see how they could account for varying wind conditions without measuring wind, but couldn't account for varying slope without altimeter data

Ale Martinez
www.amtriathlon.com
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Re: DCRainmaker preview of Stryd running power meter [Ale Martinez] [ In reply to ]
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Ale Martinez wrote:
I'm afraid I don't understand how these two statements can be reconcilied: I don't see how they could account for varying wind conditions without measuring wind, but couldn't account for varying slope without altimeter data

I think you'll get it if you think about it a bit.
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Re: DCRainmaker preview of Stryd running power meter [Tom Fort] [ In reply to ]
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I am interested in this product, however I will wait to see what others have to say before purchasing.
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Re: DCRainmaker preview of Stryd running power meter [mamilner26] [ In reply to ]
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mamilner26 wrote:
I am interested in this product, however I will wait to see what others have to say before purchasing.


I've got some via the coaches package. Some feedback:
  • The devices I gave out to some people I coach don't get used properly. They are not techy and didn't get excited about the data like I hoped they would so the other points relate to my experiences. I think when power is supported by watches while in run mode, it will be more easily digestible.
  • I've been recording data since August and find it interesting looking at the power data. Most of the time I train via heart rate or pace and don't feel like I NEED power. Given you can't cover as much ground on foot as by bike it normally means I'm running on the same terrain most of the time so I can compare overall training progress using pace @ heart rate.
  • My run test (4x1 mile all out effort) is on a flat path with little risk of injury with another person so I can do it outside. I wouldn't feel comfortable about doing a bike test outside as I would be more susceptible to riding into the back of a car or something.
  • I actually found then when I was running on sand the Stryd did seem to incorporate the terrain (i.e. watts on sand were worth less than watts on asphalt). I didn't do any specific testing to prove, it was just my perception so may be wrong.
  • I have a run test I did the other week and wish I had the power data to look into it (it was recording but the power was incorrect due to a firmware bug). I ran 4 miles (with a recovery) at exactly the same average heart rate but the times were very different (one I ran 5:28 and another at 5:57). This seemed like a huge difference and felt like power would have given me a chance to try and digest it. The bug is fixed now, so hoping to understand a bit more about pacing from the power data in future.

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