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Re: DCRainmaker preview of Stryd running power meter [sciguy] [ In reply to ]
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sciguy wrote:
Trev wrote:
But I understand running pace is a function of power. Does this mean a 10% increase in pace requires 10% more power?
If this is the case I can see Dr Coggan's point of view.

This is pretty much the case especially at the speeds triathletes typically run which I believe has been Andy's main point all along.

Hugh

Yep. So you might as well use pace.
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Re: DCRainmaker preview of Stryd running power meter [Trev] [ In reply to ]
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Trev wrote:

But I understand running pace is a function of power. Does this mean a 10% increase in pace requires 10% more power?

I hope I don't come across as pedantic, as subtleties such as this can result in mis-communication or misunderstanding:

"A function of" does not necessarily mean a 1:1 ratio. For example, pace could go up with the square root of power, Power = speed^2, and it would still be a function of pace. In the same sense, assuming flat ground and no wind,for cycling speed is indeed a function of power, it's just a more complicated one.
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Re: DCRainmaker preview of Stryd running power meter [YTS] [ In reply to ]
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YTS wrote:
Trev wrote:

But I understand running pace is a function of power. Does this mean a 10% increase in pace requires 10% more power?

I hope I don't come across as pedantic, as subtleties such as this can result in mis-communication or misunderstanding:

"A function of" does not necessarily mean a 1:1 ratio. For example, pace could go up with the square root of power, Power = speed^2, and it would still be a function of pace. In the same sense, assuming flat ground and no wind,for cycling speed is indeed a function of power, it's just a more complicated one.

No not pedantic at all. This is exactly why I was asking the question, because I wasn't sure of the exact meaning.
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Re: DCRainmaker preview of Stryd running power meter [davearm] [ In reply to ]
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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.
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Okay, then how do I go about determining how hard/fast I should I run up that hill I come upon in my Ironman race? I don't know its length or its grade. Heck I've never been on the course before. I just know I'm going uphill.
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Re: DCRainmaker preview of Stryd running power meter [davearm] [ In reply to ]
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davearm wrote:
Okay, then how do I go about determining how hard/fast I should I run up that hill I come upon in my Ironman race? I don't know its length or its grade. Heck I've never been on the course before. I just know I'm going uphill.

Perceived exertion. At least in experienced athletes competing under conditions they've been exposed to before, it works just as well any theoretically-optimal pacing strategy (see, e.g., Alex Simmon's "pacing optimization index").
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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:
Perceived exertion. At least in experienced athletes competing under conditions they've been exposed to before, it works just as well any theoretically-optimal pacing strategy (see, e.g., Alex Simmon's "pacing optimization index").


That's a lot of assumptions.

Perceived exertion is probably the worst measure for the less experienced athletes especially in endurance events where the conditions, course or both is not familiar. I can think of numerous times when I'm running uphill at what I think is steady effort, yet my HR spikes to sub threshold levels. I'd argue that Biking Power meters helps LESS experienced athletes more then more experienced athletes and IF this device works consistently and as billed will be a game changer.
Last edited by: Olu: Feb 17, 15 8:42
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Re: DCRainmaker preview of Stryd running power meter [Olu] [ In reply to ]
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Olu wrote:
Andrew Coggan wrote:
Perceived exertion. At least in experienced athletes competing under conditions they've been exposed to before, it works just as well any theoretically-optimal pacing strategy (see, e.g., Alex Simmon's "pacing optimization index").


That's a lot of assumptions.

Not really - like I said, see Alex's paper.

Olu wrote:
Perceived exertion is probably the worst measure for the less experienced athletes especially in endurance events where the conditions, course or both is not familiar.

First, note my caveats above.

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...
Last edited by: Andrew Coggan: Feb 17, 15 9:34
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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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.

I bet you can imagine that it's very difficult for triathletes (or anyone really) to believe that cycling and running are so fundamentally different that a tool that can accurately and predictably measure power* is vital in cycling, but worthless in running. The parallels between the two seem way too clear for this to be true.

* assuming this Stryd or something else like it could achieve this
Last edited by: davearm: Feb 17, 15 10:14
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:
"Game-changing" indeed...

You seem pretty certain...I guess you're the expert.

Only time will tell if you're right.
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Re: DCRainmaker preview of Stryd running power meter [davearm] [ In reply to ]
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* assuming this Stryd or something else like it could achieve this[/quote]
I think this is his point (not to speak for anyone), If you had a perfect scenario where the device works in the same fashion as a PM and has the same clarity with running IE power correlates reasonably to metabolic demands then maybe a great pacing tool.

I don't think this is the case yet….perhaps I will be proven wrong or maybe better/different products will evolve.

The Issue is that with the bike holding a power level that is even and achievable throughout the ride (in order to run well) should correlate to an RPE of "pretty easy to moderate" from minute 1 to 5-7hours, with the run even pacing or a slight positive/or negative split usually correlates to a variable RPE through out.

So a simple stopwatch for me is the best tool for IM run, it is the one event (IM Run) where there is perhaps a really strong negative correlation to RPE and pace….(talking as a coach) If this was actually proven to work then I could see it as a really good "slow the F*&k down" meter in the first 10km.

But for now we do something really simple, in the first 5-10km of the run you hold 15-30seconds SLOWER than goal pace, 10-32km hold goal pace, 32-42km…..it's a F%$king race….dig deep.

Maurice
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Re: DCRainmaker preview of Stryd running power meter [sciguy] [ In reply to ]
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sciguy wrote:
Trev wrote:
But I understand running pace is a function of power. Does this mean a 10% increase in pace requires 10% more power?
If this is the case I can see Dr Coggan's point of view.


This is pretty much the case especially at the speeds triathletes typically run which I believe has been Andy's main point all along.

Hugh

I suspect it's far from linear. In particular when you become more fatigued. Also at certain paces or uphill vs. downhill.

It is true over a range of paces on relatively flat ground.

But I don't have hard data, it's what I've come to believe looking at me own data and some of my clients. Below a certain pace, their run mechanics change and the ratio of pace to energy output changes.

I also know one athlete that has a very narrow range between aerobic threshold and lactate threshold. Very narrow. I suspect it's a main reason he performs much better in 70.3 compared to IM. You can cross that line frequently without penalty. You cannot in IM.


TrainingBible Coaching
http://www.trainingbible.com
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Re: DCRainmaker preview of Stryd running power meter [motoguy128] [ In reply to ]
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I think the primary point and benefit/value, and Coggan points towards this, running has variable mechanics. They vary uphill, downhill, at different paces and with fatigue. For elite runners with very well refined mechanics, I think there would be less value for this device. But for triathletes, or more recreational runners, with more variability in mechanics, might see greater benefit.

Right now if I improve my run mechanics I have to use RPE and HR to gauge improvement compared to pace. I don't know how hard I'm accelerating in a horizontal direction. I don't know if HR shifts are due to fatigue, hydration, heat, fitness gains, too much food in my stomach, excitement, a range is variables. Pace is impacted by weight, grade, wind, road surface.


TrainingBible Coaching
http://www.trainingbible.com
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Re: DCRainmaker preview of Stryd running power meter [mauricemaher] [ In reply to ]
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Targeting particular run paces over given distances is all well and good, but I'm still left wondering about how much I should slow down when I'm on the course, and come to a hill. The answer is surely somewhere between "not at all" and "walk it", but I've got no good guess as to where that optimal pace/effort adjustment lies.

This is information I figured a run powermeter (properly executed) would tell me, just as my bike powermeter does already.

Maybe the answer is, slow down however much it takes to keep the RPE the same. That just seems highly unscientific, where some science might be available.
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Re: DCRainmaker preview of Stryd running power meter [davearm] [ In reply to ]
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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.
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Re: DCRainmaker preview of Stryd running power meter [Olu] [ In reply to ]
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Olu wrote:
Andrew Coggan wrote:
"Game-changing" indeed...

You seem pretty certain...I guess you're the expert.

Only time will tell if you're right.

I'm simply explaining the logic behind my prediction.
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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:
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.

Feel is the most valuable tool. Sadly since the advent of heart rate monitors and power meters it is often neglected.

When you talk of perceived exertion, are you referring to it in a narrow scientific Borg scale sense or in a more broad sense as another way of referring to feel in general?
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Re: DCRainmaker preview of Stryd running power meter [motoguy128] [ In reply to ]
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motoguy128 wrote:
sciguy wrote:
Trev wrote:
But I understand running pace is a function of power. Does this mean a 10% increase in pace requires 10% more power?
If this is the case I can see Dr Coggan's point of view.


This is pretty much the case especially at the speeds triathletes typically run which I believe has been Andy's main point all along.

Hugh

I suspect it's far from linear. In particular when you become more fatigued. Also at certain paces or uphill vs. downhill.

It is true over a range of paces on relatively flat ground.

But I don't have hard data, it's what I've come to believe looking at me own data and some of my clients. Below a certain pace, their run mechanics change and the ratio of pace to energy output changes.

I also know one athlete that has a very narrow range between aerobic threshold and lactate threshold. Very narrow. I suspect it's a main reason he performs much better in 70.3 compared to IM. You can cross that line frequently without penalty. You cannot in IM.

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.
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Re: DCRainmaker preview of Stryd running power meter [motoguy128] [ In reply to ]
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motoguy128 wrote:
I think the primary point and benefit/value, and Coggan points towards this, running has variable mechanics. They vary uphill, downhill, at different paces and with fatigue. For elite runners with very well refined mechanics, I think there would be less value for this device. But for triathletes, or more recreational runners, with more variability in mechanics, might see greater benefit.

Right now if I improve my run mechanics I have to use RPE and HR to gauge improvement compared to pace. I don't know how hard I'm accelerating in a horizontal direction. I don't know if HR shifts are due to fatigue, hydration, heat, fitness gains, too much food in my stomach, excitement, a range is variables. Pace is impacted by weight, grade, wind, road surface.

Sounds like what you'd really like to able to measure are things like stride length, contact time, flight time, etc., not power.
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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:
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.
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Re: DCRainmaker preview of Stryd running power meter [Andrew Coggan] [ In reply to ]
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Andrew Coggan wrote:
motoguy128 wrote:
I think the primary point and benefit/value, and Coggan points towards this, running has variable mechanics. They vary uphill, downhill, at different paces and with fatigue. For elite runners with very well refined mechanics, I think there would be less value for this device. But for triathletes, or more recreational runners, with more variability in mechanics, might see greater benefit.

Right now if I improve my run mechanics I have to use RPE and HR to gauge improvement compared to pace. I don't know how hard I'm accelerating in a horizontal direction. I don't know if HR shifts are due to fatigue, hydration, heat, fitness gains, too much food in my stomach, excitement, a range is variables. Pace is impacted by weight, grade, wind, road surface.


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

I sure would. That and ground reaction forces. I would rather know those things than power (for running).

Simplify, Train, Live
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Re: DCRainmaker preview of Stryd running power meter [davearm] [ In reply to ]
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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:
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.


http://www.uta.edu/...rior%20statement.pdf

It would be unscientific to ignore RPE.
Last edited by: Trev: Feb 18, 15 10:11
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Re: DCRainmaker preview of Stryd running power meter [Mike Prevost] [ In reply to ]
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in terms of ground reaction forces. DC Rainmaker's article did show that Stryd's data closely matches the impact forces recorded on a lab grade force-plate treadmill. If validated, I definitely see the benefit in possibly doing a greater number of field studies outside of the lab - maybe putting the pod on the shorts of elite marathoners who live and train in the Rift Valley region and using the device on elite runners during races - capturing data over the course of an entire marathon, for example. The potential to research mechanical efficiency is real. And future [lab] studies comparing Stryd's running power to glycogen utilization over varying speeds and gradients will be interesting.

___________________________________
milesthedog on strava
Last edited by: milesthedog: Feb 19, 15 8:43
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Re: DCRainmaker preview of Stryd running power meter [Tom Fort] [ In reply to ]
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Kickstarter just opened up for the Stryd less then 1 hour ago and has almost met it's goal...


https://www.kickstarter.com/projects/stryd/stryd-the-worlds-first-wearable-power-meter-for-ru/



Jeff Dell
Endurance Tracker - For the data driven athlete.
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