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?
