Stryd measures how hard you push off the ground right? So in theory it could tell me whether a tempo in next% on a dirt road was better than a track workout in spikes or a road tempo in standard flats was, right?
Stryd measures how hard you push off the ground right? So in theory it could tell me whether a tempo in next% on a dirt road was better than a track workout in spikes or a road tempo in standard flats was, right?
Charles Martel wrote:
Stryd measures how hard you push off the ground right? So in theory it could tell me whether a tempo in next% on a dirt road was better than a track workout in spikes or a road tempo in standard flats was, right?
Stryd doesn't measure direct force. It'll capture motion through 3D space.
It depends what your definition of "better" is in this case.
Better (less) Ground Contact? Better horizontal vs vertical ratio? Less power for the same pace? Lower form power ratio?
Totally depends on what you're looking for.
By "better" I mean more power. Doesn't more power mean faster? What would these other metrics tell me? That am more efficient at one pace than another? That certain shoes make me more or less efficient?
Charles Martel wrote:
By "better" I mean more power. Doesn't more power mean faster? What would these other metrics tell me? That am more efficient at one pace than another? That certain shoes make me more or less efficient?
I think you are falling into a black hole of knowledge and information. Once you question one concept (efficiency in this case), you realize that you don't really know what that means, and then you dig into a sub-concept (power), and realize that is a bit opaque as well. That could be a good thing - that's how I learned what I know.
There are just too many unknowns in your knowledge equation right now. I think you need to learn about the fundamental concepts before trying to apply them in a complicated way like this. Let me summarize what I believe is happening here:
You want use a device you don't understand (Stryd)
...in order to infer the value of a poorly-defined quantity (efficiency)
...by measuring a quantity you aren't sure what to do with (power)
...in order to quantify the effects of a piece of equipment that experts don't fully understand (shoes).
It sounds like you are looking to come to some quick conclusions about the effect of vaporflies, without understanding the chain of complicated mechanisms I mentioned above. Your resulting conclusions will be generally worthless, because you won't know what went into them or what to do with them. Your conclusions could end up being the complete opposite of the truth, but you wouldn't have the tools to know otherwise.
But it also sounds like you are on the cusp of really digging into the running orthodoxy: rather than accepting "vaporflies make you more efficient", you are exploring what that even means. Most people look for the quick-and-easy rules and could care less about the real science happening beneath the surface.
If this post is frustrating, I've done my job. There is no good answer to the question you're asking - only things to chew on.
They (Stryd Support) confirmed to me that they can't account for race surface - meaning that the exact same effort on the road will result in a higher power reading that on a soft and muddy cross country course. Not sure that helps you or not.
Good reply from Trail Zealot above on the overall concepts!
To answer your follow up, more power is not always better. Your ability to hold more power for a longer duration can lead to an improvement in performance, but there are other figures.
forcerunner wrote:
Good reply from Trail Zealot above on the overall concepts!
To answer your follow up, more power is not always better. Your ability to hold more power for a longer duration can lead to an improvement in performance, but there are other figures.
Thanks forcerunner I'm blushing :)
One other thing I forgot to mention about power: there are two kinds.
There's mechanical power: related to how hard your feet are pushing on the pavement (that's what stryd measures). And there's metabolic power: your body's internal calorie burn rate (that's what they measure in a lab when they analyze the air you breathe in and out). Your metabolic power (your engine) responds to mechanical power demands over time (like how it takes a while to warm up when you start running, or to cool off when you stop). Heart rate is an indirect way to get a sense for your metabolic work rate (it's not great).
The word "efficiency" can refer to a lot of things, just like "power". But in general, efficiency refers to the ratio of your mechanical power to metabolic power. If you are really "inefficient", you will be spending a lot of metabolic power in your body, but you won't be doing much mechanical work in the real world. Efficiency = (mech work) / (met work) is low in this case. Think of that new runner with horrible form, flailing all over the place and working hard to go nowhere. The same runner can go faster simply by becoming more efficient - without needing to make their engine bigger! That's how pros improve. They generally aren't increasing their VO2max (engine); they are improving their efficiency.
TLDR: If you can run substantially faster in one pair of shoes than another (under the same conditions), while maintaining the same sense of perceived exertion / breathing rate / heart rate, that probably means one of two things: the shoes have reduced the mechanical power needed to move your body at a given pace (maintaining the same efficiency of conversion from mechanical power to metabolic power), or the shoes have somehow increased the efficiency of that energy conversion itself. I don't think you'd be able to tell the difference on your Stryd readout, however.
No offense to him, but I think you can disregard Trail Zealot's pretentious ramblings. The answer you're looking for is a qualified "yes". If you run the same course/surface at the same speed under similar conditions (particularly wind, though the newest Stryd with wind adjustment should help), you'd be looking for the shoe that results in lower power. Why lower? Because it would indicate that you needed to generate less power to run the same speed, which is obviously the preferred outcome.
Yes, it's not a perfect comparison, but if the power is noticeably lower at the same pace, etc., then that is telling and will give you enough of an answer.
Thank you for more concisely re-stating my TLDR ;)
While I do tend to get verbose, it's only because I want to qualify my answer, and not over-simplify or answer a question that isn't being asked. I think a lot of times when we ask a question, the most truthful response is one that makes us ask more questions.
Trail Zealot wrote:
Thank you for more concisely re-stating my TLDR ;)
While I do tend to get verbose, it's only because I want to qualify my answer, and not over-simplify or answer a question that isn't being asked. I think a lot of times when we ask a question, the most truthful response is one that makes us ask more questions.
Take your Socratic discussion back to the middle School you teach at. No one on an anonymous online message board is interested in your psuedo intellectualism.
moran112312 wrote:
Trail Zealot wrote:
Thank you for more concisely re-stating my TLDR ;)
While I do tend to get verbose, it's only because I want to qualify my answer, and not over-simplify or answer a question that isn't being asked. I think a lot of times when we ask a question, the most truthful response is one that makes us ask more questions.
Take your Socratic discussion back to the middle School you teach at. No one on an anonymous online message board is interested in your psuedo intellectualism.
This IS the middle school I teach at.