one additional comment and then I have to sign off - but I’ll read your response(s):
To the comments that Stryd is really only good for monitoring form, this is something I disagree with.
Who said that?
What I would respond with is that running is like cycling with the exception that it’s like riding a bike where the wheel can suddenly change into an octagon or square - obviously, that’s going to increase power while decreasing speed. So, if using that analogy or using a more realistic analogy of it being like a brake pad rubbing, Stryd measures power for an activity that is much more dynamic that cycling, and from my experience, it is doing it pretty well.
Now, I will say that Stryd (as is the same with HR and GAP), the power drops too much on downhills if a watt is representative of a Calorie. I think that’s largely due to the ‘torque’ factor being isolated to the movement and change in motion of the foot (or body with the original chest strap version). But, the energy required for knee and hip flexion are other sources of ‘torque’ not captured by Stryd that do increase Calorie expenditure and also increase mm lactate/l blood, so if FTP is equal to 4mm/l, Stryd is not providing that measurement. I equate it to holding a high cadence on a descent while biking; I can still maintain very high power but if the torque were being measured as a function of change in forces between the tire and the ground, power would be reduced on downhills more than it should be, but because torque is measured as force applied to the pedal, power is still accurate while cycling downhill. Stryd running power is not accurate while running downhill according to what I’d describe as my fine-tuned PE and perceived lactate level in my legs, chest and remaining body depending on the effort. Stryd needs to factor in change of movement at the knees and hips; I’m fairly certain, from data I’ve personally collected and analyzed in my own hobby-studies while conducting research at Ithaca College and Harvard, Stryd’s foot sensor can capture change in knee and hip angles from a footpod, though two footpods would be better, as minor imperfect bilateral movements can have huge consequences in running form.
So if I understand you correctly, you’re judging the accuracy of Stryd’s power measurements on downhills based on your perceived exertion?
I’d go so far as to say that with two footpods, a stick figure could be created (side view) allowing the user to see their form in live time, and a second stick figure could be created representing ideal form. Put these in a heads up display, overlapped, and allow the user to match the stick figures movements to reduce “form power”. That would be my ideal use of Stryd: Power and the ability to see when my ‘wheel’ isn’t round and to fix it with visual feedback.
Now, I do fully expect you to deconstruct that pseudoscience above to the nth degree, but I hope in the process you can take the feedback as something worth considering and addressing, as this is not just my perception of Stryd, but also the perception of my peers who are using the new Stryd. Thank you
Many people love the idea of using technology to help them achieve their “perfect” running form. The problem is that the former can’t easily be defined, at least for a given individual. For example, Bill Rogers had a famously asymmetrical arm swing…would he have been able to run even faster if he had corrected the “problem”? Peter Cavagnaugh was smart enough to know that the answer to that question was “hard to say, but I’m not the one who is going to mess with success.”
