Hi all,
I was wondering if anyone had come across any research into the accuracy of the power data produced by Stryd foot pods? Coming from a cycling point of view I have become accustomed to the reliability of certain power meters.
I have just started using a stryd and I’ve noticed the power data is slightly higher than my cycling power. I’ve read that this is normal. I guess my question is whether anyone knows the +/- tolerance to the power data from stryd?
I have come to this question because (prior to Garmin’s recent change) the kcal and kj expenditure for a given workout was fairly similar when I did a cycling workout. However the kcal v kj expenditure during a run is considerably further apart since I’ve started using stryd for running…as much as 30% higher for kj. As kj is mathematically linked to the power output I was wondering if anyone knew of +/- tolerance data.
Thanks
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I’ve been running with a Stryd since January. My main observation is that you can’t compare running power to cycling power. Cycling power usually comes from some sort of direct force measurement whereas running power is a pseudo measure calculated from accelerometers in the pod. I think even Stryd have accepted this now. Running power tends to be higher than cycling power (well for me anyway). For example my cycling CP is ~320W compared to 380W for running, and I easy ride at ~200W but am about 280W for an easy run. I’m still researching how the power-duration curves compare for both., but this sort of makes sense in that a long easy run may be 2 hours whereas a long easy ride could be 4+ hours (for the pros anyway!).
As for accuracy, I think you need to look at running power as a personal measure, i.e. how does my power compare today against yesterday etc. I’m not sure how well you can compare running power across athletes. Also, I’m having an issue with my Stryd in that over ~5K with the pod on my left foot it will measure about 150m further than when on my right foot. I still trying to understand why with Stryd support and don’t know if this affects the reported power. But as long as you’re consistent on how you measure (pod at same position on same foot) then I think you can compare across your runs ok.
I do like using the Stryd though as its more reactive than heart rate and you can also get into HR/Power decoupling on longer runs.
Hope that helps
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I use the Garmin HRM-Tri and it also gives me power when running.
As you noted, I find it useful for tracking runs against runs, and for things like running form.
The key is repeatable measurements, which is what these pods and straps give you. It takes out the inconsistencies of HR for measuring your training load.
My running FTP is quite a bit higher than my cycling one, and I had found a previous article about why. This one covers a lot of it as well. - How Is Running Power Different from Cycling Power? (Part 3) – VeloPress
As for @John_Peters_endura.f point. With the stryd, make sure it’s always in the same place. Your legs are actually different lengths even if only by a fraction of an inch. Your stride length is also different from left to right because of both the length and how your muscles move. (Think about how sometimes one hip or calf hurts more than the other) So keeping the pod in the same place over and over will give you the best data.
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