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Because the numbers are motion driven, rather than torque driven, I'm not sure that going dual sided would give you any better data...
I think this is actually a counterpoint. In cycling the kinematics are fixed so we know that no matter what happens, pedals are exactly 180 degrees away from left to right.
In running, one could have stride length differences, and other kinematic asymmetries at hips, knee, and ankle joints. If the leg with a Stryd sensor is left “dead” and one hops with the other leg, what would it report? There’s assumed symmetry and the errors are likely to be
more severe than single-sided cycling power meter measurements since there are more degrees of freedom to go wrong.
Garmin’s running power is based on torso measurements, which may be considered a single degree of freedom if it only has a single ~vertical accelerometer, and it would have to make assumptions about what the legs are doing based on this measurement.
A single-footpod accelerometer gives some data to reduce the assumptions but the other leg must still be modeled, and I assume Stryd must still require some form of accelerometer on the torso by communicating with wrist accelerometer and more assumptions, or completely models torso movement as well.
I hadn’t looked into Runscribe until today, but it’s impressive, and represents the
minimal amount of sensing required to avoid assumptions between hips and feet if using their two footpods + hip sensor.
That said, I find even Garmin’s data useful and have improved my running form based on its output, and I’m sure Stryd’s is similar or better. I think I would skip Stryd and stay with essentially free Garmin running power unless I’m willing to pay for runscribe’s 3-pc kit at $600, which is not bad compared to cycling power meters.