FYI - You can get the basic decoupling ratio from the Calculated Fields plugin. Doesn't give you the trace, but still provides useful insight over time.
There's a standard function for the Speed:HR decoupling ratio for active splits - DECOUPLINGRATIOACTIVE. See screen shot below for setup. This works well for running, but might give a slightly different result to a Power:HR decoupling ratio for cycling.
If you're inclined, you could create a new Power version. Or request it be added as a standard function? Something like:
Power:HR Ratio = ({FirstHalfActivePowerHRRatio}-{SecondHalfActivePowerHRRatio})/{FirstHalfActivePowerHRRatio}*100
using Virtual expressions for
FirstHalfActivePowerHRRatio = {ACTIVERANGEPower(Distance,0,{HALFDISTANCE})}/{ACTIVERANGEHR(Distance,0,{HALFDISTANCE})}
and
SecondHalfActivePowerHRRatio = {ACTIVERANGEPower(Distance,{HALFDISTANCE},{DISTANCE})}/{ACTIVERANGEHR(Distance,{HALFDISTANCE},{DISTANCE})}
You can then include the custom field in your activity report layout. This can give interesting insights on relative fitness over time, if not actually within an activity.
