Correlating workload between Polar and PT

I suppose you could export a bunch of your PT workout files and study the relationship between power and HR (e.g., linear regression). You could then build an algorithm to convert HR to power and create a .csv file for import into CP. I wrote a utility for that purpose at another thread around here somewhere.

peterwright said:

If I am riding MTB with my Polar and road with my PT and using CP for data analysis, how can I best estimate training load from MTB rides so that I can keep track of weekly training load ? Can I use energy consumption and if so do the two units measure this in the same way ? It would appear that Polar energy readings and PT energy readings differ significantly for the same ride.

Thanks

CP can calculate energy consumption from either HR or Power. Would be interesting to see if the CP calculation from HR correlates with the polar one. However, if CP is performing the calculation from both files you should get the same number - it probably defaults to power if the data is available.

Certainly calculating energy consumption from power should be a lot more accurate. Energy from HR must be based on some statistical approximation. I suspect this is why Polar software asks you for your activity level.

Bruce Diesel said:

CP can calculate energy consumption from either HR or Power. Would be interesting to see if the CP calculation from HR correlates with the polar one. However, if CP is performing the calculation from both files you should get the same number - it probably defaults to power if the data is available.

CyclingPeaks doesn't calculate energy consumption, only external work production (in J) from power (in W) and time (in s).

acoggan said:

CyclingPeaks doesn't calculate energy consumption, only external work production (in J) from power (in W) and time (in s).

I stand corrected, I am neglecting efficiency which in the human body is quite poor.

However, my point is about calculating work based on heartrate, as opposed to power and time. Calculating work based on HR must be based on some statistical model, and using power/time would be far more accurate for a given individual.

Looking at CP now, I cannot find anything that allows work to be calculated from HR - I am confusing CP with the software I got with the PT.

peterwright said:

It would appear that Polar energy readings and PT energy readings differ significantly for the same ride.

In general, my Polar 710i estimates calories about 66% higher than the PowerTap.

For example for similar intensity and duration rides in the last couple of weeks:
Polar: 900 kcal/hr
PT SL: 540 kcal/hr

I don't know if that 66% relationship would hold for anyone else though. Probably not.

peterwright said:

If I am riding MTB with my Polar and road with my PT and using CP for data analysis, how can I best estimate training load from MTB rides so that I can keep track of weekly training load ? Can I use energy consumption and if so do the two units measure this in the same way ? It would appear that Polar energy readings and PT energy readings differ significantly for the same ride.

Thanks

Last week omeone on the wattage list suggested this to compute TSS with heartrate:

IF = (Avg HR for Workout - Resting HR)/(Threshold HR - Resting HR)
TSS = IF * IF * durations (in hours) * 100