I’ve communicated to @david that displaying Bannister’s TRIMP will be a good addition to s-SPE based load metrics previously implemented.
Bannister’s TRIMP = A.B.C
A = Duration (minutes)
B = Delta HR ratio
= (HRexercise - HRrest)/(HRmax - HRrest)
C = (0.64.e^1.92.B) for males
or (0.86.e^1.67.B) for females
e = 2.712
C is a pre-evaluated co-efficient of blood lactate rise for males and females with increase in intensity.
Bannister’s TRIMP maybe useful as a load metric and adds potential value over the current non-power load metric available, which may not generalize well to other sports outside of cycling.
I just played around with the Load and Bannister’s TRIMP numbers of a HR-based cycling session.
I would expect that both numbers to approx. match, but the Load number was way lower (250 Vs 380). It was set the normalized TRIMP as the HR load model (default). If I set time in zones or average HR the load value increases, average HR almost matches the TRIMP value (384).
So how should I assess all numbers. What is your impression about the most realistic load estimation?
I wouldn’t get too hung up on comparing the precision of Load and Bannister’s TRIMP. Understand the differences in the math.
Bannister’s TRIMP is a pretty well studied metric . Dependencies are exponents where co-efficients for males and females come out of a paper I referenced earlier, plus its also dependent on the resting heart rate in your settings.
Is it sensitive to individual cases?
Probably somewhat, probably not at all. If you need more sensitive metric, you may need an individualized TRIMP solution based on your own blood lactate rise with intensity. Something like that can be programmed using Golden Cheetah. For most people, this is already taking things too far.
Btw, I don’t really know where the HR Load estimation methodology comes from. I expect David to enlighten us.
In my personal case, I use TRIMP & s-RPE scores which form two subjective measures of training load. Then I combine it with some objective measure. For running, if I have pace, that’s fine. If its cycling, then power works.
The HRSS load model is from Elevate. This is TRIMP normalized to more closely match power based training load. Normal TRIMP numbers are a lot higher than TSS from power which is what Intervals.icu uses for power based load. As far as I know HRSS is TRIMP but on the same scale as TSS.
Thanks for the link, David! This make things clear.
To me, it looks like the Load value is the normalised TRIMP:
hrPSS = Exercise TRIMP/ 1hr FTP TRIMP *100
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Note that an hrPSS is always going to be less accurate than a calculation based on a power meter, something that is also made clear in TrainingPeaks. But I do believe that an hrTSS is better than a TRIMP, as it is comparable between different athletes, conceptually easier to understand and takes account of changes in fitness levels that alter the FTP heart rate.
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I was though confused about his comment in the tooltip of the HRSS:
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Either the time in each HR zone or the average HR for each activity is used. This works well for cycling but does not generalize well to other sports. For running and other sports HRSS (from Elevate) works better.
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I find it confusing why HRSS is chosen as default for cycling.
Mostly because it gives good results with very little data (avg HR for the ride, resting HR, LTHR, max HR). Time in zones needs a lot of rides with power and HR to give good results.