Training Load

by mechgt

Downloads: 12,931 (43) • Reviews: 16

Version:

2.0.6

Updated:

Feb 7, 2014

TRIMP Calculation

TRIMP Calculation

Postby jamesmora » Tue Feb 09, 2010 3:18 pm

What is the math behind the TRIMP calculations and weighting factors for zones, single zone, and dynamic?

It appears that zone based calculations is weighting factor * duration summed over each zone. Can you also explain how these weighting were derived? I'm trying to reconcile this with Bannister/MacDougall formula:

TRIMP = Duration * %HRR * 0.64*exp(1.92*%HRR) - for males
where %HRR = (Avg HR - RHR)/(MHR - RHR)

The values are close between the two, but not the same. Thanks,

JDM
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Postby mechgt » Tue Feb 09, 2010 11:19 pm

The Bannister model is what the TRIMP calcs are based on. The default factors are based on another formula that's different for males and females. Since there's no indicator in ST for this, I assume all ST users are males (sorry - it's not that big of a difference anyhow).

Your calculation looks like what I'm using (and would use .86 & 1.67 for females if that setting were available in ST athlete view).
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Postby jamesmora » Wed Feb 10, 2010 1:21 am

For a specific training session, the below is a comparison of calculated using %HRR and Training Load default factor values

Bannister - Factor (%HRR * 0.64*exp(1.92*%HRR))
0.5
0.8
1.5
2.2
3.7
TRIMP=168.5

Training Load - Default Factor
0.5
0.9
1.6
2.5
3.8
TRIMP=186.0

The difference in the TRIMP is due to the different weighting factors. Though the weighting differences are small it yields about a 17 TRIMP difference.

Do you use the same formula as the above to calculate the default values? I'm trying to understand the difference.

Thanks for your help! This is a great training tool. I am using this with the TSB guidance provided in the new book "The Runners Edge" (p 107 - 109) to help optimize my training plans. I'm assuming the same TSB guidance for TSS applies to TRIMP.

JDM
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Postby mechgt » Wed Feb 10, 2010 8:26 am

Assuming you understand all the settings (dynamic factors, single zone, etc):
When calculating the default factors, I use the average HR in the zone (as opposed to the upper or lower boundary HR). The formula I found (same as what you refer to) used the upper HR to calculate the zone, and I don't like that. To compensate for this difference, I multiplied by 1.0827. At this time, I don't recall where this number came from. It's possible that it was derived to make the avg. HR calculation match the already accepted factors using the upper-boundary calculation, but I'm not certain of this.
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Postby jamesmora » Wed Feb 10, 2010 9:11 am

Yes that's the difference. So your formula is

TRIMP = Duration * Weighting Factor

Where weighting factor =0.64*exp(1.92*%MHRR)*%MHRR*1.0827
and %MHRR = (Mean HR - RHR)/(MHR - RHR)

It would help if you could explain single zone and dynamic factors and how this relates to your posts about using 1) TRIMP=xxxx, 2) using manually entered Avg HR, and using 3) Actual HR data for the three types of methods to collect data to calculate TRIMP. I have done each of the three and they all seem to work great.

I understand the zone based method which you would need HR data (#3) to know time in zone and Avg HR for each zone and just the Avg HR would naturally lend to a single zone method (#2). But I'm just guessing.

Thanks for your time and explanations.
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Postby mechgt » Wed Feb 10, 2010 11:02 pm

jamesmora wrote:It would help if you could explain single zone and dynamic factors and how this relates to your posts about using 1) TRIMP=xxxx, 2) using manually entered Avg HR, and using 3) Actual HR data for the three types of methods to collect data to calculate TRIMP. I have done each of the three and they all seem to work great.

I understand the zone based method which you would need HR data (#3) to know time in zone and Avg HR for each zone and just the Avg HR would naturally lend to a single zone method (#2). But I'm just guessing.

Thanks for your time and explanations.


Single Zone - The intent here is to allow you to setup a HR zone category with lots of small zones. This will allow finer resolution of the calculation. If unchecked, it will use the associated HR zone setup (running, cycling, etc.) These are typically broader zones and not as good for the calculations. Recommended setting: enabled with a specific TRIMP HR category with lots of small zones.

Dynamic factors - If you accept my default factors (that are based on HRrest and HRmax), then I suggest that you enable this. This will allow you to change your HRrest and HRmax, and your historical calculations will not change. In contrast, if you don't check it, and you update your factors (because HRrest or HRmax change), then these changes will be applied to historical activities as well. Recommended setting: Enabled and track your HRrest and HRmax over time.

In order of precedence:
Manual Entry - None of this applies to manual entry (TRIMP=xxxx).
HR Data track - it's applied as described above.
AvgHR - If you enter a HR here, it's calculated as if your entire activity were at this HR. It's crude, but it's better than nothing if you don't have data or a guess for manual entry. Factor is selected as described above.
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Postby Stumpjumper68 » Thu Feb 11, 2010 7:04 am

AvgHR - If you enter a HR here, it's calculated as if your entire activity were at this HR. It's crude, but it's better than nothing if you don't have data or a guess for manual entry. Factor is selected as described above.


You can create your own HR data track with ST core function >Change activity/data tracks. It works like a recorded track than.
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Postby jamesmora » Thu Apr 01, 2010 10:17 am

After upgrading today, I noticed my TRIMP/CTL/ATL jumped up a few points. Has the math changed? Thanks.
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Re: TRIMP Calculation

Postby joem » Thu Aug 18, 2011 2:51 am

Trimp method is itself a simple maths, which makes a great deal of sense in terms of calculating a "dose" of aerobic training.
TRIMP = training time (minutes) x average heart rate (bpm). For example, 30 minutes at 145 bpm. TRIMP = 30 x 145 = 4350.
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Re: TRIMP Calculation

Postby mechgt » Thu Aug 18, 2011 6:27 am

joem wrote:Trimp method is itself a simple maths, which makes a great deal of sense in terms of calculating a "dose" of aerobic training.
TRIMP = training time (minutes) x average heart rate (bpm). For example, 30 minutes at 145 bpm. TRIMP = 30 x 145 = 4350.


A simplified version of it is...
TRIMP = time in zone * (HR Zone Factor)

HR Zone factor is a small number based on avg HR Very similar to what joem said, however the resulting generally accepted TRIMP range is in the 0 - x00 range, rather than the thousands (avg workout might TRIMP 150 for example). The main difference being the scaling and offset difference between AVG HR and a small factor number. Concept is the same, however you cannot apply literal numbers directly to it as shown in the above example.

Anyway, to answer the original question, did any calculation change... no.
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