How is Training Stress calculated here?

[Dave_C_Purdy]

How is Training Stress calculated here?

This is a more general question…

But specifically, does the TS increase linearly over time, or is there some exponential component?

Does it depend on watts, or watts/kilogram?

Does it depend on HR?

Suppose Cyclist A rides for 3 hrs at 3w/kg, continuously, on a trainer. A week later, he rides identically at the same intensity, but in 3 1-hour blocks, with a substantial rest between those blocks.

Would he get the same Training Stress in those two different situations? (To me, the first would seem quite a bit tougher…)

[Gerald]

It depends if you use Power, HR (HRSS, Ave HR or TIZ) or Pace, and the order of priority set in /settings page.

Power is calculated the same way as TrainingPeaks, with non-moving time ignored. So that is:
TSS = (sec x NP x IF) / (FTP x 3600) x 100

Some previously discussed topics with response from David:

Load // Strava/Intervals

Tx. The Intervals.icu load for that run has been calculated from the HR data using HRSS and the number looks “good” (103 for a 1h17 run is 88% intensity which is reasonable). This is designed to produce numbers similar to what you might get from power data for the same activity (TSS formula). In general a 1hr max effort should get you load of about 100. I don’t know how Strava and Garmin calculate their numbers (165 and 162). They is clearly not on the same scale as TSS. Intervals.icu tries to…

How training load estimation from HR works

Intervals.icu has 2 ways to estimate training load from activities with only heart rate data and no power. You can change between them in /settings: [Screen Shot 2020-01-22 at 05.36.34] The default “Time in HR zones” model uses the moving time in each heart rate zone. Your previous activities with power and heart rate are used to build a linear regression model to estimate training load. If there are not enough activities then a general (not athlete specific) model is used. Essentially each H…

How is calculated Training Load?

I noticed that the training load value is an average between (heart rate tss and Tss of training peaks); how is it calculated? is the relative effort of Strava?

[Gerald]

@Dave_C_Purdy

Suppose Cyclist A rides for 3 hrs at 3w/kg, continuously, on a trainer. A week later, he rides identically at the same intensity, but in 3 1-hour blocks, with a substantial rest between those blocks.

Would he get the same Training Stress in those two different situations? (To me, the first would seem quite a bit tougher…)

You are correct to assume that the first workout will be a bit tougher, as TSS/Load doesn’t account for the changes in the calculation, so load after 1 hour will be the same at 3 hours, assuming the intensity and normalised power is the same.

[Dave_C_Purdy]

Thank you Gerald!