Fatigue level to address 'unequal TSS'?

Over the years i’ve noticed that my general exhaustion and required recovery time correlates closer with accumulated fatigue than purely TSS. That seems true even though TSS does contain an element of intensity in its calculation which gets reflected in ATL and TSB.

I’m wondering how useful the addition of “time in fatigue zone” would be? Something like
Hrs in “High Fatigue” (W’ bal < 33%)
Hrs in “Medium Fatigue” (34%< W’ bal < 66%)
Hrs in “Low Fatigue” (W’ bal > 67%)
for every ride. I suppose it might better reflect the effect of HIIT efforts on than just TSS?

These metrics would not affect the PMC chart, but they would be helpful in the planning process because they’d make recovery time required after a planned workout more accessible if visible in the training plan.

I know Work above FTP is already available and is a very useful metric.

So, this might be a bit of overkill …?

Interesting idea using W’bal depletion zones to measure impact of ride. I wonder if anyone has tried to do that?

I can’t take credit for the idea - Golden Cheetah has implemented this feature …

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This is very similar to the way Xert calculates XSS. As you pull down MPA (deplete W’ bal) the rate that XSS is accumulated increases, even for the same power.

In Xert, XSS is accumulated on a second by second basis. That’s not how TSS works (although you could calculate the TSS at every second and then take the difference to work out TSS/s at each point in the ride).

How does Golden Cheetah calculate this?


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Not sure what their algorithm is, but - naively - I think this could work:

  • we have the estimate or configured W’ for the althlete
  • we have W’(t) data stream for the ride
  • assuming one data point per second the tiz for high fatigue is just the count of data points where W’(t) < W’

I’ve seen the expected W’(t) even in the workout builder, so the tiz fatigue zones could be shown for Intervall workouts.

I think this would be useful. I have been doing a lot of inside training and while my CTL/fitness has plateaued at around 50, I feel like the usefulness of the fitness page is reduced for HIIT training as it will plateau given your FTP increases with your intensity, knowing work about FTP is fine, but a 1x5 min 120% effort has very different effect than 10x30s 200% efforts.

My understanding is probably lacking, but I thought I’d add to the conversation as I am starting to struggle with my planning as what is on the fitness page has begun to conflict with how I feel (freshness)

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