Different IF and TSS for same ride - how to train 1h30

This is nitpicking, but I was surprised by the IF and hence TSS calculated by WKO for 3 rides of my standard circle. It is a 1h30 look with a 300 climb (through the vinyards) and flat return along the Lac Leman. Here are 3 consecutive rides:
1) 1h34, IF 1.04 TSS 170 awg 192W norm 229W
2) 1h25, IF 1.09 TSS 169 awg 212W norm 240W
3) 1h32, IF 0.99 TSS 149 awg 178W norm 219W

In ride 3), I rode hard, ran out of sugar, bonked and rode much slower last 20 minutes. Still, I was faster than in ride 1). And certainly, it felt like a harder workout than in ride 1).

This would suggest that for fixed exercise duration and distance, a ride at constant power is given higher TSS than riding hard for 2/3 and then relaxing the last 1/3. Granted, these are short training rides, but it is opposite to the old-school training regime I was taught a decade ago was to ride hard out and creep back. Any thoughts?

More practically: if boundary conditions for my training are such 1h30 rides, should I aim for constant power (which would optimise TSS), or should I ride intervals, ending with creeping home?

Read this . TSS is proportional to IF x duration. IF is the ratio of NP to FTP. So you can see how NP and duration rule TSS.

Corrected, but right on.

OP, ride 3 felt harder because you bonked during the ride, but TSS doesn't factor for that. Your time could have been faster due to wind, position, or other conditions on the route, but your power was significantly lower on #3.

I'm not exactly sure what you mean by optimize TSS, and I would suggest that you optimize your training instead and let the TSSs fall where they may. Riding in a certain way to produce a certain TSS is not really ideal. Aside: ride #2 suggests that your FTP might be understated, as it should be impossible to have an IF of 1.09 for 1hr 25min.

Thanks for the feedback. The numbers were mainly an inspiration for the real question: If 1h30 rides (1-4 a week, very unregular) is what I can do. How to best do them. I am not diciplined enough to do 'fancy' series of N minutes with P power repeated so and so. But, I can choose either to ride hard enough to keep 'constant' power for 1h30. Or I can start harder and then finish weaker.

ATB
Henrik

Your FTP is set to low.

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My latest power profile: 5SP: 16.3w/kg | 1MP: 7.7w/kg | 5MP 5.8w/kg | FTP 4.7w/kg
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Exactly! And training with Power is more or less without PE and speed in mind and therefore you shouldn't care if you felt worse or were quicker. All that matters is the Watts you produced. So, #3 is the "easiest" of the 3 rides.

What kind of events are you training for? The demands of the event will dictate the needs of your training program.