Power data question

When doing a 20minute time trial for power data. I know if done on an uphill gradient it will increase your output. How valid should this measurement be used in training? Now of course one must work harder in workouts to maintain certain % of FTP. Should I not do uphill TT tests? but rather flat TT’ for testing?
I have a PowerTap meter on my road bike and thats what I used today on an uphill Timed effort.
I have previously used it on my TT bike for more tt based workouts.

I have read a few books for testing but none that I have read discuss uphill or not, but usually a trainer method, for control purposes. but uphill, no traffic, no lights, and using POWER as the data to be analyzed who cares.
Thanks

It doesn’t increase your power output, it’s just some people find it easier to go hard on an uphill and for people who live in hillier areas, it’s the only option for a longish test.

Many people can adapt and do similar outputs on the flat and hills and some people are the opposite of what you experienced.

Thanks
So, I should be able to put out the same wattage on a good flat course, as I do going uphill.
Thanks for your thoughts. I will continue to test and apply this with the TT bike both flat and slight uphill

I agree with the above post and I’d like to add to it that one of the best things about using a powermeter is learning of that discrepency between power on uphills vs. power on flat/downhill sections and teaching yourself to eliminate the weak spots. When I started using it, my wattage would drop dramatically on even the slightest downhills, but once I figured out some mental cues to keep pushing myself, I quickly learned how to maintain much more evenly-balanced power (and faster overall speed).

Not all power is created equal… Power is angular velocity * torque…Therefore, cadence is in the equation. Your bodies lactate response is different for different cadences. Therefore, you may be able to average a higher wattage at a lower cadence or visa versa depending on how you train. Given the same cadence there should not be a difference between what you can do up hill or flat.