before starting a training session I would like to know the average watts that I will develop by setting an FTP value. I state that I do not always use the same FTP, for example when I just let legs going maybe I do a Strava workout but with an FTP much lower than the one I usually use.
The idea is to have like a prediction of the average watts at the end of the training because knowing this you will have better visibility to know how much harder and take better control of it.
Welcome to the forum.
I would not suggest using different FTP (I am not a coach), that is why there are different levels of training.
If you use the same FTP you can look at the TSS prediction of the workout that will give you a good indication of how hard it will be. 100 TSS is 1 hour at FTP. 50TSS is 30 minutes at FTP or 1 hour at 50% FTP.
Thanks @Gerrie_Delport_ODZ for your attention!
In my mind TSS might be a good indication but not an accurate prediction.
I imagine doing a 100% FTP workout at the end of 180 watts average. I like the workout but I have to do an easy ride and I would like to set the average watts of the workout to 120. How do I do it? I was thinking lowering the FTP and if I had a prediciont it would be easy to set 120Watt.
I guess I’m the only one with this need :-)!
Leave your FTP at its correct value.
Choose an appropriate workout.
Hope this helps.
Could use the workout Bias on the Companion App which adjusts the power between +/- 25%. If more range is needed build a couple of custom workouts based on the one you are using.
You should let the FTP how it’s calculated and adapt your workout to have easy wattage. Or even build your own workout and set lower values. If your FTP is like that it means that’s how your body can handle it so if you need an easy workout let it base it on your values. You can always move it up or down. It’s more precise this way…
I agree with everyone that you should not change your ftp. That said, for mathematical curiosity, the average watts scale linearly with the FTP, therefore once you have one measure of watts for one FTP value, it’s easy: watts(FTP) = knownWatts / knownFTP * FTP. For example, if you did the workout with 200 FTP and resulted in 108 average watts, doing the workout with 120 FTP will result in 180 / 200 * 120 = 183 watts. If you want to know how much FTP you should set to achieve a certain average watts, the formula is FTP(desiredWatts) = knownFTP / knownWatts * desiredWatts. For the example above, to have an averae of 120 watts, you can compute FTP = 200 / 180 * 120 = 133. Again, we encourage you not to change your FTP, but you can use this computations to create “scaled” copies of your favourite workouts with perfect prediction of the resulting average watts (until you actually change your FTP).
I hope I did the math correctly. Ride on!