Power Duration Curve explained
The power duration curve represents your best efforts (in Watts) over a given duration within the last 90 days, and in theory, represents your max ability over a given duration. It is made up of segments, with each segment being tied to an associated run.
The power duration curve and your Critical Power are closely related, with your CP being modeled from your best effort runs.
The more you continually push your max power in the short, middle, and long durations, the higher your CP will move.
Note not every best effort that changes your power duration curve will change your critical power because your CP is a theoretical model based on your power duration curve.
Why default to the last 90 days?
We default to showing the last 90 days because it best represents the period of time that contributes to your Critical Power based on our model for determining CP.
Specifically, if you are not training, 90 days is long enough to capture the effects of detraining, and if you are training, it's long enough to cover the key part of your training plan (e.g., build-up phase and peak phase).
If shorter than 90 days, we may miss some of the training/detraining effects and accumulated adaptation.
Here are some resources to explain the effects of training and detraining...
Geeky explanation: https://link.springer.com/article/10.2165/00007256-200030020-00002
Why don’t you show the modeled curve?
We plan to! It will be in a future update.