Where do spikes on Power PR charts come from?

Quick question:
How can I have a higher 5 Min average power in a workout than the 4 Min average power? Shouldn’t the 4 Min power be equal or greater than the 5 Min average? Where does the spike on below picture come from?
Best, Moritz

Moritz: the spikes arise in the following way.
Consider a sequence of powers – say 1-minute powers: 5, 4, 4, 5, …
Now look for the best powers:
1-minute power: 5
2-minute power: 4.5
3-minute power: 4.3
4-minute power: 4.5.
Any sequence like this, where there is a high separated from another high by a valley, will generate some kind of spike, if the peaks are high enough in relation to the length of the valley.

In any one PR chart from one or a few workouts, you will get this effect. Once the PR chart reflects more workouts, the spikes disappear.

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Thanks for the reply! I still don’t completely get it. Following your example:
In one workout, how can my best 3-minute power be 4.3, if my best 4-minute power is 4.5?

To achieve a best 4-minute power of 4.5, don’t I also need a 3-minute power that is at least 4.5?

It’s the magic of structured training, and effect of varying effort over a workout.

Consider a simplified version: You spend 1 minute at 140% of FTP, then 1 minute resting at 60%, then 1 minute at 140% again.

Your 1 minute power is 140% FTP. Your 2 minute power is the average of your hard and easy interval, so 100% FTP. But your 3 minute power average of hard+easy+hard, or ~113% FTP. In this scenario, there is no continuous 2 minute interval where you average over 100% FTP, but if you expand that interval to 3 minutes you get back into a hard effort. So 3 minute>2 minute.

If you do more intervals or sets of intervals it gets even more spiky, as the pattern repeats. Here’s my chart for Bashful +2:

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Excellent explanation! Now I get it

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Thanks! I was confused by this as well. Makes more sense now!

Pettit +1 is similar to your workout. The two 20-second sprints at the end are 6 minutes apart. So the max is 6:20 as it includes both sprints. Here is a recent workout:

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