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Critical Power

What is it? Why should I use it? How do you calcaulte it.


What is it?

Critical power (CP) represents the boundary between the severe and heavy intensity domain. Between steady state and non-steady state. Each domain has physiological characteristics. We use it as an aerobic parameter of fitness. It is underpinned by type 1 muscle fibre types and capillary density around these fibres.


What is W'

The other element it provides is W' which is a set amount of work above CP that you can complete before task failure. It predicts tolerance to severe-intensity exercise. Measured in kJ.

Collectively we use these values to understand your physiology.


How to Calculate it

There are multiple methods, please see our blog on this. There are options available on WKO5, but it is very easy to do in Excel. Download the following sheet. 



 How long you can sustain it for is based on how well-trained you are. on average it's is 30-40 minutes, it has been up to 75 minutes and as low as 20

Critical Power, is the boundry between the severe in heavy insesity domain, between non steady state and steady state power. There is a vast amount of reserach on CP since its concept was first introducted in 1925.

Define good. Context is really key here and everyone has different aims. So 'good' needs to be in the scope of what your aims are. if it is at 2 w/kg and you want to aim for top 10 in Nat B road races then there is a lot of work to be done.

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What it isn't is anaerobic work capacity. W' is not as well understood as CP from the research. It's a mathamtical concept that allows us to predict tolerance to exercise in the severe intenisty domain. It correlates with both aerobic and anaerobic. We measured this and have a look on my research gate profile for the latest research on this area.

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