So, the implementation of W'bal in GoldenCheetah has been a bit of a challenge.
I wanted to explain what we've done and how it works in this blog post, but realised that first I need to explain the science behind W'bal, W' and CP.
W' and CP
How hard can you go, in watts, for half an hour is going to be very different to how hard you can go for say, 20 seconds. And then thinking about how hard you can go for a very long time will be different again. But when it comes to reviewing and tracking changes in your performance and planning future workouts you quickly realise how useful it is to have a good understanding of your own limits.
In 1965 two scientists Monod and Scherrer presented a ‘Critical Power Model’ where the Critical Power of a muscle is defined as ‘the maximum rate of work that it can keep up for a very long time without fatigue’. They also proposed an ‘energy store’ (later to be termed W’, pronounced double-ewe-prime) that represented a finit…
Below, in the spirit of the great continental philosophers, is a dialectic that attempts to synthesize the typical arguments that arise when debating a polarized training approach.
It is not intended to serve as an introduction to Polarized training, there are many of those in-print and online. I think that Joe Friel's blog post is a good intro for us amateurs.
Elite athletes have been shown in a number of
studies to train in a polarized manner  There
is more than one way to skin a cat.Elite athletes
adopt plans that include high-volumes of low intensity and
low-volumes of high-intensity.
Elite athletes have also been shown to train in a
Polarized Zones are between LT1/VT1 and LT2/VT2
LT1/VT1 and LT2/VT2 can be identified using a
number of field based approaches 
You can follow guidelines on
mapping LT1/LT2 to cycling power to make it useful for
Polarized zones are har…
Defining the problem
Any given training ride or race will contain periods of sustained effort, sometimes to exhaustion. Perhaps during the last sprint, or over a long climb, bridging a gap or chasing on after a roundabout or corner.
Being able to identify these efforts is rather useful.
The trouble is, deciding what represents a maximal or sustained effort is often discussed, and generally has fallen into discussions about intensity and FTP or Critical Power. These discussions have tended to then focus on trying to account for the interval duration, periods of freewheeling and applying smoothing etc.
But we already have an excellent description of what constitutes a maximal effort. It is the primary purpose of any power duration model.
Power duration models estimate the maximal effort you can sustain for any given duration through to exhaustion. So if you want to identify maximal efforts its your friend.
Using the model below we can see, for example, that the athlete it represents co…