Your power records were probably obtained when you were on top form. However, when you return to training after a period of rest, your fitness levels have potentially reduced. It is unwise to always refer back to your personal bests to build and construct your training plan. If we only ever used our personal best scores, we run the risk of working outside of our current intensity zones and overtraining. With your power and heart rate data we are able to assess your current potential critical power levels so that you can adapt your training zones as efficiently as possible.
The ‘estimated critical power’ is therefore an estimate of the critical power you would get if you were to do a test on that day.