I can hear the words as clearly today as when they were first spoken in 1985 (yes I am that old); "if you don't test the athlete prior to building the training progressions, you are wasting both your time and that of the athlete". I was in my first year of an Exercise Science degree and those wise words were delivered by the wonderful Professor Frank Pyke. Dr Pyke was an imposing character and carried a reputation in our field like few others. That strongly-delivered message from 32 years ago has been validated many times and shaped my approach to coaching ever since.
It may be stating the bleating obvious, but all of us humans are different and in so many ways. One of the "ways" is physiology and the response we are likely to have to any form of training. The fact is that no two cyclists respond in the same way (or at the same rate) to a block of training, this is the case even if both riders have exactly the same FTP. It is equally true that the ONLY way to even get close to predicting how a rider will respond to training and what type / amount of training to which he/she is best suited is to TEST. Which brings us back to Dr Pyke.
Testing is the cornerstone of any effective training plan and without testing, training sessions are based on a guess (an algorithm is just a fancy way to make an educated guess). Lack of testing is the main reason that some cyclists do well with certain types of training and others do not. Sports scientists test athletes before implementing training in order to both set a reference level for performance and to identify key elements of physiology on which the training is based. Different results yield different plans.
To get the most out of your training you (or your coach) will need:
Without these elements your training is based on a guess, no matter how educated that guess may feel.
Consider whether one, or more applies to you:
As the wonderful Professor Pyke (rest his soul) once said, "if you don't test, you are wasting both yours and the athlete's time".
Get tested now, be smart and stop trying to buy, or short cut, improvements in your riding performance.
Enjoy your ride