12. The Principle Of Intentional Progression

What is intentional progression?
'Intention' in this context is referring to the target muscle group of an exercise.
'Progression' is the scaling of load. 
Therefore, intentional progression is a principle of scaling load on the target muscle group in a reformer exercise. Every movement layer added to an exercise must contribute to an incremental increase in load. In other words, every movement layer added must make the client fatigue faster.