This principle states that when you want to achieve improved performance, the training load must necessarily exceed a certain threshold.
Intensity threshold and stimulus
For each energy process and for each physical quality there is an intensity threshold below which no functional improvement can be achieved.
This is the minimum intensity necessary to achieve a result. For example, improvement in strength can only be obtained from a certain percentage of 1RM* (80 to 85% according to the authors), and the same applies to the qualities of strength endurance, power and the development of hypertrophy.
The same applies to cardio training, below a certain percentage of the maximum oxygen consumption or VO2 max and depending on what we are looking for, no functional improvement is possible.
For example, we can speak in a very general way and according to the authors of 60 to 80% for fundamental endurance, 80 to 90% for active endurance and beyond 90% for the VMA.
Obviously this threshold depends on the level of the athlete and evolves with the progress obtained but it is always positioned at values relatively close to the maximum limits of the process that one wishes to improve.
* Max. Maximum possible load achieved on a movement.
