You can program from energy systems (black box) and from power (output). But what better choice now?
Input versus output
When you train someone you usually use a training schedule. We call this scheme the input. This input affects the body. Different systems are put to work. Think of the neurological system or physiological systems. This then results in a certain performance. We call this the output. You can measure the output with, for example, the weight someone moves or the speed at which someone moves. So you measure the entire performance.
The black box
The black box, in other words the body, is a very complex thing. Different systems work at the same time and many variables influence this. It is therefore very difficult to understand very clearly why you can deliver a certain performance. This is also the case with energy systems.
Supplying energy by means of ATP
To be able to supply energy, we convert certain substances into ATP: Adenosine Triphosphate. This is the substance to be able to supply energy. There is not 1 system that creates ATP, but there are different systems, such as the anaerobic and aerobic system, that ensure that ATP is created. So there are different ATP taps with different sources that eventually end up in 1 bucket.
We use the joint ATP to be able to supply power. It is very complex to find out how big the influence is of the different taps. It is therefore much more interesting to look at the entire bucket of ATP. For example, for a marathon runner you choose to slowly pour out that bucket of energy until it is finally empty, while for a sprinter you choose to empty the bucket of energy in one go. The influence of those different ATP taps is therefore less important than the entire bucket.
We can measure how much power is consumed per unit of time. This way you can see how fast someone moves, how much weight someone moves and what distance someone bridges. When you start programming, it is very complex to individually stimulate the different variables that take place in the body.
Programming based on output
Another approach could be to base a schedule on output. You make an analysis of the sport and you look at what speed an athlete moves, what resistance that person gets and over which time unit someone has to move. Do you choose to pour out the bucket of energy quickly, a little slower or very slowly? So how do you deal with your energy and how does this relate to the sport.