How to Structure Workouts

If all you're doing is consistently being like, it's gold an glory or naught else, then what happens, and i've seen this so many times, is you just set yourself up where it's like boom or bust. Oftentimes we think of races as this cumulative thing. But it's like let's look at the sections of it. How is that athlete handling the different sections? And that might tell you where a, the a lack of fitness on whatever level, mental, emotional, physiological lives.