Clarifying Charlie's System

Actually, it’s the opposite for L->S. The key difference between L->S and S->L is which quality is advanced ahead of the other, speed or speed endurance. While this will obviously be reflected in relative volumes of each type of training, it will also be reflected in the length of acceleration used in each one, which will determine the intensity and progression of each element. The differences between the programs are more apparent during the early phases of training in fall and winter, whereas by summer they pretty much arrive at the same place, they just got there from different directions.

For example, in a S->L program, during the first SPP you might be accelerating out to 50-60m, which will pretty much put most people at top speed. At the same time, you can include, e.g., 300m SE runs, which typically would only require a 30m acceleration to run a PB.

For a L->S program, it is reversed. You can still include short accelerations and sprints along with the SE runs. However, in addition to using less volume than for SE, you would also limit your acceleration distance in these shorter sprints to less than that used in the SE runs. That way, the development of max speed trails behind SE until you get into the outdoor season.

In other words, in S->L you accelerate farther and reach higher intesities in the short speed work before doing so in SE work. In L->S, it’s the opposite; you accelerate farther and reach higher intensities in the SE work before progressing the short speed work to maximum speed.

At least that’s my understanding. I could be wrong.