The dosing and spacing of speedwork sessions is extremely important.
Dosing borrows from pharmacology. The optimal training stimulus lies somewhere between a minimum effective and maximum absorbable dosage. This can only be learned through experience...but good coaching helps immensely. Because speed is the most quality-driven aspect of athleticism, we want just enough to cause adapation. But we must avoid "overdosing" because this results in burnout and breakdown.
Spacing comes in next. How far apart in a weekly microcycle we place speed training sessions is important. Those who are younger, highly competitive, and with very specific speed goals might possibly get 3-4 speed exposures in a given week. Lifetime Athletes almost always do best with only 1-2.
We build these conditions into our T2 programming. However, any Lifetime Athlete can look at readiness, recovery, and performance to determine the mixology which works ideally for their unique human BEAST.