You can only really exert a sprint-effort at anything if you come from a place of rest.
A boxer is completely relaxed before striking.
Brilliant ideas don’t come from extended periods of mild focus, but rather all at once in a burst, typically from a relaxed state.
Type II muscle fibers (fast twitch) can only sustain a short burst of energy all at once, and to deliver 100% of that burst they have to start fully relaxed.
If there’s slack in your system, and you get good amounts of downtime, you’re probably far better equipped to sprint when it really counts – as long as you practice regular sprints.
If the system is tight, however, you’re probably stuck at a 6-7 intensity, and virtually unable to extend to an 8, let alone a full on 10/10 sprint.