Yes, endurance work does improve aerobic en-
durance, and sprinting does improve sprinting and
short-term speed. At the same time, though, sprint-
ing also improves aerobic endurance. That’s killing
two birds with one stone: running sprints improves
the endurance capacity in all muscle fibers, not
just the fast ones, while low-intensity aerobic exer-
cise only targets the slow twitch fibers. I’ll always
encourage everyone to Move Frequently at a Slow
Pace as a foundation for Primal Blueprint Fitness,
mind you, but it’s clear that any functional fitness
regimen is incomplete without a sprint dynamic.
There’s nothing wrong, remember, with a shortcut
that doesn’t shortcut results. Sprinting is simply an
efficient, effective way to target your fast twitch,
type II muscle fibers without spending a ton of
time in the gym and improve slow twitch efficiency
at the same time.
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