- Periodization organizes training stimuli over time.
- Earlier phases build capacity; race-specific work gains importance later.
- No phase should override recovery, training history or actual execution.
What periodization actually means
Periodization means that training does not look identical every week. Over weeks and months, the emphasis on mileage, easy running, threshold work, faster intervals, long runs and race specificity changes.
The important idea is not one rigid phase model. It is that different goals need different stimuli at different times.
Why there is no single “optimal week”
A workout can be useful in isolation and still be poorly timed. Long HM-specific blocks matter most once enough aerobic and mechanical capacity exists to tolerate them. Likewise, progression does not always mean more kilometers. It can mean more specific work at similar volume or better control at the same pace.
Periodization is not a staircase
Research does not identify one perfect weekly sequence for everyone. Reviews describe pyramidal, polarized and threshold-heavy models. The overall picture argues against making moderately hard running the default every day and supports a large base of low-intensity work with deliberately placed stronger stimuli.
Race date gives direction; real training decides the next step.
PACE assigns training priorities to a phase and changes the permitted workout mix over time. Recovery, available training days, demonstrated volume capacity and actual completed sessions remain authoritative, so a planned phase never forces a stimulus that no longer fits the real week.
How to recognize sensible periodization
You should be able to explain why a workout appears now. The plan should allow progression without demanding an increase every week, and it should become more race-specific without losing the foundation that made that specificity possible.