Periodization

Periodization is the deliberate structuring of training into phases that progress toward a goal — classically base, build, peak/specific-prep, and taper — organized across nested time scales. The premise is that you can't hold peak fitness or train every quality at once, so you sequence blocks that develop general fitness first and race-specific sharpness last. It's the scaffolding that turns a pile of workouts into a plan.

Nested time scales:
    Macrocycle  — a whole season / to a goal event (months)
    Mesocycle   — a training block or phase (≈ 3–6 weeks)
    Microcycle  — typically one week

Modern periodization is usually traced to Leo Matveyev's systematization of Soviet training theory in the 1960s. The traditional model moves from high-volume, low-intensity base work (building the aerobic engine) through a build phase that layers in threshold and VO2max intensity, into a specific/peak phase that sharpens race-relevant abilities, and finally a taper that sheds fatigue for the event. Volume and intensity trade off across the arc — lots of easy volume early, less-but-harder work later.

Traditional (linear) periodization develops several qualities concurrently with a gradually shifting emphasis. Block periodization, associated with Issurin, instead concentrates a small number of training targets into focused blocks, exploiting the residual training effects of previously-developed qualities so one is trained intensively while others are merely maintained. Block approaches suit time-crunched and already-trained athletes; the honest reading is that both work, and the choice depends on the athlete, the calendar, and the event.

The nested cycles carry real weight: microcycles (usually a week) alternate load and recovery days; mesocycles (a few weeks) group microcycles into a phase, typically closing with a recovery week to consolidate; the macrocycle spans the season to the A-race. The common mistakes are skipping the base entirely, never de-loading (no recovery weeks inside a mesocycle), and peaking too early or with no taper at all. Periodization is precisely what stops a year of undifferentiated sweet spot from plateauing.