# Periodization, distribution & taper

**Load this doc when:** structuring a season, choosing an intensity distribution, setting a CTL
ramp, or planning an A-race taper.

**Data/knowledge split:** MCP supplies CTL / ATL / TSB, the load ramp, and TSS. This doc supplies
the logic for *how fast to ramp*, *how to distribute intensity*, and *what TSB to target*.

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## Distribution is a principle, not a recipe

Do not treat polarized (or pyramidal) training as a fixed formula. The right distribution is
**context-dependent** — set by training age, weekly volume, life stress, and the current phase.

The framing to internalize: effective endurance training is **"the long game, not epic workouts."**
HIIT should not be prescribed as an acute-response "maximization problem"; what matters is the
**long-term integration** of intensity, duration, and **frequency**, adapted to the athlete's
context (Seiler 2024, *Appl Physiol Nutr Metab* 49(11):1585–1599; PMID 39079169;
DOI 10.1139/apnm-2024-0012 — a peer-reviewed Perspective, open access).

**On "frequency matters more than the exact distribution":** this is a reasonable working heuristic
consistent with Seiler's long-game argument, but note the honest state of evidence — a 2025 review
of training-intensity-distribution models concludes **no single model is universally superior** and
that model choice must be adapted to sport, phase, and athlete (Sun, Yu et al. 2025, *Front Physiol*
16:1657892; PMID 41169886; DOI 10.3389/fphys.2025.1657892). Treat "get enough quality hard sessions
in, don't obsess over polarized-vs-pyramidal labels" as a defensible principle, **not** a
quantified finding.

> **Citation honesty note:** a specific "Yu et al. 2025" paper claiming *frequency of hard sessions
> outweighs distribution* could **not** be located in PubMed. Do not cite one. Ground the point in
> Seiler 2024 (the long-game argument) and the Sun/Yu 2025 review (no model universally superior).
> See `citations.md`.

## Standard periodization: base → build → peak

Work **backward from the A-race** (backward mapping). Each phase sets up the next.

| Phase | Primary job | Emphasis |
|---|---|---|
| **Base** | Raise sustainable CTL, aerobic base, **durability**, and strength capacity | High volume, mostly low intensity, small hard dose kept alive; build heavy strength |
| **Build** | Sharpen threshold & VO2max; add race-specific top-end; preserve durability & strength | Fewer, sharper hard sessions; strength → maintenance |
| **Peak/Taper** | Shed fatigue, keep fitness, arrive fresh | Reduce volume, keep some intensity, hit TSB target |

Templates: `../assets/plan-template-base.md`, `../assets/plan-template-build.md`.

## Mesocycle rhythm

| Athlete | Rhythm | Note |
|---|---|---|
| Younger / high recoverability | **3:1** (3 load weeks : 1 recovery) | Standard |
| **Masters / higher life stress** | **2:1** (2 load : 1 recovery) | Favor recovery — masters recover slower; the 2:1 protects adaptation |

Recovery weeks ≈ 40–60% of the preceding load week's TSS. These are *adaptation* weeks, not lost
time — the fitness is expressed during them.

## CTL ramp guidance

- Ramp **CTL gradually** — a common, conservative guide is **~3–7 CTL points per week** sustained,
  lower for masters or when life stress is high. Faster ramps raise injury/illness/overtraining
  risk without proportional benefit.
- Read the actual CTL/ATL/TSB and ramp rate from MCP (`get_athlete_summary`); this doc only tells
  you whether the ramp is sane. A runaway ramp with a deeply negative TSB trend is a flag — cross-
  check wellness before pushing (`data-confounds.md`).

> ⚠️ **The CTL ramp numbers are heuristics, not laws.** Individual tolerance varies widely —
> **track response** (wellness, performance, durability) rather than forcing a fixed points/week.

## A-race taper & TSB targets

- **Goal:** arrive with fitness intact and fatigue gone — a **positive but not deeply detrained
  TSB**. A common target window is **TSB ≈ +5 to +15** on race day (higher for shorter/punchier
  events where freshness dominates; lower for long events where fitness retention matters more).
- **How:** cut **volume** substantially over the final 1–2 weeks while **keeping some intensity**
  (short race-specific efforts) so you sharpen rather than go flat. Don't cut intensity to zero.
- **Durability caveat:** durability decays if load drops too far for too long (`durability.md`). For
  long/marathon events, taper less aggressively than for short punchy events, or you arrive fresh
  but unable to hold late-race power.
- Read TSB from MCP and steer it into the target window; this doc sets the target, MCP measures it.

> ⚠️ **Taper TSB targets are individual.** The +5 to +15 window is a starting point; some riders
> peak flat at +5, others need +15–20. **Track how the athlete has raced at known TSB values** and
> personalize.