# Plan template — build block (VO2 + durability + strength)

A fill-in skeleton for a **build** mesocycle that sharpens the aerobic engine while preserving the
base's durability and strength gains. A *knowledge template*, not a calculator — pull all metrics
(CTL/ATL/TSB, FTP, MAP, TSS) from the Intervals.icu MCP server; reason with the referenced docs.

## Position in the season

Build sits between base and peak (backward-mapped from the A-race — see
`assets/plan-template-base.md` and `references/periodization.md`). Its job: raise sustained power at
and above threshold, add race-specific top-end, and keep durability from base intact.

```
Weeks of build:              __________
Weeks until A-race:          __________
Current CTL / ATL / TSB:     ____ / ____ / ____   (MCP get_athlete_summary)
Primary limiter this block:  (VO2max? threshold? repeatability? — pick ONE emphasis)
Race demands:                (road/TT steady? MTB/XCO intermittent? — mtb-xco-demands.md)
```

## Mesocycle rhythm

Same as base: **3:1** (higher recoverability) or **2:1** (masters / high life stress). Build weeks
carry more *intensity*, so recovery weeks matter more, not less.

## Weekly shape (build phase)

Fewer but sharper hard sessions. **Getting enough quality hard sessions in tends to matter more
than the exact polarized-vs-pyramidal label** — a heuristic grounded in Seiler 2024, not a
quantified law (see `references/periodization.md`). A common shape:

```
VO2max session:     1–2 × /week   (see references/vo2max-intervals.md for rep length / work:rest)
Threshold / race-specific: 1 × /week   (or fold into the durability ride for MTB)
Long durability ride: 1 × ____ h with hard efforts placed LATE (references/durability.md)
Endurance / Z2:     fill remaining volume — protect the low end
Strength (maintenance): 1 × /week heavy, low volume (references/strength-for-cyclists.md)
Recovery / off:     as needed
```

### VO2max prescription (from `references/vo2max-intervals.md`)
- Goal is **maximizing time ≥90% VO2max**, not just "going hard."
- **No rep length is proven superior in cycling.** Default to **medium reps (~2–4 min, near the
  pooled ~140 s optimum)** at ~0.85 work:rest; use short (30/15 s) or long (4–5 min) by athlete and
  goal. Do not assume "longer is better" — see the modality conflict in `references/vo2max-intervals.md`.
- Prescribe from **power**; for MTB, HR will lag and mislead (`references/data-confounds.md`).

## Keep durability alive

- Maintain at least one long ride; add fatigued-state efforts late (hard work after accumulated
  kJ). Durability decays if overall load drops (Spragg et al. — `references/citations.md`).
- Re-run the durability field test (`assets/field-test-durability.md`) at block end to confirm it
  held while you added intensity.

## Preserve strength (don't drop it)

- **1×/week heavy maintenance** retains in-season strength gains; interference is muted with
  strength-first/separate-day sequencing and at older age (`references/strength-for-cyclists.md`).

## Checkpoints (pull from MCP, judge with the skill)

- [ ] VO2 sessions actually spending time ≥90% VO2max (power sustained across reps) — streams/intervals
- [ ] TSB not chronically buried — `get_athlete_summary`; screen wellness (`data-confounds.md`)
- [ ] Durability % holding or rising — `field-test-durability.md`
- [ ] Race-specific demand rehearsed (steady TT vs intermittent MTB) — `mtb-xco-demands.md`
- [ ] Strength maintained — logged sessions