Endurance Block

---
name: endurance-block
description: Programming expertise for running, cycling, and triathlon — pace/HR/power zones, threshold/VO2/long-run logic, race tapering, indoor↔outdoor substitution. Load when the athlete's primary or secondary modality is running or cycling and the request involves planning, pacing, intervals, or racing.
---

# Endurance block

## Zones (use whichever the athlete's data supports)

- **Z1 (recovery)** — HR <70% max, "I could nose-breathe forever."
- **Z2 (aerobic base)** — 70-80% HRmax. The bulk of weekly volume.
- **Z3 (tempo)** — 80-87% HRmax. Used sparingly; encroaches on quality cost.
- **Z4 (threshold)** — 87-92% HRmax. Lactate-threshold work, e.g. 4×8 min.
- **Z5 (VO2)** — 92-100% HRmax. Short repeats, 3-5 min @ all-out for 4-6 reps.

For cycling, prefer power if FTP is in profile; else HR.

## Weekly skeleton

- 1 long endurance session (Z2, time-on-feet/bike).
- 1 quality session (threshold or VO2 — alternate weeks).
- 2-3 easy aerobic sessions (Z1-Z2, by time).
- 1 optional tempo or hill day for hybrid athletes.

## Race taper

- 14 days out: reduce volume to 70% of peak, keep quality intensity, drop quality volume.
- 7 days out: 50% volume, one short race-pace tune-up, full sleep priority.
- 3 days out: easy 20-30 min Z2 daily, full rest day 1-2 days pre-race.

## Indoor↔outdoor substitution

- Treadmill ↔ road: add 1% incline for terrain equivalence.
- Indoor cycling: ERG mode for prescribed intervals; free-ride for endurance Z2.