docs: cross-link general docs to the discipline demand docs

Tighten the router so race-specific reasoning in the general docs points to
the matching demand profile instead of speaking in a road/TT-default voice:

- periodization.md: anchor the build phase's 'race-specific top-end' to the
  matching demand doc (tt / road-racing / mtb-xco).
- durability.md: show how fatigue resistance manifests per discipline.
- data-confounds.md: extend the intermittent-HR caveat to road racing/crits;
  note TT as the steadier exception where HR is more usable.
- strength-for-cyclists.md: link the explosive/sprint transfer to road-racing
  and sustained-power transfer to TT.
- vo2max-intervals.md: match rep length to event (short=surges/road+MTB,
  long=sustained/TT); extend the HR caveat to road racing.

All internal links verified resolving.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TqrhBhC3GEcKyaw8RTk8G6

README.md

@@ -36,6 +36,8 @@ cycling-training/
 ├── references/
 │   ├── durability.md             # Fatigue resistance as a trainable quality + field test
 │   ├── mtb-xco-demands.md        # MTB/XCO demand profile; power governs, HR caveat
+│   ├── road-racing-demands.md    # Mass-start road/crit: stochastic power, drafting, sprint
+│   ├── tt-demands.md             # Time trial: aerodynamics/CdA, critical power, pacing
 │   ├── strength-for-cyclists.md  # Heavy strength; masters rationale; from-zero ramp
 │   ├── vo2max-intervals.md       # Maximizing time ≥90% VO2max; work:rest; rep length
 │   ├── periodization.md          # Distribution philosophy; base/build/peak; CTL ramp; taper

SKILL.md

@@ -38,6 +38,8 @@ calculators by design — only periodization logic, workout design, protocols, a
 |---|---|
 | **Fatigue resistance / durability** — training it, why fatigued-state power matters, the field test | `references/durability.md` |
 | **MTB / XCO** — race demands, why power (not HR) governs off-road, marathon vs lap XCO | `references/mtb-xco-demands.md` |
+| **Road racing** — mass-start road/criterium demands, stochastic power, drafting, fatigued sprint | `references/road-racing-demands.md` |
+| **Time trial** — sustained solo effort, aerodynamics/CdA, critical power, TT pacing | `references/tt-demands.md` |
 | **Strength training** — heavy lifting for cyclists, masters muscle loss, from-zero ramp, in-season | `references/strength-for-cyclists.md` |
 | **VO2max / high-intensity intervals** — rep length, work:rest, maximizing time ≥90% VO2max | `references/vo2max-intervals.md` |
 | **Season structure** — base/build/peak, mesocycles, CTL ramp, A-race taper & TSB targets, polarized vs pyramidal | `references/periodization.md` |

references/citations.md

@@ -80,6 +80,98 @@ Fransen J, Dascombe BJ. *Predictors of performance in a 4-h mountain-bike race.*
 
 ---
 
+## Road-racing demands (mass-start / criterium)
+
+**✅ Vogt et al. 2007** — TdF mass-start mean power only ~3.1–3.3 W/kg (218–234 W) despite decisive
+higher efforts; stochastic profile. Vogt S, Schumacher YO, Roecker K, Dickhuth H-H, Schoberer U,
+Schmid A, Heinrich L. *Power Output during the Tour de France.* Int J Sports Med. 2007;28(9):
+756–761. **PMID 17497569 · DOI 10.1055/s-2007-964982.**
+
+**✅ Ebert et al. 2006** — pro men's tour: low mean power with repeated surges above maximal aerobic
+power. Ebert TR, Martin DT, Stephens B, Withers RT. *Power output during a professional men's
+road-cycling tour.* Int J Sports Physiol Perform. 2006;1(4):324–335. **PMID 19124890 ·
+DOI 10.1123/ijspp.1.4.324.**
+
+**✅ Ebert et al. 2005** — women's World Cup power-output profile (SRM). Ebert TR, Martin DT,
+McDonald W, Victor J, Plummer J, Withers RT. *Power output during women's World Cup road cycle
+racing.* Eur J Appl Physiol. 2005;95(5–6):529–536. **PMID 16151832 · DOI 10.1007/s00421-005-0039-y.**
+
+**✅ Sanders & van Erp 2021** — updated review: demands strongly shaped by stage/race type. Sanders
+D, van Erp T. *The Physical Demands and Power Profile of Professional Men's Cycling Races: An Updated
+Review.* Int J Sports Physiol Perform. 2021;16(1):3–12. **PMID 33271501 · DOI 10.1123/ijspp.2020-0508.**
+
+**✅ van Erp & Sanders 2021** — 2,920 files / 20 pros: demands vary by race category and result.
+van Erp T, Sanders D. *Demands of professional cycling races: Influence of race category and result.*
+Eur J Sport Sci. 2021;21(5):666–677. **PMID 32584197 · DOI 10.1080/17461391.2020.1788651.**
+
+**✅ Blocken et al. 2018** — CFD + wind tunnel: peloton drag drops to ~5–10% of an isolated rider.
+**No PMID — cite by DOI** (journal not MEDLINE-indexed). Blocken B, van Druenen T, Toparlar Y,
+Malizia F, Mannion P, Andrianne T, Marchal T, Maas G-J, Diepens J. *Aerodynamic drag in cycling
+pelotons: New insights by CFD simulation and wind tunnel testing.* J Wind Eng Ind Aerodyn.
+2018;179:319–337. **DOI 10.1016/j.jweia.2018.06.011.**
+
+**✅ Menaspà et al. 2015** — pro road sprint peak ~17.4 ± 1.7 W/kg, preceded by high-intensity
+lead-in. Menaspà P, Quod M, Martin DT, Peiffer JJ, Abbiss CR. *Physical Demands of Sprinting in
+Professional Road Cycling.* Int J Sports Med. 2015;36(13):1058–1062. **PMID 26252551 ·
+DOI 10.1055/s-0035-1554697.**
+
+**✅ Menaspà, Abbiss & Martin 2013** — world-class sprinter Grand Tour performance analysis.
+Menaspà P, Abbiss CR, Martin DT. *Performance analysis of a world-class sprinter during cycling
+grand tours.* Int J Sports Physiol Perform. 2013;8(3):336–340. **PMID 23038704 ·
+DOI 10.1123/ijspp.8.3.336.**
+
+**✅ van Erp, Sanders & Lamberts 2021** — maintaining maximal power after high accumulated work is a
+key success determinant (durability in road racing). van Erp T, Sanders D, Lamberts RP. *Maintaining
+Power Output with Accumulating Levels of Work Done Is a Key Determinant for Success in Professional
+Cycling.* Med Sci Sports Exerc. 2021;53(9):1903–1910. **PMID 33731651 ·
+DOI 10.1249/MSS.0000000000002656.**
+
+**✅ Etxebarria et al. 2019** — ~1 h prior stochastic cycling cut a subsequent 30 s sprint ~5–6%
+(criterium/finish relevance). Etxebarria N, Ingham SA, Ferguson RA, Bentley DJ, Pyne DB. *Sprinting
+After Having Sprinted: Prior High-Intensity Stochastic Cycling Impairs the Winning Strike for Gold.*
+Front Physiol. 2019;10:100. **PMID 30837886 · DOI 10.3389/fphys.2019.00100.**
+
+---
+
+## Time-trial demands
+
+**✅ Crouch et al. 2017** — review: aerodynamic drag dominates at racing speeds; the rider is ~80% of
+system drag. Crouch TN, Burton D, LaBry ZA, Blair KB. *Riding against the wind: a review of
+competition cycling aerodynamics.* Sports Eng. 2017;20(2):81–110. **DOI 10.1007/s12283-017-0234-1.**
+> The popular "~90% of power to aero at 40 km/h" soundbite traces to **Kyle & Burke 1984**
+> (*Mechanical Engineering*, a trade magazine — **not MEDLINE-indexed, unverifiable, do not cite as
+> primary**). Use Crouch 2017 or Martin 1998 as the verifiable anchor and treat the exact % as
+> approximate.
+
+**✅ Martin et al. 1998** — validated mathematical model of road cycling power (R²=0.97); aero
+dominates on the flat. **No PMID — cite by DOI** (journal not PubMed-indexed). Martin JC,
+Milliken DL, Cobb JE, McFadden KL, Coggan AR. *Validation of a Mathematical Model for Road Cycling
+Power.* J Appl Biomech. 1998;14(3):276–291. **DOI 10.1123/jab.14.3.276.**
+
+**✅ García-López et al. 2008** — wind-tunnel position changes cut pro cyclists' drag ~14%; CdA is
+the primary TT lever. García-López J, Rodríguez-Marroyo JA, Juneau C-E, Peleteiro J, Córdova
+Martínez A, Villa JG. *Reference values and improvement of aerodynamic drag in professional
+cyclists.* J Sports Sci. 2008;26(3):277–286. **PMID 17943597 · DOI 10.1080/02640410701501697.**
+
+**✅ Swain 1997** — vary power on hills/wind (higher into climbs/headwinds) to save TT time. Swain
+DP. *A model for optimizing cycling performance by varying power on hills and in wind.* Med Sci
+Sports Exerc. 1997;29(8):1104–1108. **PMID 9268969 · DOI 10.1097/00005768-199708000-00017.**
+
+**✅ Atkinson, Peacock & Passfield 2007** — updated model: variable pacing on terrain/wind saves
+time; even power near-optimal on flat/windless. Atkinson G, Peacock O, Passfield L. *Variable versus
+constant power strategies during cycling time-trials: prediction of time savings using an up-to-date
+mathematical model.* J Sports Sci. 2007;25(9):1001–1009. **PMID 17497402 · DOI 10.1080/02640410600944709.**
+
+**✅ Smith, Dangelmaier & Hill 1999** — critical power predicts 17-km/40-km TT (r = −0.77 to −0.91),
+more than VT or VO2max. Smith JC, Dangelmaier BS, Hill DW. *Critical power is related to cycling time
+trial performance.* Int J Sports Med. 1999;20(6):374–378. **PMID 10496116 · DOI 10.1055/s-2007-971147.**
+
+*(TT durability draws on Maunder et al. 2021 — see the Durability section above. A dedicated,
+verified HR-reliability-in-TT citation was sought but not confirmed; TT HR guidance defers to
+`data-confounds.md` rather than resting on an unverified source.)*
+
+---
+
 ## Strength training (incl. masters)
 
 **✅ Llanos-Lagos et al. 2026 (epub 2025)** — meta-analysis, 17 studies / 262 cyclists: heavy

references/data-confounds.md

@@ -16,8 +16,10 @@ factors. Use HR only where it is genuinely informative:
 - **Aerobic decoupling on steady rides** (Pw:HR drift) — valid only on steady efforts.
 - **Recovery trends** (RHR, HRV) — as *trends*, screened for the confounds below.
 
-Do **not** use HR to prescribe or judge intensity for **intermittent** efforts — see the MTB
-dissociation below.
+Do **not** use HR to prescribe or judge intensity for **intermittent** efforts — this covers MTB
+(`mtb-xco-demands.md`) *and* mass-start road racing/criteriums (`road-racing-demands.md`), both of
+which are surge-driven. See the dissociation below. Steady solo efforts (TT — `tt-demands.md`) are
+the exception where HR is more usable, though still secondary to power.
 
 ## The confounds (screen every HR-based signal against these)
 
@@ -38,7 +40,8 @@ In intermittent off-road riding, **HR, power, and VO2 dissociate**: VO2 stays el
 where power drops, and HR lags the short bursts that define the effort. In XCO, %VO2max did **not**
 correlate with %HRmax or %MAP (Hays et al. 2018, *Front Physiol* 9:1062; PMID 30158873;
 DOI 10.3389/fphys.2018.01062). **For MTB, HR is unreliable for intensity — power governs.** See
-`mtb-xco-demands.md`.
+`mtb-xco-demands.md`. The same intermittent logic applies to mass-start road racing and criteriums
+(`road-racing-demands.md`): HR lags the decisive surges, so prescribe and read those from power too.
 
 ## Do NOT hardcode naive rules
 

references/durability.md

@@ -72,5 +72,7 @@ Use `../assets/field-test-durability.md`. In brief:
 
 Durability matters for both road/TT and MTB, but **keep absolute numbers discipline-specific.** The
 1,500 kJ anchor is a sensible generic default, not a validated cross-discipline constant; a masters
-marathon-MTB rider and an elite road pro do not share a durability dose. See `mtb-xco-demands.md`
-for how fatigue resistance shows up specifically in off-road racing.
+marathon-MTB rider and an elite road pro do not share a durability dose. How fatigue resistance
+*shows up* differs by discipline: `mtb-xco-demands.md` (holding power through late off-road bursts),
+`road-racing-demands.md` (still having a sprint or matching-move after 4 h — a documented success
+determinant), and `tt-demands.md` (a long-TT threshold that doesn't decay to the line).

references/periodization.md

@@ -36,6 +36,12 @@ quantified finding.
 
 Work **backward from the A-race** (backward mapping). Each phase sets up the next.
 
+**Anchor the plan to the A-race's demand profile** — the "race-specific top-end" of the build phase
+means different things per discipline. Load the matching demand doc before shaping the build:
+`references/tt-demands.md` (sustained solo power, pacing), `references/road-racing-demands.md`
+(repeatable supra-threshold surges + a fatigued sprint), or `references/mtb-xco-demands.md`
+(intermittent, supra-MAP bursts). Don't build a TT engine for a criterium, or vice versa.
+
 | 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 |

references/road-racing-demands.md

@@ -0,0 +1,99 @@
+# Road-racing demands (mass-start: road races & criteriums)
+
+**Load this doc when:** planning for a mass-start road race or criterium — any bunch event decided
+by positioning, surges, and a finish, rather than a steady solo effort.
+
+**Data/knowledge split:** MCP gives you the power streams, record power profile, and load. This doc
+explains the *demand profile* — why road racing is stochastic, what wins it, and how to train for it.
+
+**Contrast with the other demand docs:** a road race is the near-opposite of `tt-demands.md`. It is
+**intermittent, stochastic, tactical, and drafting-dominated** — structurally closer to XCO
+(`mtb-xco-demands.md`) than to a TT. Don't pace a road race like a TT; the winning move is a short
+supra-threshold effort off a variable base, not an even wattage.
+
+---
+
+## The power profile: low mean, high variance, decisive surges
+
+Mass-start road racing has a **stochastic power-output profile** — long stretches at modest power
+(sheltered in the bunch) punctuated by repeated short efforts *above* maximal aerobic power.
+
+- Across 148 Tour de France mass-start stages, mean power was only ~**3.1–3.3 W/kg** (218–234 W)
+  despite the racing being decided by far higher climb and attack efforts (Vogt et al. 2007,
+  *Int J Sports Med* 28(9):756–761; PMID 17497569; DOI 10.1055/s-2007-964982).
+- Professional tour racing showed **relatively low mean power interspersed with multiple
+  high-intensity surges above maximal aerobic power**, varying by race type (Ebert et al. 2006,
+  *Int J Sports Physiol Perform* 1(4):324–335; PMID 19124890; DOI 10.1123/ijspp.1.4.324; women's
+  World Cup: Ebert et al. 2005, *Eur J Appl Physiol* 95(5–6):529–536; PMID 16151832;
+  DOI 10.1007/s00421-005-0039-y).
+- Demands are **strongly shaped by stage/race type and by result** — flat stages load
+  short-duration maximal mean power, mountain stages load sustained efforts; higher race category
+  and better placings carry distinct intensity signatures (Sanders & van Erp 2021 review,
+  *Int J Sports Physiol Perform* 16(1):3–12; PMID 33271501; DOI 10.1123/ijspp.2020-0508; van Erp &
+  Sanders 2021, 2,920 files / 20 pros, *Eur J Sport Sci* 21(5):666–677; PMID 32584197;
+  DOI 10.1080/17461391.2020.1788651).
+
+**Training implication:** average power under-describes a road race. Train the **full record power
+profile** — repeated 10 s–5 min supra-threshold efforts off fatigue — not just steady threshold.
+
+## Drafting changes everything
+
+Sitting in the bunch is not optional physics — it's the sport. In a tightly packed peloton, drag on
+riders mid-to-rear drops to roughly **5–10% of an isolated rider's** (Blocken et al. 2018,
+*J Wind Eng Ind Aerodyn* 179:319–337; DOI 10.1016/j.jweia.2018.06.011; **no PMID — cite by DOI**).
+
+**Implications:**
+- Watts spent out of the draft (attacking, chasing, riding the front, wind-exposed) cost multiples
+  of watts spent sheltered — **positioning is a physiological lever, not just tactics.**
+- The record that matters is what you can produce *after* hours of surge-and-soft-pedal, not fresh.
+
+## The finish: sprinting after a hard race
+
+Most road races and criteriums are decided by a short, very high-power finish thrown *after* the
+race has already emptied the tank.
+
+- Professional road sprints reached peak power of **~17.4 ± 1.7 W/kg**, and power/cadence/speed rose
+  significantly in the **final minutes before** the sprint — the sprint is launched off a
+  high-intensity lead-in, not from rest (Menaspà et al. 2015, *Int J Sports Med* 36(13):1058–1062;
+  PMID 26252551; DOI 10.1055/s-0035-1554697; sprinter performance analysis: Menaspà, Abbiss &
+  Martin 2013, *Int J Sports Physiol Perform* 8(3):336–340; PMID 23038704; DOI 10.1123/ijspp.8.3.336).
+- **Prior stochastic high-intensity cycling impairs the finishing sprint:** ~1 h of variable
+  cycling cut subsequent 30 s sprint peak and mean power by **~5–6%** vs constant-power riding
+  (Etxebarria et al. 2019, *Front Physiol* 10:100; PMID 30837886; DOI 10.3389/fphys.2019.00100) —
+  directly relevant to criteriums and to any bunch finish.
+
+**Training implication:** train **sprints in a pre-fatigued state**, not just fresh — the race-day
+sprint is a fatigued sprint. This pairs with the fatigued-state work in `durability.md`.
+
+## Durability decides who is there at the end
+
+Maintaining maximal power *after* high accumulated work is a **key determinant of success** in pro
+racing: category-1 climbers and sprinters showed smaller declines in discipline-specific maximal
+mean power after heavy accumulated work than lesser riders (van Erp, Sanders & Lamberts 2021,
+*Med Sci Sports Exerc* 53(9):1903–1910; PMID 33731651; DOI 10.1249/MSS.0000000000002656). This is
+the same durability quality profiled in `durability.md` (Muriel 2022; Spragg 2023) — in road racing
+it manifests as *still having a sprint or a matching-move after 4 hours.*
+
+## Criterium vs road race
+
+Both are intermittent, but criteriums are **shorter, more relentlessly repetitive** (constant
+corner-surge-brake cycles, little true recovery), while road races add **sustained climbs and longer
+selective efforts**. The peer-reviewed criterium-specific literature is thin — the strongest indexed
+evidence is the intermittent-effort → impaired-sprint mechanism above (Etxebarria 2019); much
+criterium-vs-road detail lives in reviews (Sanders & van Erp 2021) rather than dedicated studies.
+> ⚠️ **Gap flag:** treat criterium-specific numbers as under-documented; reason from the
+> intermittent-effort principles here and verify against the athlete's own race files via MCP.
+
+## HR is unreliable here — power governs
+
+Like MTB (`mtb-xco-demands.md`), road racing is intermittent: **HR lags the surges** that decide the
+race and drifts over hours. **Prescribe and read intensity from power**; use HR only for steady
+sections and recovery trends, screened for the confounds in `data-confounds.md`.
+
+## Practical emphasis (reason here, pull data from MCP)
+
+- [ ] **Repeatability** of supra-threshold efforts — train repeated 30 s–5 min efforts off fatigue
+- [ ] **Fatigued sprint** — practice the finish pre-tired, not just fresh (Etxebarria 2019)
+- [ ] **Durability** — hold power after accumulated kJ (`durability.md`; van Erp 2021)
+- [ ] **Positioning** treated as an energy-saving skill (Blocken 2018), not an afterthought
+- [ ] Judge intensity by **power**, not HR (`data-confounds.md`)

references/strength-for-cyclists.md

@@ -84,4 +84,6 @@ failure-limited) to protect joints and recovery.
 - **Build/in-season**: drop to **1×/week heavy maintenance** — see
   `../assets/plan-template-build.md`.
 - Strength supports the **anaerobic/explosive** side that predicts MTB/XCO performance
-  (`mtb-xco-demands.md`) and the efficiency that helps steady TT power.
+  (`mtb-xco-demands.md`) and powers the **road-racing sprint and repeated surges**
+  (`road-racing-demands.md`), plus the efficiency and sustained-power that help the **TT**
+  (`tt-demands.md`).

references/tt-demands.md

@@ -0,0 +1,88 @@
+# Time-trial (TT) demands
+
+**Load this doc when:** planning for an individual time trial, prologue, or any sustained
+solo effort against the clock (road TT, triathlon bike leg, "the race of truth").
+
+**Data/knowledge split:** MCP gives you power, critical-power/FTP, and the ride streams. This doc
+explains the *demand profile* — what actually limits a TT and how to pace and prepare for it.
+
+**Contrast with the other demand docs:** a TT is the near-opposite of `mtb-xco-demands.md` and
+`road-racing-demands.md`. Those are intermittent, stochastic, and tactical; a TT is **steady,
+solo, and self-paced** — a quasi-time-invariant effort where physiology, aerodynamics, and pacing
+discipline decide the result, not positioning or surges.
+
+---
+
+## What limits a TT: sustainable power vs aerodynamic drag
+
+TT performance is a tug-of-war between the **power you can sustain** and the **power the air steals
+back**. Both matter, and the second is bigger than most riders assume.
+
+- **Aerodynamic drag is the dominant resistance at TT speeds.** At racing speeds the rider's body
+  is roughly **~80% of total system drag**, and overcoming air resistance consumes the large
+  majority of power output (Crouch et al. 2017, *Sports Eng* 20(2):81–110;
+  DOI 10.1007/s12283-017-0234-1). The classic validated power model that decomposes road cycling
+  power into aerodynamic, rolling, gravitational, bearing, and inertial terms — and shows aero
+  dominates on the flat — is Martin et al. 1998 (*J Appl Biomech* 14(3):276–291;
+  DOI 10.1123/jab.14.3.276; **no PMID — cite by DOI**).
+  - *(The often-quoted "~90% of power goes to aero at 40 km/h" figure traces to Kyle & Burke 1984,
+    a trade-magazine article not indexed in PubMed — treat the exact percentage as approximate;
+    the verifiable anchors are Crouch 2017 and Martin 1998. See `citations.md`.)*
+
+- **Reducing aerodynamic drag area (CdA) is the single largest performance lever.** Wind-tunnel-
+  guided position changes reduced professional cyclists' drag by **~14%**, with corresponding TT
+  time savings (García-López et al. 2008, *J Sports Sci* 26(3):277–286; PMID 17943597;
+  DOI 10.1080/02640410701501697). Position first, then equipment. A watt saved on the body is often
+  cheaper than a watt gained in the legs.
+
+## The physiological determinant: critical power / threshold
+
+A TT is run at or near the highest power sustainable for its duration, so the key predictor is
+**critical power / functional threshold**, not peak or anaerobic power.
+
+- Critical power correlated with 17-km and 40-km TT performance at **r = −0.77 to −0.91** — more
+  strongly than ventilatory threshold or VO2max (Smith, Dangelmaier & Hill 1999, *Int J Sports Med*
+  20(6):374–378; PMID 10496116; DOI 10.1055/s-2007-971147). *(Negative r: higher power = faster
+  time.)*
+- **Training implication:** the engine that matters is threshold/critical power and the fraction of
+  VO2max you can hold for the event duration. Build it with threshold and VO2max work
+  (`vo2max-intervals.md`) on a high aerobic base (`periodization.md`).
+
+## Pacing: even power on the flat, variable on terrain/wind
+
+- On a **flat, windless** course, **even / constant power is near-optimal** — resist the urge to
+  surge (Atkinson, Peacock & Passfield 2007, *J Sports Sci* 25(9):1001–1009; PMID 17497402;
+  DOI 10.1080/02640410600944709).
+- On **hilly or windy** courses, **vary power with the terrain**: push *above* target into climbs
+  and headwinds, ease *below* on descents and tailwinds. Because time is lost disproportionately
+  where you're slow, spending extra effort where it buys the most speed nets a faster overall time
+  than constant power (Swain 1997, *Med Sci Sports Exerc* 29(8):1104–1108; PMID 9268969;
+  DOI 10.1097/00005768-199708000-00017; refined by Atkinson et al. 2007 above).
+- **Prescribe pacing from power**, not feel — the whole point of a TT is holding a target the
+  cardiovascular system can't self-regulate under adrenaline.
+
+## Durability matters for long TTs
+
+For 40 km and up (and for TTs late in a stage race), **fatigue resistance** decides whether your
+threshold holds to the line. Durability is the resistance to deterioration of threshold/economy/
+power over prolonged exercise (Maunder et al. 2021, *Sports Med* 51(8):1619–1628; PMID 33886100;
+DOI 10.1007/s40279-021-01459-0). Train it via `durability.md`; for a long TT, your *fatigued*
+threshold is the one that counts.
+
+## HR in a TT: more usable than MTB, still secondary
+
+Unlike the intermittent efforts in `mtb-xco-demands.md`, a TT is steady-state, so HR tracks effort
+more faithfully and **aerobic decoupling is a valid durability signal** on a TT-pace effort. But:
+- HR still **lags the first minutes** (don't chase it off the start ramp) and **drifts upward**
+  from cardiac drift, heat, and dehydration over a long TT.
+- **Pace by power; use HR as a secondary check**, and screen the usual confounds
+  (`data-confounds.md`) before trusting a decoupling or drift number.
+
+## Practical checklist (pull data from MCP, reason here)
+
+- [ ] **CdA** addressed — position dialed before equipment (García-López 2008)
+- [ ] **Target power** set from current critical power / FTP for the event duration (Smith 1999)
+- [ ] **Pacing plan** matched to course: even on flat, terrain-variable on hills/wind (Swain 1997;
+      Atkinson 2007) — expressed in power, not HR
+- [ ] **Durability** trained if the TT is long or late in a stage race (`durability.md`)
+- [ ] **Warm-up** appropriate to duration (short TT = fuller prime; long TT = lighter)

references/vo2max-intervals.md

@@ -77,10 +77,13 @@ a solved problem.
     Rønnestad protocols (2016/2020/2021); good for riders who fade on long reps or want more total
     high-intensity work per session. Not proven superior once total work is matched.
   - **Long intervals (~4–5 min):** favored by the running time-at-VO2max data (Fleckenstein 2025)
-    and useful for **sustained** aerobic power and race-specific steady demands; a reasoned choice,
-    not a cycling-proven one.
-- **Prescribe from power.** For MTB especially, HR lags and misleads (`mtb-xco-demands.md`,
-  `data-confounds.md`).
+    and useful for **sustained** aerobic power and steady race demands like the TT
+    (`tt-demands.md`); a reasoned choice, not a cycling-proven one.
+- **Match reps to the event:** short/repeated efforts rehearse the surges of road racing
+  (`road-racing-demands.md`) and MTB (`mtb-xco-demands.md`); longer reps rehearse sustained TT power
+  (`tt-demands.md`).
+- **Prescribe from power.** For intermittent racing (MTB, road/crit) HR lags and misleads
+  (`mtb-xco-demands.md`, `road-racing-demands.md`, `data-confounds.md`).
 - **Verify the session worked:** pull the interval stats/streams from MCP and check power held near
   target across reps. Fading power = too much intensity or too little recovery; adjust work:rest.