01 · Track
Start with observable facts
Distance, altitude, elevation and geometry come from the file. Technicality, weather and trail condition still need confirmation.
Race plan masterclass
Turn a GPX into a race plan you can actually use
An elevation profile does not predict your day. It provides the structure for sustainable effort, honest time windows, realistic self-sufficiency and prepared decisions.
Scientific revision 1.0 · 31 July 2026The GPX describes the course→Your history calibrates the estimate→The plan prepares decisions
Demonstration
One GPX, five successive readings
This fictional simulation teaches a method. Its times must not be reused for another race.
Teaching example · 74 km · fictional data
Core principle
Separate what you know, what you estimate and what you will decide
A useful plan stays readable when weather changes or a split takes twenty minutes longer. Every value needs a clear status.
Fact
GPX distance, track altitude, official aid-station location or cut-off.
Even facts may be incomplete: noisy GPS, route changes or relocated support.Estimate
Segment duration, passage time or carrying need computed from explicit assumptions.
An estimate is not a promise; confidence falls as context goes missing.Decision
Effort intent, planned stop, carrying strategy or action triggered by a deviation.
A rigid decision becomes unsafe when it ignores terrain, symptoms or race instructions.Useful precision is not decimal places. It is the ability to explain where a value came from, what can move it and which decision it supports.
Step 1
Segment the course when the decision changes
Equal kilometre splits create noise. A segment starts when effort, risk, self-sufficiency or logistics change.
Start or end of a sustained climb, summit transition or long descent.
Moving from runnable to technical, mud, snow, rocks or narrow trail.
Altitude, wind, sun, cold, no-exit zone or likely night section.
Confirmed water, official aid station, life base or authorised crew access.
Cut-off, mandatory gear, closure or special race rule.
Where you must check effort, refill, layer up or reassess the plan.
×Poor segmentation: equal distances mixing climb, summit and descent.
✓Good segmentation: each unit can receive one effort intent, probable duration and simple instruction.
Step 2
Plan effort expenditure, never uniform speed
Locomotion cost changes sharply with grade. Pace per kilometre is a terrain outcome, not a universal command.
ContextIntentSimple checkFrequent error
Runnable startDeliberate restraintEasy breathing; feeding starts comfortably.Mistaking start-line excitement for a sustainable feeling.
Long climbStable effort, early hikingRegular steps, controlled breath, no need to chase.Running to save minutes and paying the debt downhill.
DescentProtected flowClean foot placement, limited braking, full clarity.Chasing an early gain through premature muscle damage.
Late raceAdapt from today’s evidenceDecide from legs, alertness and remaining supplies.Obeying a pace written weeks earlier at all costs.
Observational studies often associate steadier pacing with better results, but “steady” here means controlled expenditure, not identical speed on every gradient.
Step 3
Build honest passage windows
One time looks reassuring but hides uncertainty. Use three scenarios and widen the window as the race progresses.
Dry trail, mild weather, smooth stops. Not a target to chase.
Most likely assumptions, calibrated on comparable efforts.
Fatigue, heat, technicality or longer stops. Adapt to actual uncertainty.
Calibrate
Use comparable races or outings, not your best road pace.
Add
Movement time and stopped time are separate visible costs.
Widen
Later, longer, night or exposed segments need wider uncertainty.
Compare
Compare cut-offs with the cautious scenario, not only the central one.
Example passage sheet
MarkerDistanceContextCentralWindowConfidence
Pass A14 kmSteady climb2 h 102 h 00–2 h 25Medium
Aid B29 kmTechnical descent4 h 053 h 45–4 h 35Medium
Summit C47 kmLong climb7 h 206 h 45–8 h 15Low
Base D61 kmLikely night9 h 559 h 05–11 h 20Low
These percentages and times illustrate a method. They are not universal Trailboard engine parameters or a prediction for your race.
Step 4
Size self-sufficiency between reliable resources
An aid station reduces carrying only when its location and supplies are confirmed. A map icon or last year’s memory is not enough.
Reproducible reasoningCarry = segment need + chosen margin − confirmed resource
Segment need combines estimated duration and hourly target. Margin follows uncertainty, heat and actual resupply options.
Carbohydrates
What target was tolerated at a comparable duration and intensity?
Compute segment total and distribute intake without long gaps.Fluids
What intake was observed in similar conditions?
Plan carrying capacity without forcing drinking beyond need or thirst.Sodium
What is known about sweat rate and concentration?
Keep the assumption visible and never treat sodium as insurance against all hyponatraemia.Backup
What if water is unavailable or one food becomes intolerable?
Carry a simple, tested alternative compatible with the pack.Carried quantity must be explainable per segment. Unknown needs remain ranges and unconfirmed resources remain outside the calculation.
Step 5
Write decisions before fatigue makes them harder
A robust plan cannot predict everything. It prepares simple responses to common deviations and defines when safety replaces performance.
Trigger
→Passage leaves the central window but still clears the cut-off.
First action
→Identify the cause: terrain, stop, effort or physical issue.
Adjustment
Recalculate from actual time without punitive acceleration.
AvoidTrying to win twenty minutes back on the next climb.
Confusion, collapse, chest pain, persistent vomiting, inability to drink or pain changing gait are not plan deviations to optimise: stop and seek assistance.
Final deliverable
Your roadbook should make sense in thirty seconds
On race day nobody rereads the model. The final sheet must expose facts, windows, supply and decisions without ambiguity.
Course
- Named markers
- Segment distance and elevation
- Notable terrain or exposure
- Official cut-offs
Time
- Central arrival
- Favourable-cautious window
- Stopped time separated
- Confidence level
Supply
- Confirmed resources
- Quantity to carry
- Segment gear
- Tested backup
Decision
- Effort intent
- Simple check
- Plan-B trigger
- Stop signal
When data is not confirmed, write “unknown” or “assumption”. An empty cell must never look like absence of risk.
Bibliography
Evidence supporting the method
Pacing studies are mostly observational. They describe associations and trends; they do not prescribe an individual pace.
- de Waal et al. (2021)Scientific reviewPhysiological Indicators of Trail Running Performance: A Systematic Review. Int J Sports Physiol Perform. doi:10.1123/ijspp.2020-0812.
Shows why distance, grade, terrain, physiology and technique must be considered together.
↗ - Minetti et al. (2002)Experimental studyEnergy Cost of Walking and Running at Extreme Uphill and Downhill Slopes. J Appl Physiol. doi:10.1152/japplphysiol.01177.2001.
Measures the nonlinear change in energy cost with grade; one kilometre never has a constant cost.
↗ - Kerhervé et al. (2016)Observational studyPacing During an Ultramarathon Running Event in Hilly Terrain. PeerJ. doi:10.7717/peerj.2591.
Describes speed loss by gradient category and trail-specific pacing variability.
↗ - Nikolaidis et al. (2020)Observational studyEven Pacing Is Associated with Faster Finishing Times in Ultramarathon Distance Trail Running: The UTMB 2008–2019. Int J Environ Res Public Health. doi:10.3390/ijerph17197074.
Associates steadier pacing with faster results across several UTMB editions.
↗ - Genitrini et al. (2022)Observational studyDownhill Sections Are Crucial for Performance in Trail Running Ultramarathons: A Pacing Strategy Analysis. J Funct Morphol Kinesiol. doi:10.3390/jfmk7040103.
Highlights the importance of preserving downhill speed in later race stages.
↗ - Costa et al. / World Athletics (2019)Scientific reviewNutrition for Ultramarathon Running: Trail, Track, and Road. Int J Sport Nutr Exerc Metab. doi:10.1123/ijsnem.2018-0255.
Connects nutrition, aid-station logistics and ultramarathon-specific demands.
↗ - Tiller et al. / ISSN (2019)Position standISSN Position Stand: Nutritional Considerations for Single-stage Ultra-marathon Training and Racing. J Int Soc Sports Nutr. doi:10.1186/s12970-019-0312-9.
Frames race intake, individual tolerance and gut training.
↗ - Hew-Butler et al. (2015)ConsensusStatement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference. Clin J Sport Med. doi:10.1097/JSM.0000000000000221.
Safety consensus on excessive fluid intake and exercise-associated hyponatraemia.
↗ - Racinais et al. (2015)ConsensusConsensus Recommendations on Training and Competing in the Heat. Br J Sports Med. doi:10.1136/bjsports-2015-094915.
Frames how heat changes sustainable intensity, cooling and hydration.
↗ - Kishi et al. (2024)Observational studySleep and Ultramarathon: Patterns, Strategies, and Repercussions of 1,154 Mountain Ultramarathon Finishers. Sports Med Open. doi:10.1186/s40798-024-00704-w.
Documents sleep management, alertness and reported consequences in mountain ultras.
↗