Private alpha · By invitation
Know how your race will actually go.
Race execution is more than a prediction and a goal pace.
A pace calculator hands you a single number. Endurance-IQ models your physiology against your real race — course, weather, fuel — and gives you a goal range, the conditions that move it, the failure modes that could end your race early, and exactly how confident to be in each.
Built with a coach and an exercise physiologist · Invite-only proof of concept
BIG SUR MARATHON
Your race card · goal range
A pace calculator says
3:23:03
One number. Take it or leave it.
Endurance-IQ says
3:35:17–3:37:51
Course profile · Big Sur International Marathon · +1752 ft
Segmented pacing · example values
Fueling · per hour · plan inputs
68g
Carbs
0.50L
Fluid
700mg
Sodium
In early validation, EIQ's training-derived threshold estimate matched an athlete's race-proven fitness within seconds per mile — where a leading watch platform ran about 10 sec/mi optimistic on the same athlete.
Single-athlete validation · alpha calibration cohort in progress
Simulate before you commit
See mile 23 before you run mile 1.
Ten physiology models run in coupled simulation — heat, hydration, fueling, glycogen, durability — so a decision at the start shows its cost at the finish.
- Drag the opening pace and see exactly what it costs — or saves — at the finish.
- Stress-test the forecast. Slide humidity up 10% and see the window move before race morning does it for you.
- Failure modes, not vibes. Hydration risk called at the plan; fueling gauges unlock as the model learns your gut.
WHAT-IF SIMULATOR
Five levers · watch race day move
Most-likely finish window
3:35:17 – 3:37:51
On planMile 23
holds 8:40
Hydration
deficit risk — drink more
Glycogen
unlocks with your runs
GI risk
unlocks with gut training
Glycogen & GI gauges stay locked until the model earns your calibration — it won't pretend.
Fueling & hydration
A fuel plan your gut can actually absorb.
Carbohydrate absorption, fluid, and sodium are modeled together — because 85g/hr on paper means nothing if your gut taps out at mile 18.
- Real products, not abstractions. The plan is built from your gels — Maurten, SiS, GU, Precision — with verified macros per serving.
- GI load tracked through the race, so the plan backs off before distress ends your day.
- Weigh 85g vs 65g per hour and see exactly where the trade-off starts to bite.
FUELING PLAN
Big Sur · 3:35:17 – 3:37:51 · 61°F, 78% RH
Projected GI load — unlocks with calibration
A model that learns you
Calibrated every run, not annually.
Every .FIT file you upload sharpens the model — heat sensitivity, sodium loss, GI tolerance, durability under load, pace anchors at real efforts.
- Ranges narrow as evidence grows. A 20-miler with the last 8 at marathon pace teaches us more than any fitness chart.
- Every number carries its provenance. You always know what's measured, what's derived, and what's still a default.
- When we don't know, we say so — and the range widens honestly instead of pretending.
YOUR THRESHOLD ESTIMATE
Narrowing with every calibration run
Lock it & race
The whole plan, on the start line.
Refine the analysis, then lock a phone-friendly race card — splits, fuel timing, and the two or three alerts that actually matter mid-race.
- Segment paces for the course you're running, not a flat-earth average.
- Fuel alerts pinned to the miles where the model says they're needed.
- Debrief after, and the model gets sharper for your next race.
Race card · Locked
BIG SUR
3:35:17 – 3:37:51What we do differently
Ranges, not single numbers.
Most tools optimize one variable and call it a plan. We model the whole system — and we tell you where the evidence is thin.
Heat, hydration, fueling, durability — together
Ten physiology models run in coupled simulation. Heat strain affects sodium loss, which affects GI tolerance, which affects fueling, which affects glycogen reserves. We don't isolate one signal and call it a plan.
Calibrated every run, not annually
Every run you upload shapes the model. A 20-mile run with the last 8 at marathon pace teaches us more about you than a generic fitness chart ever could.
Every number shows how much evidence is behind it
When we don't know something, we say so. When evidence is thin, the ranges widen. When you give us calibration runs, they narrow. You always know what's proven and what still needs proof.
From profile to start line
Five steps. Sharper every race.
Tell us about you
Basics, recent PRs, your goal race and fueling approach.
Connect training
Upload .FIT files after runs so the model learns what's specific to you.
Build the analysis
Your model, run against your race. A goal range, explained.
Refine & lock
Tune the plan, then lock a phone-friendly race card.
Debrief & learn
Capture race day. The model gets sharper for the next one.
Private alpha
Race day is one shot. Walk in knowing.
Endurance-IQ is invite-only while we calibrate with our first runners. Request access and we'll be in touch.