Private alpha · By invitation
Know how your race will actually go.
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
A pace calculator says
3:35:00
One number. Take it or leave it.
Endurance-IQ says
3:33:08–3:37:38
Most-likely finish window · Big Sur Marathon
Confidence: building · open 8:17–8:37/mi
The question
What if you could see it before race day?
Most marathoners train for months — then pick a goal pace from intuition, a Garmin or Strava predictor, or an outright guess. Endurance-IQ lets you ask sharper questions:
What if you could simulate your current fitness on the actual course, with its actual weather, running your fueling and hydration plan?
What if you could see what happens at mile 23 when you open the first 10K at 7:25 — versus 7:45?
What if you could model the race with humidity 10% higher — or lower — than you're expecting?
What if you could weigh 85g of carbs an hour against 65g — and see where it starts to bite?
Find out with Endurance-IQ. Request an invite ›
What 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.
Who it's for
Built for two kinds of runners.
Different goals, same problem: one race day, no do-overs, and too much riding on getting the execution right.
Chasing a Boston qualifier or a hard-won PR
Faster age-groupers who want a data-driven, risk-aware plan — and refuse to leave time on the course or blow the race with a reckless opening 10K.
Protecting one big investment
Newer marathoners who've put real money, real training, and real months into a single goal race — and want to protect that investment from a mile-20 collapse.
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.
Where this comes from
Grounded in coaching practice and exercise physiology.
Endurance-IQ is built from two decades of endurance racing, coaching practice, and a physiology-first approach to race execution. The models reflect what works with real athletes — published research, measured signals, and the things that go wrong on race day when assumptions don't hold.
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.