HYROX race plan: how to calculate splits

The first kilometer of HYROX is the cheapest one to run and the most expensive one to pay for. The athlete is fresh, the music is pumping, there are two hundred people around them setting off hard, and their watch shows a pace that would cost them blood in the gym. It feels amazing. Forty minutes later, at the sandbag lunges, they're negotiating with their own head just to avoid walking.

That athlete didn't lose the race from lack of strength or endurance. They lost it in the first six minutes, for not having a number to hold onto. And that number isn't something they can invent on race day: you have to give it to them, calculated, weeks in advance.

The race plan is probably the deliverable with the best effort-to-impact ratio you can add to your service. It takes an hour to put together, requires no infrastructure, and it's the first thing the athlete shows their gym buddies when they ask how they prepared.

Why HYROX pace can't be guessed

In a road race, the athlete has a clear reference: their best 10K time, their threshold pace, what they did last month. In HYROX that reference doesn't help, because the 8 kilometers aren't run fresh: they're run between eight stations that keep stacking fatigue, and each stretch starts with the heart rate already high.

On top of that, the order of the race isn't neutral. The first kilometers come after relatively gentle stations, and the last ones come after burpee broad jumps and sandbag lunges, which are precisely the ones that punish the lower body the most. An athlete can run kilometer 1 in 5:10 and kilometer 7 in 7:30 without having changed anything about their technique: the stations in between simply ran them over.

HYROX race pace isn't the pace your athlete can run. It's the pace they can run eight times, with one station ahead and another behind. These are two different numbers, and confusing them explains most of the races that fall apart in the second half.

That's why the plan isn't built on feelings or on the time the athlete wishes they could run. It's built on two tests, one subtraction, and four written rules.

Step 1: measure base pace and compromised pace

You need two numbers, and you can get them in two sessions, 72 hours apart, in any gym.

Test A: base pace

5 continuous kilometers at a controlled effort, the kind the athlete could sustain for an hour if they had to. It's not a max-effort test. What you're looking for is their honest aerobic pace, fresh, with nothing before or after.

Test B: compromised pace

Four 1-kilometer blocks, each preceded by a different station at race intensity. For example: SkiErg 1000 m + 1 km, sled push + 1 km, burpees + 1 km, sandbag lunges + 1 km. Time the four kilometers separately, not the total.

With those two numbers you have the only thing that matters: the compromise deficit, meaning how much slower your athlete runs when fatigued. It's calculated by dividing the average pace of test B by the pace of test A.

Small deficit (up to 15%): the athlete tolerates mixed work well. Their limiting factor is probably strength at the stations, not running.
Medium deficit (15% to 25%): the range most athletes fall into. The race plan is what's going to bring order to their second half.
Large deficit (more than 25%): you have an athlete who runs well and collapses under mixed load. Here the test's finding is worth more than any plan: you just found the training block for the next two months.

Pay attention to the detail almost nobody looks at: the difference between the first and fourth kilometer of test B. If they're similar, your athlete knows how to pace themselves. If the fourth is 40 seconds slower, you don't have a fitness problem, you have a pacing problem, and that's fixed with a piece of paper.

Athletes running inside the venue during an indoor fitness event — Photo by Mathieu Improvisato on Unsplash

Step 2: build the time budget

This is where the goal stops being a wish and becomes a calculation. A HYROX race splits into three buckets: the 8 kilometers of running, the 8 stations, and the roxzone. If you want a realistic goal, you have to fill all three.

Let's take a concrete case: an intermediate athlete aiming for 1:30:00.

Stations (estimated from their own training times): SkiErg 4:20, sled push 3:00, sled pull 4:00, burpee broad jump 5:00, rowing 4:30, farmers carry 2:00, sandbag lunges 5:00, wall balls 6:30. Total: 34:20.
Roxzone: 8 transitions at 40 seconds. Total: 5:20.
Running: what's left over. 90:00 minus 34:20 minus 5:20 leaves 50:20 for 8 kilometers, which is 6:18 per kilometer on average.

That 6:18 is the number that changes the race. If the compromised pace measured in test B was 6:10, the goal is achievable and you already know the margin is in the stations. If it was 6:50, the 1:30 goal is fantasy, and you have two honest options: run the next race with a different goal, or put in eight weeks of specific work before promising anything.

This conversation, held with numbers on the table two months before the race, is one of the most valuable ones you'll have with a client. You're giving them something no watch can: a calibrated expectation. And at the same time, you're covering yourself for the day the result isn't what they expected.

Step 3: distribute the splits (and hold them back at kilometer 1)

An average of 6:18 doesn't mean running all eight kilometers at 6:18. It means distributing them so the eighth one is actually possible. The practical rule that works best:

Kilometers 1 and 2: 10 to 15 seconds slower than the target average. Yes, slower. It's the hardest instruction to enforce and the one that saves the most races.
Kilometers 3 to 5: right at the target average. This is the cruising zone, where the athlete has already settled in and the accumulated fatigue from the hard stations hasn't shown up yet.
Kilometers 6 to 8: allowed to lose 10 to 20 seconds per kilometer. It's not a failure, it's budgeted. Knowing in advance that it's going to get slow prevents panic and keeps the athlete from trying to compensate by chasing time that isn't there.

Also write down the time cap for each station, not just the running pace. The combination of the two is what gives them judgment in the moment: if they come off the row 30 seconds over the plan, they need to know that doesn't get fixed by running the next kilometer faster, because the cost of that rush gets paid back with interest at the wall balls.

Coach reviewing a printed table of times and paces per kilometer for a race

Step 4: in-race decision rules

A splits plan without decision rules gets abandoned at station 3. What holds the plan together under stress isn't the numbers, it's three or four binary instructions the athlete can remember with their heart rate at 180. These are the ones that work best:

The kilometer 1 rule: if the watch shows faster than the assigned pace, ease off. No exceptions, no matter how good it feels. How kilometer 1 feels is a statistical lie.
The no-rescue rule: time lost at a station doesn't get recovered by running. You accept it and stick to the original plan.
The fixed-partitioning rule: the sets for the long stations are defined before the race, not based on how it feels. Wall balls and burpees get broken up from the start, even if at first it seems unnecessary.
The decision-point rule: a single moment in the whole race, right after the row, where the athlete is allowed to review the plan and decide whether to push or to manage. Just one, and always at that fixed spot.

Four rules, not ten. The restriction is part of the design: under extreme fatigue, decision-making capacity drops off a cliff and the only thing that survives is what was rehearsed.

Step 5: rehearse it before the race

A plan the athlete reads for the first time on Friday night isn't a plan, it's a printed wish. Build it into the cycle:

Partial simulation at target pace: 4 stations with their kilometers, running exactly at the assigned splits. The goal isn't the total time, it's for the athlete to learn to recognize that pace in their body.
Restraint session: a set where you deliberately ask them to run the first kilometer slower than they want to. It sounds silly and it's the session that pays off the most.
Partitioning rehearsal: the wall balls and burpees with the exact scheme they'll use on race day, including the pauses and their length.

Adjust the plan after each rehearsal. The numbers on paper aren't sacred: the first version is always optimistic somewhere, and finding that out in the gym is much cheaper than finding it out at kilometer 6.

How this turns into a sales argument

The HYROX coaching market is already pretty crowded, and the offerings look too much alike: weekly programming, some WhatsApp follow-up, and good vibes. The race plan sets you apart for three concrete reasons.

It's a tangible object. The athlete is paying for a service that's generally invisible: messages, spreadsheets, corrections. A single page with their name, their goal, and their paces is something they can touch, keep, and show off. The perceived value of your work jumps just from that.
It's impossible to copy without data. Anyone can copy a program off Instagram. Nobody can copy your athlete's splits, because they come from their tests, their deficit, and their station times. It's the cleanest proof that your service is personalized and not a template with their name slapped on top.
It turns the result into a measurable conversation. After the race you compare plan against execution, kilometer by kilometer. Whatever the outcome, you have material for the debrief and for selling the next block with a clear focus.

And there's a benefit that shows up on no spreadsheet: the athlete reaches the starting line with less anxiety. They don't have to decide anything, it's already decided. And they're going to associate that with you.

So this doesn't depend on your memory or a note on your phone, you need the data somewhere. In ATHRIX you can log the tests as workouts with their blocks, save the station times from each simulation, and build the race plan on the athlete's real history instead of an estimate. Once the race is done, you log the actual splits, put them next to the planned ones, and the next version of the plan writes itself. By an athlete's third race, you have something almost no coach has: a historical record that shows exactly where they improved and where they didn't.

Conclusion

Most HYROX athletes run their race twice: the first half hour at a pace they can't sustain, and the next hour paying that bill. It's not a fitness problem, it's an information problem.

Measure base pace and compromised pace, build the time budget across running, stations, and roxzone, distribute the splits with the first two kilometers deliberately slow, write four decision rules, and rehearse all of it beforehand. It's an hour of your work per athlete. In exchange, your clients lower their times, understand why they lowered them, and have something concrete to show when someone asks who they train with.