What does the research on Hyrox actually say?

Followed for twelve weeks, 89 athletes trained a median of 7.0 hours a week in total, of which 3.0 hours was Hyrox specific. Recovery work, meaning prehab and stretching, was 12.5% of the hours they logged. And 62% of them had been doing this for under a year.

That last number is the one that should shape a coaching app. The median Hyrox athlete is not an experienced hybrid athlete managing a big training load. They are in their first year, training around an hour a day, and most of that is not Hyrox specific at all.

Three quarters of the athletes followed for twelve weeks reported at least one health problem, and 73% of the injuries were overuse rather than something that happened in one moment. The knee was the most common site at 22%.

The survey of 418 athletes, still a preprint, points the same way: half reported a Hyrox related injury in a year, the knee led at 20.8%, 41.6% were tendon related, and 57.4% came on gradually. Of the injuries anyone could attribute to a particular part of the race, running accounted for 27.6% and sandbag lunges for 11.8%, which is a lot for one station.

In that survey the only factor independently associated with reporting an injury was how many Hyrox specific sessions a week somebody did, at an adjusted odds ratio of 1.61. Weekly hours and self rated intensity both lost their association once the analysis adjusted for everything else. Age, sex and BMI showed nothing.

We are not turning that into a rule yet. It is a preprint, it is cross sectional, and the arrow could point the other way: people who train Hyrox often may simply have more to report. But it is the first evidence anyone has that the shape of the week matters more than its size, and it is exactly the kind of finding we would rather publish while it is still uncertain than quietly build on.

Until you have logged a station, the distance there is at most half the race distance, and wall balls at most half the 100 reps. The one exception is the test that gives you your first number there: the station once, at the race standard. Every session is built to the time you have. We do not claim that prevents anything.

What we will not do is claim we prevent injuries. The Bath authors call their own prevention suggestions untested hypotheses, and they collected the data. Nobody has shown that any Hyrox training approach lowers injury rates, ours included, and a coaching app that implies otherwise is selling something it does not have.

In the eleven athlete study, the strongest single predictor of finish time was VO2max, at ρ = −0.71 (p = 0.01), with endurance training volume close behind at −0.68 (p = 0.04). Grip strength came out at ρ = 0.09 (p = 0.79), which is nothing, and resistance training volume was not significant either.

The large dataset points the same way from a different angle: running is the discipline where finishing order stays most stable from season to season, while the loaded stations reshuffle the field far more.

One honest limit: nobody has actually measured maximal strength against Hyrox performance. The eleven athlete study tested hand grip, which is a convenient proxy and not the same thing. So "strength matters less than endurance" is the direction the evidence points, not a finding anyone has nailed down.

This is the one place every study agrees. In the measured race, heart rate, blood lactate and perceived effort all peaked at the wall balls, the final station, at 183 beats, 8.5 mmol per litre and 18 out of 20. In the elite dataset wall balls were the slowest station of the 2018 season at 5.98 minutes and the one that improved most as the sport professionalised, down 34.6% to 3.91 minutes. Sled push, by contrast, did not significantly improve at all in seven years.

Our training blocks are between three and six weeks: six for a beginner, five, four or three for more experienced athletes, and four when we do not know your experience. The phase counts back from your race date. That matches the mesocycle lengths the coaching literature describes, and there is no Hyrox specific evidence either way.

When your check in says you are very sore, today or the day before, the intensity the session is saved at is capped, whatever REX first set. What goes into it is still his call on the day.

That threshold is not settled science. The literature has no consensus cutoff and several sources argue against any single threshold, because sleep, mood and performance only mean something together. We use one anyway, because a coach has to decide something. If a better rule appears we will change ours and say that we did.

REX measures you inside your normal sessions, never in a test week: until every station has a measured number, your plan puts a test of one station still without one into one of your strength or hard sessions, one station a session, and never in the taper or race week. Once there are enough measured kilometres, he compares how much slower you run straight off a station than rested. We did not find this in any source. It comes from one principle we are not willing to give up: a coach who has not measured you is guessing.

A 1980 study put three groups through ten weeks: strength only, endurance only, and both at once. The combined group kept pace with the strength group for seven weeks, then levelled off and declined in weeks nine and ten, while its aerobic gains were untouched. That result is the origin of every "cardio kills your gains" article since, and for a sport that is half running it is the obvious thing to be worried about.

The current position is a 2021 review of 43 studies and 1090 participants. Training both at once did not measurably cost people either maximal strength (−0.06, not significant) or muscle size (−0.01, not significant). One quality did suffer: explosive strength, at −0.28 (p = 0.007).

Hyrox has no explosive station. Nothing in the race asks you to produce peak force in a fraction of a second. So the one interference effect that survives a thousand participants lands on the single quality this race does not test.

Even that explosive loss only showed up when the two kinds of work sat in the same session, within twenty minutes of each other. When at least three hours separated them, it was no longer significant.

We have not built around the three hour finding: one day holds one session. What we take from it is narrower. Explosive strength is the one quality that suffers, and this race does not test it.

The line you will read everywhere is that running interferes far more than cycling, because of the eccentric loading. In the 43 study review it is the other way around: cycling was the mode that showed an effect, and running showed none that reached significance. The cycling result did not survive the removal of one influential study either.

That is the same shape as the sixty percent story at the top of this page. One quotable line from an older and smaller analysis, repeated long past the point where better evidence arrived. We are not going to tell you to run less in order to protect strength you are not losing.