HYROX IS NOT NEW SCIENCE

Hyrox has exploded. 175,000 competitors worldwide in 2023. 5,000 affiliated gyms by the end of 2024. It has got a huge number of people training with purpose, which is brilliant. The standardised format means you can compare performances globally, and the community around it is massive. I have watched it grow from a niche event to something that fills exhibition centres.

Having spent years in endurance sport and now coaching athletes across cycling, triathlon and running, I find Hyrox interesting because the physiological demands are not new. The format is new. The equipment is new. But what your body actually needs to do to get through a Hyrox is the same stuff endurance athletes have been training for decades. That is not a criticism. It is just an observation that might help people think about their training differently.

WHAT THE RACE ACTUALLY IS

Strip away the branding and look at what a Hyrox race asks you to do. You run 8 kilometres total, broken into 8 x 1km efforts. Between each run you complete a functional station: ski erg, sled push, sled pull, burpee broad jumps, rowing, farmers carry, lunges, and wall balls. Elite men are finishing in around 53 to 56 minutes. Elite women in around 56 to 63 minutes. The average finisher in the Pro division takes around 1 hour 20 to 1 hour 30. Across all divisions, the average is closer to 1 hour 35 to 1 hour 50.

That is a 60 to 90 minute effort combining sustained running with repeated bouts of functional work. Running makes up over half the total race time at every level. The stations require a baseline of strength, muscular endurance, and the ability to maintain output while fatigued. None of the movements are technically complex. There are no gymnastics skills. No Olympic lifts. No high-skill barriers. You need to be strong enough to handle the loads, fit enough to sustain the effort, and skilled enough not to waste energy.

The question I find interesting is where the biggest limiters are for most people. And from what I have seen, both racing and coaching, the aerobic system tends to be the bottleneck more often than strength.

Look at the best Hyrox athletes in the world. Their running is at a very high level. The elite women have 5k times around 16 to 17 minutes. The elite men are similar or faster. During a Hyrox race, these athletes are averaging around 4:30 to 4:50 per kilometre across the full 8km, even with all the station work in between. That is serious running fitness maintained under fatigue. You do not get to that level of Hyrox performance without a very well developed aerobic engine.

This does not mean strength is irrelevant. You absolutely need to be strong enough to push a heavy sled, carry kettlebells for 200 metres, and do 100 wall balls at pace. If you cannot physically handle the loads, you will struggle. But once you have a reasonable base of strength, the thing that separates faster times from slower times tends to be aerobic capacity and the ability to recover between stations.

WHY THE AEROBIC SYSTEM MATTERS SO MUCH

A 60 to 90 minute effort draws heavily on the aerobic system. The exact contribution depends on intensity, but for most Hyrox finishers, the aerobic system is doing the bulk of the work. The stations spike your heart rate and create local muscular fatigue, but the reason you can keep going is because the aerobic system is clearing lactate, replenishing energy stores, and allowing you to recover between efforts.

The sled push is a good example. It lasts maybe 30 to 60 seconds for most people. Your legs burn, your heart rate spikes, and it feels very anaerobic in the moment. But the load itself is not the problem. Most people can physically push the sled. The problem is recovering from it quickly enough to run the next kilometre at pace. That recovery is aerobic. The bigger your aerobic engine, the faster you clear the metabolic byproducts and get back to baseline.

This is why I think running fitness is such a good predictor of Hyrox performance. It is not that the sled or the wall balls do not matter. They do. But if your aerobic system is well developed, you recover faster between stations, you can sustain a higher pace on the runs, and you do not fade as badly in the second half of the race. If your aerobic system is underdeveloped, every station digs a hole that you cannot climb out of.

The wall balls at the end of the race feel brutal not because 100 reps is inherently difficult for a reasonably fit person. They feel brutal because you have been working for over an hour and your body's ability to deliver oxygen, clear waste products, and maintain output has been gradually degraded. That is cumulative fatigue. The same thing happens to a cyclist on the final climb of a stage race or a runner in the last 5km of a marathon. The task itself is not beyond you. Your capacity to sustain the effort is what has been eroded.

A triathlete coming off the bike and having to run a 10k on fatigued legs is doing the exact same thing as a Hyrox athlete running their fifth 1km after sled push, sled pull, burpee broad jumps and a 1km row. The muscles are tired, the heart rate is elevated, and you have to find a way to maintain pace. This is not a Hyrox specific adaptation. This is a well-understood physiological challenge that endurance coaches have been dealing with for decades.

Think about what triathlon training looks like. You swim, bike and run. You do brick sessions where you run off the bike. You build aerobic capacity across three disciplines. You practice transitions. Now think about what good Hyrox training should look like. You run. You do station work. You do sessions where you run between stations. You build aerobic capacity across running and functional movements. You practice transitions. It is the same structure. The swim has been replaced by a ski erg. The bike has been replaced by sleds and wall balls. The underlying training approach is identical because the physiological demands are identical.

THE NUMBERS DO NOT LIE

A 90 minute effort is overwhelmingly aerobic. Somewhere around 85 to 90% of the total energy production comes from the aerobic system. But even that number undersells it because even the stations that feel anaerobic are still being serviced by the aerobic system. The anaerobic glycolytic system contributes during the harder stations, sure. But the reason you can do the next station and the next run is because the aerobic system is clearing the mess, replenishing phosphocreatine stores and bringing your heart rate back down. Without a big aerobic base, you never recover. Every station digs a deeper hole that you cannot climb out of.

Look at that chart. A Hyrox race sits in virtually the same energy system window as a half marathon, an Olympic distance triathlon, or a road cycling race. The aerobic system is doing the vast majority of the work in all of them. The stations do not change this. They just add variety to how the aerobic demand is delivered. Your body does not care whether it is delivering oxygen to your quads while you run or while you push a sled. The cardiovascular system, the mitochondria, the lactate shuttle all work the same way. The training to improve them is the same too. VO2max, lactate threshold, running economy, cardiac output. These are the same variables that endurance coaches have been optimising for decades. Hyrox has not changed the physiology. It has just put it in a different wrapper.

SO WHAT IS ACTUALLY NEW

Two things. The format and the specificity.

The format is genuinely clever. Eight standardised stations with a consistent global race means everyone can compare performances. That creates competition, community and repeat participation. It is a brilliant business model and a great event. From a participation and motivation standpoint, Hyrox has done something that most endurance sports struggle with. It has made training for a race accessible and fun for people who would never enter a marathon or a triathlon.

The specificity is where the training application sits. If you want to get good at Hyrox, you need to practice the specific movements. You need to know your way around a ski erg. You need to have done sled push at race weight so you know how to pace it. You need to have done wall balls under fatigue so you know your set and rest strategy. You need to practice running on tired legs after heavy station work.

That is skill practice and sport specific preparation. It is not a new training methodology. It is the same principle that applies to every sport. A triathlete practices transitions. A cyclist practices cornering under fatigue. A Hyrox athlete practices sled push after a 1km run. The concept is identical.

WHAT I SEE PEOPLE GETTING WRONG

From my experience coaching endurance athletes who have crossed over into Hyrox, and from talking to people who come from a gym background, there are a few patterns I notice.

The first is underestimating how important the running is. Running makes up over half the race time. If your running is weak, you are giving away huge amounts of time that you cannot make back on the stations. A lot of people focus heavily on the stations because that is the novel part, the interesting part, the part that feels like Hyrox specific training. But the biggest time savings for most people are in the 8km of running, not the stations.

The second is thinking of the stations as "the strength part" and the running as "the cardio part." It is more useful to think of the whole thing as an aerobic event where some of the aerobic demand is expressed through functional movements. The sled push is not a strength test in the way a powerlifting meet is. It is a sustained effort that happens to require leg strength. The energy system driving it is still predominantly aerobic.

The third is not training specifically for the stations. You do need to practice the movements. You need to know how a sled feels at race weight. You need to understand your pacing strategy for the ski erg and the row. You need to have done wall balls under fatigue so you know when to break and when to push through. Specificity matters. You cannot just be generally fit and expect to perform well without practicing the actual demands of the event.

THE BOTTOM LINE

Hyrox is a great event. It has got hundreds of thousands of people training with structure and purpose. The format is clever, the competition is addictive, and the community is brilliant. I think it is one of the best things to happen to fitness in years because it gives people a clear goal to train for.

From an exercise physiology perspective, what Hyrox demands is not new. It is a 60 to 90 minute effort that requires aerobic fitness, strength, muscular endurance, and the ability to perform under fatigue. Endurance athletes have been training these qualities for decades. The tools are different, the format is different, but the underlying physiology is the same.

If you are coming from an endurance background, you probably already have a strong aerobic base. Focus on building enough strength for the stations and practicing the specific movements. If you are coming from a gym background, you probably already have the strength. Focus on building your running and your ability to sustain effort over an extended period.

Either way, be honest about your limiters. For most people I have worked with, improving their aerobic fitness has a bigger impact on their Hyrox time than adding more strength work. That is not always the case, but it is the pattern I see most often. The fitter you are aerobically, the faster you recover between stations, and the less you fade in the second half of the race. That is where the time is.