HYROX and the half IRONMAN: what two studies of amateur athletes say
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HYROX: a study of 11 amateur athletes
The first scientific study of HYROX followed 11 amateur athletes (27% women, median experience 18 months) in a simulated race in the Individual Open division. Median time was 86.5 minutes: 51.2 running and 32.8 on stations. Most of the race was done at high heart-rate intensities. Lactate and perceived effort were higher on the stations than in the runs, with the highest values at the last station (wall balls). The heaviest stations were the fastest: sled push 128 seconds and sled pull 155 seconds (median values).1
Faster athletes had higher VO2max (rho = -0.71), more endurance training volume (-0.68) and lower body fat (0.67). Analysing runs and stations separately, the associations appeared only for the runs.1 The authors conclude that HYROX is a modality with an emphasis on endurance capacity and moderate to low requirements for maximal strength, coordination and mobility compared with other forms of high-intensity functional training.1
Limits: the sample is small, almost all participants had good to excellent cardiorespiratory fitness, the race was simulated, and correlations do not show that changing one characteristic changes race time.1
Half IRONMAN: a study of 18 amateur triathletes
Eighteen male amateur triathletes with less than two years of triathlon training followed the same supervised programme toward a half IRONMAN. They were split into two groups by how their training time was spread across three zones: polarized (84.5% / 4.2% / 11.3% in zones 1, 2 and 3) and pyramidal (77.9% / 18.8% / 3.3%). Zones were based on ventilatory thresholds measured in running and cycling and on an 800 m test for swimming.2
Time in zone 2 was inversely correlated with swim and bike times in the polarized group and with run and total times in the pyramidal group: more zone 2 time, better times. The authors infer that coaches should not rule out zone 2 and state that experimental studies are needed.2 Stated limits: short specific training period, small sample, and other factors affecting a long race (weather, nutrition, hydration) not accounted for.2
How to read them
Both are observational studies of few athletes: they say what was associated with results in that group, not what to do to improve. We do not turn the results into zones, volumes or sessions. For swimming see Training methods; for HYROX and IRONMAN formats and rules see Races and formats.
What we know and what we do not
We know what was observed in two small groups of amateurs. We do not know how to prepare effectively for a HYROX or a long triathlon for a specific person: we have not read experimental studies on this.
How we reviewed it
Document review of two observational studies of amateur athletes (11 and 18 participants).
Limits. Small samples, non-causal associations; simulated HYROX and very fit athletes; half IRONMAN with males under 2 years of triathlon only; no applicable plan.
Sources
- Brandt, Ebel, Lebahn, Schmidt. Acute physiological responses and performance determinants in Hyrox© - a new running-focused high intensity functional fitness trend. Frontiers in Physiology, 2025. doi.org/10.3389/fphys.2025.1519240 (text read)
- Selles-Perez, Fernández-Sáez, Cejuela. Polarized and Pyramidal Training Intensity Distribution: Relationship with a Half-Ironman Distance Triathlon Competition. Journal of Sports Science and Medicine, 2019. PubMed Central (text read).
Sources rechecked on 28 October 2026. Wolf Lab is not affiliated with HYROX or IRONMAN.