What the research says
about HYROX training

Brandt and colleagues studied 11 recreational athletes, including three women, in an Individual Open simulation. Higher VO₂max correlated with a shorter finish time (Spearman’s ρ = −0.71). This was an association in a small sample, not a universal prediction formula.

The study did not test whether losing body fat or adding more endurance hours causes a faster race. Grip strength was measured; this cannot establish that all forms of strength are unimportant.

In the same 11-person study, median total time was 86.5 minutes, with 51.2 minutes running and 32.8 minutes at stations. These are group medians, not a fixed breakdown for every athlete.

The simulation used treadmill running, a different sled and no competitors or spectators. A race-time share does not prescribe the same percentage of your training week.

Duffuler analysed more than 14,000 Male Open performances from 15 events in 2024–2025. Wall balls, sandbag lunges and burpee broad jumps showed substantial variation between athletes and strong associations with total time.

This published data analysis is not a controlled training trial or evidence that these are the three best priorities for every woman, Pro athlete or Doubles team.

In that Male Open dataset, runs 5–8 had correlations with total time reaching 0.79. The analysis describes how performances varied; it did not test whether a particular pacing intervention improves results.

A split is also part of the total being compared. Correlation alone cannot identify the cause of a slower race or prove that one segment decides the outcome.

Brandt’s simulation recorded high heart rates and perceived effort. Its full paper reports different intensity percentages from the SSAC summary. We therefore do not repeat the report’s “70.5%” as a universal race statistic.

A percentage of maximum heart rate is not an individually measured lactate or ventilatory threshold. The study did not establish that athletes should perform long threshold efforts in every training week.

The cited scoping review maps 39 studies on HIFT, CrossFit and related concurrent training. It combines different designs and populations; it is not 39 trials of one HYROX programme.

The review describes aerobic and strength improvements, but its reported percentage ranges are not pooled guarantees for HYROX athletes. It also discusses small samples and heterogeneous methods. “No trade-off” is stronger than this evidence supports.

The report places an “83% after six weeks” neuromuscular-adaptation claim alongside the Brandt study. That paper examined acute responses to a simulation, not a six-week training intervention. It cannot substantiate that claim.

We have removed the promised adaptation rate and deadline. Neither this study nor the report demonstrates that REPZ users will achieve a particular result.