 |
| Photo by CNA/ Marcus Mark Ramos |
I also shared with her an article that was published last year that analyzed, in depth, the physiological responses and performance factors in Hyrox (Brandt et al, 2025).
Average heart rate during the event was 171 beats per minute. That's very high, easily above the 90 percent of maximum heart rate for probably everyone. In fact during 79 percent of the whole event, participants are competing at intensities of 90-100 percent of their maximum heart rate.
What set apart the better performers? VO2 max showed a strong relationship with finishing time. Spearman's rank coefficient was p = -0.71. It explains how critical an athlete's aerobic fitness is to their race success. Yes you read correctly, it's aerobic fitness, not strength. In exercise science, a correlation of 0.71 is considered strong. It proves that aerobic capacity (or fitness) is not just a minor factor, but a primary driver of performance.
In contrast, neither hand grip strength (a good predictor of work efficiency and fatigue management during sled pull, farmers carry and sandbag lunges) nor muscle mass percentage were good predictors. Hand grip strength also correlates with strength in other muscle groups and is used as a predictor for total muscle strength.
While variables like strength, pacing and transition speed matter, your raw capacity to absorb and utilize oxygen (VO2 max) is one the most reliable predictors of how fast you will finish the Hyrox event.
The negative sign indicates an inverse (or opposite) relationship, as an athlete's VO2 max increases, their race time decreases. This means they finish faster.
Recommendations for training?
According to the authors, endurance training should be emphasized at moderate intensities as well as forms of HIIT (high intensity interval training) to improve both aerobic and anaerobic capacity. Since 8 km of running is involved, a substantial amount of training volume needs to be dedicated to running based sessions.
Since excessive running mileage can increase injury risk, a strategy would be to replace or combine running with Hyrox specific endurance activities like rowing or skiing. Combining running with other Hyrox requirements should be an integral part of Hyrox training to improve running economy in a pre-fatigued state and will help with ability to transition between different metabolic demands.
Even though strength appears to be less important, participants still need to be able to move external weights as per competition standards. Previous research indicated that endurance and weight training may interfere with each other if done together, affecting adaptations. To minimise interference, separating strength and endurance into distinct sessions. If both are done together, the more important aspect should be trained earlier.
It is not enough to run fast in isolation. Not enough to just be strong either. You have to be able to keep running fast after you have rowed, pushed the sled, done wall balls and lunges etc. And to repeat it over and over again.
Your aerobic (or cardiovascular) engine, running and the ability to maintain performance while fatigued is crucial.
"More running?" My patient said. Definitely I said, at least more than what you have been running so far, since you have doing lots of strength training previously.
Reference
Brandt T, Ebel C, Lebahn C et al (2025). Acute Physiological Responses And Performance Determinants In Hyrox- A New Running-Focused High Intensity Functional Fitness Trend. Front Physiol. 16:1519240. DOI: 10.3389/fphys.2025.1519240
