Acute physiological responses and performance determinants in HYROX
The first scientific study on HYROX
Participants & Protocol
n=11 recreational HYROX athletes (27% women), median experience 18 months
Protocol
Observational study of a simulated competition, described as the first scientific study on Hyrox©: eleven recreational Hyrox© athletes (27% women) (from the abstract). Differences between runs and stations were analysed by Wilcoxon signed rank test; associations of completion times with participant characteristics by Spearman's rank correlation.
Pre-test: height, body composition, hand grip strength, VO2max, volume of resistance and endurance training
After 48 h rest, a simulated HYROX to "Individual Open Division" standards: 8 functional exercise stations alternating with runs; HR throughout, blood lactate and RPE at the start and after each run and station
Key Results (verified against published abstract)
Total time: 86.5 (14.5) min; running 51.2 min SIGNIFICANTLY longer than stations 32.8 min (p=0.003)
Most time at very-hard (79.5% of time) and hard (19.6%) intensity by %HRmax
Max lactate higher at stations (8.5 vs 7.7 mmol/L, p=0.006); max RPE higher at stations (18 vs 16, p=0.003)
Peak HR/lactate/RPE at the LAST exercise (wall balls)
Heaviest stations (sled push 128 s, sled pull 155 s) were completed FASTEST
Faster HYROX ↔ higher VO2max (p=0.01), greater endurance-training volume (p=0.04), lower body fat % (p=0.03)
Authors' conclusion: a HIFT modality with an emphasis on endurance capacity and moderate-to-low requirements in maximum strength, coordination and mobility compared with other HIFT forms
Practical Application
In 11 recreational HYROX athletes, a simulated race took 86.5 min of which 51.2 min was running vs 32.8 min at stations (p=0.003), 79.5% of the time at very-hard heart-rate intensity, and faster finishers had higher VO2max (p=0.01), more endurance-training volume (p=0.04) and lower body fat (p=0.03); the heaviest sled stations were the shortest. HYROX preparation priority is therefore the aerobic base, not maximal strength.
Strength stations: the study's lactate (8.5 vs 7.7 mmol/L) and RPE (18 vs 16) peaks came at stations and at wall balls last — inference, not tested: train station work as muscular endurance under lactate rather than maximal strength, and keep a reserve for the finish
Pacing: wall balls imposed the peak load; sled stations are short — Inference, not tested: do not overspend at the start
Lowering body fat % correlated with faster times — a lever, though cross-sectional
Limitations
n=11, recreational, single cohort, first-in-field — level B, not A
Individual Open Division only; Pro Division (heavier loads) may shift the balance toward strength
Cross-sectional correlations ≠ causation; no intervention
Elite HYROX athletes not studied — top-level determinants may differ
How this entry was checked and changed
Why this level
(n=11, first-in-field, single cohort)
Content correction 2026-09-27
Lead bullet "aerobic base + running economy" -> the study's own numbers and correlations (running economy was not measured); pacing and station-training advice labelled as inference.
"8×1 km running" -> "8 functional exercise stations alternating with runs" (run distance is not in the abstract); Tier "mixed→Tier 2" -> Tier 1-2 (recreational athletes, median 18 months' experience).
Cross-reference descriptions checked against the cited entries' current content; wrong years, wrong entries and claims the cited entry does not make were corrected.
2026-09-28: added a Protocol heading and design bullet from the abstract (Europe PMC PMID 40230601).