REF-904 · Chittenden et al., 2026 · Frontiers in Sports and Active Living, Vol. 8, Art. · Paper · PubMed · Free full text

Prevalence, burden and risk markers of health problems in HYROX athletes: a 12-week prospective cohort study

Blimited evidenceMeasured on recreational to highly trained athletesWritten before October 2026, being re-checked

Eighty-nine HYROX athletes (56 women) completed the OSTRC-H2 health-problem questionnaire weekly for 12 weeks with exposure logs and a baseline questionnaire. In an average week 30% reported some health problem and 18% a substantial one. Injury incidence was 14.4 per 1,000 h, about two thirds of it attributed to HYROX training, and 73% of injuries were overuse.

The knee was the most often injured region and, with the lower leg, carried the most burden — in line with the running load — while the elbow ranked third on only four episodes and shoulder injuries were near-absent. Only half of problems caused time loss. Previous injury carried the largest rate ratio for cumulative severity (2.60), but its interval also fitted no association.

Participants

n=89 HYROX athletes (56 female). Age, experience and competitive level are not summarised in the abstract.

Protocol

OSTRC-H2 questionnaire weekly for 12 weeks, plus exposure reporting and a baseline questionnaire.
Exploratory risk markers (age, sex, previous injury, HYROX experience) for cumulative injury severity: negative binomial regression with an exposure offset.

Key Results

Mean weekly response rate 62%.
Pooled weekly prevalence of any health problem 30% (95% CI 24% to 37%); substantial problems 18% (95% CI 13%-24%).
Per 1,000 h there were 14.4 injuries (95% CI 11.1-18.4), and 6.4 time-loss injuries (95% CI 4.3-9.2); two thirds of episodes were put down to HYROX training (9.6 per 1,000 h).
Overuse injuries accounted for 73% of injuries.
Knee injuries were the most common (22% of episodes), and knee plus lower leg made up the largest burden; third for burden was the elbow, from just four episodes (two persistent); the shoulder was almost never injured.
A previous injury had the biggest rate ratio for cumulative severity — 2.60 (95% CI 1.00-6.75) — but the interval is also consistent with no association.
Only half of problems involved time-loss.

Practical Application

To "what gets injured in HYROX training?": in 89 HYROX athletes followed weekly for 12 weeks, about 30% had a health problem in any given week, injuries ran at 14.4 per 1,000 h, 73% were overuse, and the knee and lower leg carried the most burden — the running side of the sport, not the shoulders. Manage the running load first when a HYROX athlete reports niggles.
Only half of problems caused missed training, so "I haven't missed a session" does not mean "no problem"; the authors note time-loss counting understates the burden. Ask about pain and reduced training, not just days off.
An athlete with a previous injury is the one to watch (rate ratio 2.60), though the interval also fitted no association — a candidate marker, not a proven one.
Not from this paper; the base's own practice: a previous injury and high weekly running distance are the established running-injury risks in REF-564; the running-load progression in SYNTH-71 applies here.

Limitations

n=89 over 12 weeks with a 62% weekly response rate; region-level findings (elbow, shoulder) rest on a handful of cases, as the authors state.
The risk-marker analysis is exploratory and underpowered; the previous-injury interval includes no effect.
Self-reported questionnaire data; injury causes and diagnoses were not clinically confirmed in the abstract.
Competitive level, age and training volume of the cohort are not given in the abstract.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

small prospective cohort, n=89; the risk-marker analysis is exploratory