REF-703 · Hebisz et al., 2022 · International Journal of Environmental Research and Public Health, · Paper
Creatine kinase and myoglobin 1 h after a race in mountain-bike vs road cyclists
Damage markers relate to performance in opposite directions by discipline
Participants
Male U23 cyclists, n=25 in total: 11 mountain bike, 14 road, each following their own respective race. Aerobic capacity (VO₂max, maximal aerobic power) assessed separately by incremental test.
Protocol
Blood drawn 2 h before and 1 h after the race for creatine kinase activity (CK) and myoglobin concentration (MB); pre-post deltas computed (ΔCK, ΔMB). Each rider's finishing time was recorded and the time difference from the winner (TD) calculated, then related to the deltas.
Key Findings
Muscle damage markers rise measurably after a real bike race — both CK (p=0.001, η²=0.40) and MB (p<0.001, η²=0.43) increased across the whole sample. This is the core PMEP-5 claim in cycling: damage is not a running-only phenomenon.
The rise is discipline-specific: post-race CK increased only in road cyclists; post-race MB increased only in mountain bikers.
The performance relationship runs in OPPOSITE directions by discipline: smaller time gaps to the winner were associated with lower ΔMB in road cyclists, but with higher ΔCK in mountain bikers.
Practical Application
**In 25 male U23 cyclists (11 MTB, 14 road) sampled 2 h before and 1 h after their own race, CK and myoglobin rose overall; CK rose only in road riders and myoglobin only in mountain bikers, and the link to the time gap to the winner ran in opposite directions (smaller gap with lower ΔMB on the road, with higher ΔCK in MTB).Treat a post-race CK/MB spike as a load signature, not automatically as a fault.** In the MTB cohort the better-placed riders were the *more* damaged ones — consistent with the simple reading that the strongest riders did the most work.
Do not use a single damage marker as a standalone "durability score". Its direction depends on discipline and on what the race demanded (sustained road effort vs repeated impacts and surges off-road).
Where markers are used at all, use them within-athlete over time at a comparable event, never as a cross-athlete ranking.
Limitations
Small, young, single-sex samples (n=11 and n=14, U23 men).
Observational and cross-sectional — associations between a marker delta and finishing position cannot separate "damage cost me time" from "I was strong enough to do more work and therefore accrued more damage". The MTB result makes this ambiguity explicit.
One post-race sampling point (1 h); CK in particular peaks much later, so the 1 h delta understates the eventual response.
Fact-check note (not from this paper's abstract): a secondary source (Knowledgeiswatt PMEP-5 newsletter, Jul 2026) attributes to this paper the claim that a myoglobin rise "explained 58% of the time gap to the race winner" in a 141 km road race. That figure does not appear in the published abstract, whose own framing is directional only — and inverted in the MTB group. Treat the 58% as unverified; do not repeat it without the full text.
How this entry was checked and changed
Content correction 2026-09-27
Participants line now gives the total sample first (n=25: 11 MTB, 14 road) so the parsed n is the whole study, not the MTB subgroup.
Lead ▶ line now states the study's finding (population, sampling, discipline-specific direction) before the practical reading.
The unverified "58% / 141 km" secondary-source figure is now explicitly labelled as not from this paper's abstract; all other numbers, directions and the discipline-specific findings checked against the abstract and kept.