REF-742 · Protzen G, Inoue A, Buzzachera C, Doma K, Devantier-Thomas B, Herrero-Molleda A, García-López J, Boullosa D — 2026 · Sports Medicine – Open · Paper
Systematic review of 53 studies: contemporary Olympic cross-country MTB is an intermittent race at ~90% HRmax with about a quarter of the time above MAP in surges of ~3–10 s at 130–140% MAP, 15–20 per lap; Tier-5 men profile at VO₂max 82, MAP 6.6 W/kg and anaerobic peak 18 W/kg, and HIIT, SIT and strength training all raised race-relevant markers
Key Findings
Race demands: ~80–100 min; mean HR close to 90% HRmax; about a quarter of race time above MAP, interspersed with technical riding that keeps oxygen uptake high; a fast-start pacing profile with speed stabilising or slightly falling in later laps. Elite riders perform short surges of ~3–10 s at ~130–140% MAP, ~15–20 times per lap (≈8–9 W/kg in Tier-5 men).
Effort counts depend on the definition: Granier et al. counted ~18 efforts above MAP per lap of ~40 s each; Prinz et al. counted 334 efforts above MAP per race (~135% MAP), mean duration 4.3 s with 10.9 s between them.
Rider profiles (Tier 5, n = 32 men): VO₂max 82.3 ± 2.6 mL/kg/min, MAP 6.6 ± 0.3 W/kg, anaerobic peak power 17.9 ± 2.0 W/kg; Tier-5 women (n = 10): VO₂max 64.1 ± 6.3, MAP 5.2 ± 0.5 W/kg. Female data are scarce throughout.
Training interventions in XCO riders (Table 3 of the review): 8 months of 30-s all-out SIT added to regular training (2×/week, 4–6 × [4 × 30 s : 90 s]) → VO₂max +6%, MAP +5%, sprint power +4%; 6 weeks of HIIT (7–10 × 4–6 min) vs SIT (8–12 × 30 s all-out) → race time −5% vs −3%, peak power +8% vs +5%, HIIT ≈ SIT; 4 weeks of 20 s @ 115% MAP / 40 s @ 50% MAP (60–90 reps, 2×/week) → TT time −4%, MAP +8%, power at 4 mmol/L +13%.Strength training was also effective, but direct race-performance assessments of any intervention are scarce.
Practical Application
Build an off-road racer on two pillars, not one: a high aerobic ceiling (MAP / VO₂max via 4–6-min or short-short intervals) and repeatable supra-maximal power (30-s SIT or 20/40-type work) — both moved race-relevant markers in XCO riders, and the two formats were roughly equivalent head-to-head. A rider with only the ceiling fades on the bursts; a rider with only the sprint fades on the base.
Programme the surge pattern the review describes — 3–10 s at 130–140% MAP, 15–20 per lap, on a ~90% HRmax base — as the target of race-specific sessions (30/15s, bursts inside threshold, simulated laps), not just as a description.
Use it as the reference for cyclocross too, adjusted for duration: cross is shorter, has no descents and is even flatter in heart rate (REF-740, REF-741).
Limitations
MTB, not cyclocross; no cyclocross study met the review's criteria — the cross literature is essentially REF-740 plus one small power-test correlation.
Heterogeneous effort definitions and sampling rates make the burst counts hard to pool; the review reports ranges rather than a single number.
Female riders and Tier 1-2 amateurs are under-represented; the profile is an elite-male profile. Risk of bias: inclusion criteria and participant description were often poorly reported.
How this entry was checked and changed
Content correction 2026-09-27
Source note (truth pass): the numbers in this entry were taken from the paper's full text when it was ingested; many of them are not in the abstract. They were not re-checked against the full text on 2026-09-27.
Full text (checked 2026-10-12)
Of the 53 studies, 31 reported data exclusively on male athletes, 6 provided separate male and female data, 3 presented mixed data and 13 did not specify sex; 9 reported on Tier 5, 10 on Tier 4 and 37 on Tier 3 athletes (full text).
Tier-3 national-level men (n = 440) averaged VO₂max 63.9±2.2 mL·kg−1·min−1, MAP 4.9±0.8 W·kg−1 and anaerobic peak power 14.0±1.0 W·kg−1 (full text, Table 1).
Across race studies, time above MAP was 26±5% (Granier, real race), 30±9% (Prinz, men, real race) and 28±8% (Hays, simulated), with 25±5% to 28±4% of race time spent not pedalling (full text, Table 2).
In the HIIT vs SIT trial, both groups trained 3 sessions/week for 6 weeks, HIIT as 7–10 × (4–6 min @ maximal sustainable intensity : 4–6 min recovery) and SIT as 8–12 × (30 s all-out : 4 min recovery), in 16 Tier 3 riders whose sex was not specified (full text, Table 3).
Heavy strength training in 4 Tier 5 male riders raised leg-press force + 16% at 6 months, + 22% at 1.5 years and + 44% at 3.5 years, and sprint power up to + 25% at 3.5 years, while the endurance-only riders showed no changes (full text, Table 3).
The sprint-power gains from heavy strength training were maintained across competitive seasons by continuing it at approximately one session every 10 days (full text).
In a maximal-strength trial (8 weeks, 2×/week, then 1×/week), 1RM rose + 16% PRE→POST, while the endurance–strength group that stopped lost 1RM (− 16%) and sprint power (− 4%) MID→POST (full text, Table 3).