REF-859 · Wirnitzer & Kornexl, 2008 · European Journal of Applied Physiology, Vol. · Paper · PubMed

Exercise intensity during an 8-day mountain bike marathon race

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

Seven amateur mountain bikers who completed the Transalp Challenge 2004, an 8-day mountain bike marathon stage race, had four heart-rate intensity zones set from fixed blood lactate thresholds in a pre-race laboratory test and wore heart-rate monitors throughout the race.

Mean heart rate was 85.4% of the maximal heart rate seen in the race, or 79.2% of the laboratory maximum, and 36% of total race time was spent in the high and very-high intensity zones. The authors conclude the race is very demanding and heavily involves both aerobic and anaerobic energy systems.

Participants

n=7 amateur mountain bikers (abstract: "Seven amateur MTBers"): age 33.6 ± 3.0 years, height 1.67 ± 0.5 m (standard deviation as printed), body mass 58.4 ± 9.9 kg. Sex is not stated in the abstract.

Protocol

Before the race: maximal incremental cycling test; four intensity zones set from the heart rates at fixed blood lactate thresholds of 2, 4 and 6 mmol/L.
During the Transalp Challenge 2004 (8 days): heart rate recorded with short-range telemetry systems.

Key Results

Mean heart rate: 85.4% of the maximal heart rate during the race, or 79.2% of the laboratory-determined maximum.
Time in the high and very-high intensity zones: 36% of total race time (abstract: "Thirty-six percent").
The abstract does not give daily stage durations, the time in the lower zones, or day-to-day changes.

Practical Application

In seven amateur mountain bikers racing the 8-day Transalp Challenge, heart rate averaged 79.2% of the laboratory maximum (85.4% of the highest heart rate seen in the race), and 36% of all race time was spent in the high and very-high zones set from the 2, 4 and 6 mmol/L lactate thresholds. To "how hard is a multi-day mountain bike stage race?": hard: about a third of the riding sat in the upper zones, day after day.
Contrast with road ultra-cycling: in a day-long mountain road race, most of the time was spent at moderate heart rates REF-797. Inference, not tested here: a marathon MTB stage race is not paced like a road ultra, because short stages and terrain force hard efforts.
Inference, not tested here: the high and very-high zones are presumably those above the 4 mmol/L heart rate (the zone labels are not defined in the abstract). Preparation for such a race needs repeated hard days on consecutive days, not only long easy volume.
Not from this paper; the base's own practice: preparing a single-day marathon MTB or gran fondo is in SYNTH-50; multi-day eating and sleep in SYNTH-63.

Limitations

n=7, one edition of one race; sex not stated.
Heart rate only: no power, so the intermittent demand is seen only through a lagging, fatigue-sensitive signal.
The height standard deviation (0.5 m) as printed is implausible for this group and is probably a typographical error in the abstract.
The zone boundaries' labels, stage lengths and day-by-day data are not 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

descriptive, n=7, one race