Sports and recreation
Mountain biking
Estimated acute risk associated with recreational off-road mountain biking.
Base risk estimate
0.15 micromorts per hours
Population-level estimate. Not a personal prediction.
Assumptions
Assumes recreational off-road mountain biking on singletrack or bike-park terrain. Off-road crash fatalities only — road traffic deaths involving cyclists are not included.
Limitations
Norwegian registry data may not generalize directly to US conditions (trail standards, helmet culture, emergency access differ). The US off-road MTB fatality estimate is derived indirectly from NHTSA total cycling deaths. Exposure (national mountain biking hours) is estimated from SFIA participation data, not directly measured. Risk varies by trail difficulty, speed, helmet and protective gear use, and remoteness.
Source notes
Derived from Norwegian registry data (Heir T et al., Injury Epidemiology 2024) and SFIA US participation data. Heir et al. identified 97 mountain biking fatalities over 16 years in Norway using national cause-of-death registry data, averaging approximately 6 fatalities/year. Applying estimated Norwegian mountain biking exposure (approximately 700,000–900,000 participants × 20 outings × 2 hours = ~30 million hours/year) yields approximately 0.2 µmt/hour for the Norwegian population. Cross-reference with US data: NHTSA 2022 Traffic Safety Facts documents approximately 1,000 total US cyclist fatalities; the large majority are road traffic deaths. Off-road mountain biking crash fatalities (falls, collisions with terrain features) are a small subset estimated at 40–80/year. SFIA 2022 reports approximately 8.5 million US mountain biking participants; at an estimated 15 outings/year × 2 hours = ~255 million MTB hours, yielding a US-derived rate of 0.16–0.31 µmt/hour. Using 0.15 µmt/hour as a conservative central estimate consistent with both datasets. The prior placeholder of 0.02 µmt/hour was inconsistent with both the Norwegian registry data and the US NHTSA/SFIA comparison.
Last reviewed
6/11/2026
How does this compare?
Activities with a similar per-unit risk level. Units vary — these are approximate comparisons.
Related activities
RiskLens is an educational tool. It uses population-level estimates to help explain relative risk. It is not a prediction of your personal risk and should not be used as medical, legal, financial, or safety advice.