TransPyrenea 900 km is a mountain ultratrail covering 898 km with 55,000 meters of climbing across the Pyrenees. Participants have up to 400 hours, approximately sixteen days, making it more akin to a long expedition on foot than a short trail race. The event features about 350 international athletes and tests sleep management, sustained climbing, and the mental fortitude required for multi-day efforts.
The race also serves as a research project into extreme endurance. TRM, a trail-running training and services company, directs the study alongside two Italian National Research Council institutes, a university research center, and a private nutrition research company. Forty-eight chosen international runners, along with two TRM Endurance Team professionals, will be monitored to collect data on psycho-physical performance, training strategies for events over 330 km, and trail-running gear under actual race conditions.