The age of the best marathon performance has been well investigated for flat city marathon running, but not for mountain marathon running. The aim of this study was to determine the age of the best mountain marathon performance and to compare to results of a flat city marathon. Race times and ages of finishers of a mountain marathon with 1,830 m of altitude change (Jungfrau Marathon, Switzerland) and two flat city marathons (Lausanne Marathon and Zurich Marathon, Switzerland) were analysed using linear, non-linear and mixed-effects regression analyses. Race times were slower in the mountain compared to the city marathon. In both the mountain marathon and the city marathons, women and men improved performance and men were faster than women when the fastest per year and all per year were considered. When the fastest runners in 1-year age intervals were considered in the mountain marathon, the fastest man (3:01 h:min) was ~35.6 years and the fastest women (3:28 h:min) ~34.5 years old. When all finishers were considered in 1-year age intervals, the fastest men (4:59 h:min) were ~29.1 years old and the fastest women (5:16 h:min) were ~25.6 years old. In the city marathons in 1-year age intervals, the fastest man (2:10 h:min) was ~23.7 years old and the fastest woman (2:36 h:min) ~32.2 years old. When all finishers were considered in 1-year age intervals, the fastest men (3:41 h:min) were ~35.0 years old and the fastest women (4:00 h:min) ~33.8 years old. In summary, the age of the fastest women and men was higher in the mountain marathon compared to the city marathons when the fastest runners were considered. However, when all finishers were considered the age of the fastest women and men was lower in the mountain marathon compared to the city marathons.
