Sex Differences in Training Behaviors of 10 km to Ultra-Endurance Runners (Part A)—Results from the NURMI Study (Step 2)

Training for running events is fundamental for successful participation in various running events such as 10 km, half-marathon, marathon, or ultra-marathon distances. Training behaviors are likely based on runner motivations and social constraints, particularly for females. Participants completed a questionnaire following a cross-sectional approach, including questions on sociodemographics, general training behaviors, and periodization training strategies. The final sample included 245 participants (141 females, 104 males), mostly from Germany (72%), Austria (18%), and Switzerland (5%), with a median age of 39 years (IQR 17) and a BMI of 21.7 kg/m² (IQR 3.5). Males more often trained alone and independently, whereas females were most likely to follow an external resource (p = 0.037). Non-parametric ANOVA revealed significant training differences between sexes in daily training mileages and durations at each phase and stage (p < 0.05) as well as in weekly training mileages and durations for general basic training and race-specific training (p < 0.05). Critical sex differences in training behaviors may arise from physiological differences and social expectations, which may be related to the distances they prefer to race at as well as their motivations for running and racing. This study provides a wide overview of training behaviors for endurance runners or professionals guiding healthy running performance.