Beat Knechtle

Performance, physiology, and determinants of success in IRONMAN® 70.3: A systematic review

IRONMAN® 70.3 events represent a rapidly expanding endurance discipline characterized by distinct physiological demands, performance determinants, and race-specific risk profiles. Despite their global popularity, no systematic review has synthesized evidence exclusively focused on this distance. To consolidate current knowledge on performance predictors, physiological responses, training characteristics, nutritional strategies, environmental influences, and medical considerations in IRONMAN® 70.3 triathletes, and to identify gaps requiring further investigation. A systematic search of PubMed, Scopus, SciELO, EBSCO and Google Scholar was conducted up to 25th November 2025. Search terms were developed according to PRISMA guidelines and included variations of ‘Ironman 70.3’, ‘half triathlon’ and ‘middle-distance triathlon’. Eligible studies reporting physiological, anthropometric, nutritional, environmental, medical, or performance-related outcomes specific to IRONMAN® 70.3. Risk of bias was assessed using the Newcastle–Ottawa Scale, the Cochrane RoB tool, and the NIH Quality Assessment Tool, according to study design. A total of 86 studies were included, predominantly observational in design, with sample sizes ranging from 1 to 852,721 participants, mostly trained male triathletes aged 25–39 years. Participation has increased across age groups, with pronounced growth among female and masters triathletes. Peak performance in professional male triathletes is reached at approximately age 28, and in female triathletes at age 32. Across large datasets, cycling appeared to be the strongest predictor of overall race time, accounting for the largest proportion of performance variance. Physiologically, competition was associated with transient reductions in immune function, reversible muscle damage, and shifts in hydration and electrolyte balance, while higher intracellular water and efficient fat oxidation were associated with better outcomes. Evidence specific to IRONMAN® 70.3 is limited by small sample sizes, heterogeneous designs, male-dominated cohorts, and insufficient sex-specific analyses. Future research should distinguish recreational from elite triathletes, incorporate balanced sex representation, and apply standardized physiological and environmental monitoring to refine targeted recommendations for performance, health, and safety.

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Sex differences in marathon pacing: analysis of 873,000 Berlin marathon runners reveals men are twice as likely to “hit the wall”

To determine whether sex differences in marathon pacing strategies and susceptibility to catastrophic deceleration (“hitting the wall”) persist in a massive, high-performance dataset, and to quantify this risk across different performance levels. We analyzed 873,334 finishers from the Berlin Marathon (1999–2025). Pacing stability was quantified using the percentage slowdown in the second half relative to the first. “Hitting the wall” was operationally defined as a deceleration of ≥ 20%. A stratified analysis was performed to compare risks between sexes across five performance categories (Competitive to Casual). Multivariable logistic regression adjusted for age and performance category, sensitivity analyses (deduplicated subset; alternative thresholds), and fine-grained pacing metrics from 5 km splits were also conducted. Male runners exhibited significantly greater mean deceleration (10.73% ± 11.41%) compared with female runners (8.34% ± 8.91%, p < 0.001). The prevalence of “hitting the wall” was nearly double in men (17.63%) compared with women (9.66%), corresponding to a crude Odds Ratio of 2.00 (95% CI 1.97 to 2.03); after adjustment for age and performance category, the disparity strengthened (adjusted OR = 3.88, 95% CI 3.81 to 3.94). The risk disparity widened among the fastest runners: in the Competitive (< 3 h) category, male runners were approximately six times more likely to experience catastrophic deceleration than their female counterparts (1.42% vs 0.23%). The gap was stable across the 27-year archive (Mann–Kendall τ = 0.14, p = 0.33). Despite faster finish times, men demonstrate significantly less stable pacing strategies and a twofold higher crude risk of catastrophic deceleration compared with women, with the disparity most pronounced among the fastest runners. These findings are consistent with the hypothesis that behavioral and strategic factors contribute alongside physiological determinants to sex differences in marathon outcomes, and provide a quantitative basis for further investigation of the underlying mechanisms. Sex differences in marathon pacing: analysis of 873,000 Berlin marathon runners reveals men are twice as likely to “hit the wall” | Scientific Reports

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Sleep quality and psychological interactions in endurance and ultra-endurance trail runners: A prospective cross-sectional study

Endurance and ultra-endurance running impose substantial physical and psychological demands, leading athletes to experience intense emotional states before, during, and after competitions. Accordingly, there is a paucity of evidence comparing mood profiles between endurance and ultra-endurance runners competing in trail and mountain events. The aim of this study was to characterize the mood profile of endurance and ultra-endurance runners participating in La Misión Brasil 2024 and to analyze its relationship with sleep quality. This prospective cross-sectional study included 193 runners, divided into an endurance group (n = 118; men = 75; women = 43) and an ultra-endurance group (n = 75; men = 60; women = 15), who participated in the same competition according to the proposed distances. La Misión Brasil is a trail running event with race distances ranging from 25 to 80 km and substantial elevation gain. One week prior to the competition, participants completed questionnaires assessing mood state, anxiety, psychological health, and sleep quality. Comparisons between groups (endurance group vs. ultra-endurance group) and sexes were performed using independent t-tests, Mann–Whitney tests, and generalized linear models, whereas associations were examined using Spearman’s correlation. The results indicated higher vigor levels in the ultra-endurance group (p = 0.020) and greater overall fatigue in the endurance group (p = 0.027). Regarding sex differences, men exhibited higher vigor (p = 0.004), whereas women presented higher total mood disturbance and anxiety scores (trait anxiety and state anxiety; p < 0.05). Correlational analyses revealed that poorer sleep quality scores were moderately associated with higher total mood disturbance (r2 = 0.45) and anxiety levels (trait anxiety: r2 = 0.47; state anxiety: r2 = 0.48). Additionally, strong correlations were observed between negative mood states, total mood disturbance, and anxiety (r2 > 0.50). Overall, endurance and ultra-endurance runners demonstrated a favorable mood profile; however, the psychological demands of these modalities are associated with relevant interactions between sleep, mood, and anxiety.

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