Beat Knechtle

Day 1

On May 8, 2026, the 3rd Eastern Switzerland Marathon Days kicked off with the tenth edition of the Arbon Marathon, held in beautiful spring weather.

Read more

The Comrades Marathon: A Narrative Review of Physiological Responses and Health Implications in the World's Oldest Ultra-Marathon

Background: The Comrades Marathon is the world’s oldest and largest ultra-marathon, held annually between Durban and Pietermaritzburg, South Africa, since 1921. As a nationally televised event with substantial participation, it provides a unique natural laboratory for studying the physiological demands of prolonged, high-intensity endurance running. This narrative review synthesizes current evidence on physiological responses, performance trends, and health implications associated with participation in the Comrades Marathon. Methods: A systematic search of EBSCO, PubMed, SciELO, and Web of Science identified studies published up to December 2025. Of 116 records retrieved, 42 publications (field studies and case reports) met eligibility criteria and focused specifically on the Comrades Marathon. Results: Women represented 4.2% of finishers, with female participation beginning in 1975. Growth in finishers during the 1970s was driven primarily by men aged 30–59 years. Men were consistently faster than women across all age groups, although the sex performance gap narrowed over time and overall performance improved. Peak performance occurred at ⁓29.9 years in men and ⁓36.0 years in women. Medical encounters occurred at rates up to 20 per 1000 starters. The most affected organ systems were fluid/electrolyte (8.8%; 8.3–9.4), central nervous system (4.0%; 3.7–4.5), and gastrointestinal (2.9%; 2.6–3.2). Dehydration (7.5%; 7.0–8.1) and exercise-associated muscle cramping (3.2%; 2.9–3.6) were the most common diagnoses. Exercise-associated hyponatremia was uncommon (<2%), whereas hypernatremia was substantially more prevalent. Early race editions reported isolated deaths, likely due to ischemic heart disease. Cardiac biomarker elevations and echocardiographic changes observed post-race were transient. The race induced muscle inflammation without major knee MRI abnormalities. In the 1970s, cases of acute kidney injury and renal failure occasionally required dialysis. Faster, well-trained runners showed higher rates of post-race upper respiratory tract infection than slower, less-trained runners. Conclusions: Participation in the Comrades Marathon is associated with well-characterized post-race physiological disturbances. Notably, the event demonstrates an unusually high prevalence of acute kidney injury and hypernatremia compared with other ultra-endurance races, underscoring the substantial renal and fluid–electrolyte stress imposed by prolonged, high-intensity running in challenging environmental conditions. These insights can inform individualized hydration strategies, targeted race preparation, and optimized medical support for ultra-endurance athletes.

Read more

Pacing profiles and slowdown patterns in ultra-triathlon performance

Pacing in long-distance triathlon has been studied primarily for cycling and running in IRONMAN triathlon and daily-format ultra-triathlons, as managing fatigue is critical for success. However, no study has analysed pacing across all three disciplines in an ultra-triathlon such as the second-longest non-stop triathlon format, the Double Deca Iron ultra-triathlon covering 76 km swimming, 3600 km cycling, and 844 km running. This study examined pacing during a Double Deca Iron ultra-triathlon by analysing split and lap times for all official male and female finishers. We assessed pacing patterns, the influence of pacing variability on performance, and whether faster performance was associated with more frequent moderate slowdowns or with fewer but more pronounced slowdowns. Official race data from the 2023 Swissultra Double Deca Iron ultra-triathlon held in Buchs, Switzerland were analysed for 9 men and 4 women. Swimming splits were recorded manually, and both cycling and running splits were recorded via RFID timing. Variables included mean speed, checkpoint speed variability (ACCS), proportions of slow-down checkpoints (25–50%, 50–75%, > 75% slower than mean speed), and magnitude of slowdown. Athletes showed negative pacing in swimming (decreasing time) but an even or slightly positive pacing in both cycling and running. Running variability did not correlate with running speed. In swimming, faster athletes tended to show fewer relative slowdowns. In cycling, faster cyclists had fewer moderate but more pronounced slowdowns, while in running, faster runners showed more ≥ 75% slowdowns. In summary, higher performers maintained a relatively steady and fast baseline pace interspersed with occasional substantial slowdowns, rather than moving continuously at a slower and more variable pace. Because the timing data do not directly identify intentional rest, these slowdown patterns should not be interpreted as confirmed rest breaks.

Read more