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Sankt Gallen, Switzerland

Eichenberger E.,University of Zurich | Knechtle B.,University of Zurich | Knechtle P.,Gesundheitszentrum St. Gallen | RuSt C.A.,University of Zurich | And 2 more authors.
Journal of Sports Sciences | Year: 2012

Little research has examined ultra-endurance swimming performances. The 'English Channel Swim', where swimmers have to cover a distance of 32 km between England and France represents a unique long-distance, open-water, sea-swimming challenge, and each year swimmers from all over the world try to succeed in this challenge. The best times in minutes and the nationality of successful men and women swimmers were analysed from 1900 to 2010. A total of 1,533 swimmers (455 women and 1,078 men) from more than 40 countries have successfully completed the 'English Channel Swim'. Great Britain was the country most represented, with 38% of the total, followed by the United States with 20%. Swim speed has increased progressively for both sexes (P < 0.001) but was lower for women than for men (0.68 ± 0.15 m · s-1 vs 0.71 ± 0.16 m · s-1 respectively, P < 0.01). However, the best annual performances did not differ between the sexes (men: 0.89 ± 0.20 m · s-1; women: 0.84 ± 0.18 m · s-1, P > 0.05). The results suggest that the performance of women open-water ultra-distance swimmers may be similar to that of men. Further studies investigating anthropometrical and physiological characteristics of open-water ultra-swimmers are needed to compare men's and women's open-water ultra-swim performances. © 2012 Copyright Taylor and Francis Group, LLC. Source

Stiefel M.,University of Zurich | Rust C.A.,University of Zurich | Rosemann T.,University of Zurich | Knechtle B.,Gesundheitszentrum St. Gallen
International Journal of General Medicine | Year: 2013

Background: Athletes intending to compete in Ironman Hawaii need to qualify in an age-group based qualification system. We compared participation and top ten performances of athletes in various age groups between Ironman Hawaii and its qualifier races. Methods: Finishes in Ironman Hawaii and in its qualifier races in 2010 were analyzed in terms of performance, age, and sex. Athletes were categorized into age groups from 18-24 to 75-79 years and split and race times were determined for the top ten athletes in each age group. Results: A higher proportion of athletes aged 25-49 years finished in the qualifier races than in Ironman Hawaii. In athletes aged 18-24 and 50-79 years, the percentage of finishes was higher in Ironman Hawaii than in the qualifier races. For women, the fastest race times were slower in Ironman Hawaii than in the qualifier races for those aged 18-24 (P < 0.001), 25-29 (P < 0.05), and 60-64 (P < 0.05) years. Swim split times were slower in Ironman Hawaii than in the qualifier races for all age groups (P < 0.05). Cycling times were slower in Ironman Hawaii for 18-24, 25-29, 40-44, 50-54, and 60-64 years (P < 0.05) in age groups. For men, finishers aged 18-24 (P < 0.001), 40-44 (P < 0.001), 50-54 (P < 0.01), 55-59 (P < 0.001), 60-64 (P < 0.01), and 65-69 (P < 0.001) years were slower in Ironman Hawaii than in the qualifier races. Swim split times were slower in Ironman Hawaii than in the qualifier races for all age groups (P < 0.05). Cycling times were slower in Ironman Hawaii for those aged 18-24 and those aged 40 years and older (P < 0.05). Conclusion: There are differences in terms of participation and performance for athletes in different age groups between Ironman Hawaii and its qualifier races. Triathletes aged 25-49 years and men generally were underrepresented in Ironman Hawaii compared with in its Ironman qualifier races. These athletes may have had less chance to qualify for Ironman Hawaii than female athletes or younger (<25 years) and older (>50 years) athletes. © 2013 Sohn, publisher and licensee Dove Medical Press Ltd. Source

Wagner S.,University of Zurich | Knechtle B.,University of Zurich | Knechtle P.,Gesundheitszentrum St. Gallen | Rust C.A.,University of Zurich | Rosemann T.,University of Zurich
European Journal of Applied Physiology | Year: 2012

We investigated the prevalence of exercise-associated hyponatremia (EAH) in 25 male and 11 female open-water ultra-endurance swimmers participating in the 'Marathon-Swim' in Lake Zurich, Switzerland, covering a distance of 26.4 km. Changes in body mass, fat mass, skeletal muscle mass, total body water, urine specific gravity, plasma sodium concentration [Na+] and haematocrit were determined. Two males (8%) and four females (36%) developed EAH where one female was symptomatic with plasma sodium [Na+] of 127 mmol/L. Body mass and plasma [Na+] decreased (p < 0.05). The changes in body mass correlated in both male and female swimmers to postrace plasma [Na +] (r = -0.67, p = 0.0002 and r = -0.80, p = 0.0034, respectively) and changes in plasma [Na+] (r = -0.68, p = 0.0002 and r = -0.79, p = 0.0039, respectively). Fluid intake was neither associated with changes in body mass, post-race plasma [Na+] or the change in plasma [Na +]. Sodium intake showed no association with either the changes in plasma [Na+] or post-race plasma [Na+]. We concluded that the prevalence of EAH was greater in female than in male open-water ultra-endurance swimmers. © Springer-Verlag 2011. Source

Knechtle B.,Gesundheitszentrum St. Gallen
The Chinese journal of physiology | Year: 2012

Ultra-endurance performance is of increasing popularity. We investigated the associations between anthropometry, training and support during racing, with race performance in 67 male recreational ultra-endurance cyclists participating in the 'Swiss Cycling Marathon' over 600 kilometres, an official qualifier for the cycling ultra-marathon 'Paris-Brest-Paris'. The 54 finishers showed no differences in anthropometry and did not train differently compared to the 13 non-finishers. During the race, the finishers were significantly more frequently racing alone than being followed by a support crew. After bivariate analysis, percent body fat (r = 0.43), the cycling distance per training unit (r = -0.36), the duration per training unit (r = -0.31) and the sleep time during the race (r = 0.50) were related to overall race time. The 23 non-sleepers in the finisher group completed the race within (mean and IQR) 1,567 (1,453-1,606) min, highly significantly faster than the 31 sleepers with 1,934 (1,615-2,033) min (P = 0.0003). No variable of support during the race was associated with race time. After multivariate analysis, percent body fat (P = 0.026) and duration per training unit (P = 0.005) remained predictor variables for race time. To summarize, for a successful finish in a cycling ultra-marathon over 600 kilometres such as the 'Swiss Cycling Marathon', percent body fat and duration per training unit were related to race time whereas equipment and support during the race showed no association. Athletes with naps were highly significantly slower than athletes without naps. Source

Knechtle B.,Gesundheitszentrum St. Gallen | Knechtle B.,University of Zurich | Knechtle P.,Gesundheitszentrum St. Gallen | Rosemann T.,University of Zurich
International Journal of Sports Physiology and Performance | Year: 2011

Purpose: Fluid overload is considered a main risk factor for exercise-associated hyponatremia (EAH). The aim of this study was to investigate the incidence of EAH in ultra-runners at the 100 km ultra-run in Biel, Switzerland. Methods: Pre- and postrace, body mass, urinary specific gravity, hemoglobin, hematocrit, plasma [Na +], and plasma volume were determined. Results: Of the 145 finishers, seven runners (4.8%) developed asymptomatic EAH. While running, the athletes consumed a total of (median and interquartile ranges) 6.9 (5.1-8.8) L over the 100 km distance, equal to 0.58 (0.41-0.79) L/h. Fluid intake correlated negatively and significantly with race time (r = -.50, P < .0001). Body mass decreased, plasma [Na +] remained unchanged, hematocrit and hemoglobin decreased, and urinary specific gravity increased. Plasma volume increased by 4.6 (-2.3 to 12.8) %. Change in body mass correlated with both postrace plasma [Na +] and Δ plasma [Na+]. Postrace plasma [Na +] correlated to Δ plasma [Na +]. Fluid intake was associated neither with postrace plasma [Na +] nor with Δ plasma [Na +]. Fluid intake was related to Δ body mass (r = .21, P = .012), but not to postrace body mass. Fluid intake showed no correlation to Δ plasma volume. Change in plasma volume was associated with postrace [Na +]. Conclusions: Incidences of EAH in 100 km ultra-marathoners were lower compared with reports on marathoners. Body mass decreased, plasma volume increased, and plasma [Na +] was maintained. Since fluid intake was related neither to Δ plasma volume nor to Δ plasma [Na +], we assume that factors other than fluid intake maintained body fluid homeostasis. © 2011 Human Kinetics Inc. Source

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