Sankt Gallen, Switzerland
Sankt Gallen, Switzerland

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Haupt S.,University of Zürich | Knechtle B.,University of Zürich | Knechtle P.,Facharzt FMH fur Allgemeinmedizin | Rust C.A.,University of Zürich | And 2 more authors.
Research in Sports Medicine | Year: 2013

The age-related changes in ultraendurance performance have been previously examined for running and triathlon but not mountain biking. The aims of this study were (i) to describe the performance trends and (ii) to analyze the age-related performance decline in ultraendurance mountain biking in a 120-km ultraendurance mountain bike race the "Swiss Bike Masters" from 1995 to 2009 in 9,325 male athletes. The mean (±SD) race time decreased from 590 ± 80 min to 529 ± 88 min for overall finishers and from 415 ± 8 min to 359 ± 16 min for the top 10 finishers, respectively. The mean (±SD) age of all finishers significantly (P < 0.001) increased from 31.6 ± 6.5 years to 37.9 ± 8.9 years, while the age of the top 10 remained stable at 30.0 ± 1.6 years. The race time of mountain bikers aged between 25 and 34 years was significantly (P < 0.01) faster compared with the race time of older age groups. The age-related decline in performance in endurance mountain bikers in the "Swiss Bike Masters" appears to start earlier compared with other ultraendurance sports. © 2013 Copyright Taylor and Francis Group, LLC.


Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Knechtle B.,University of Zürich | Rust C.A.,University of Zürich | Rosemann T.,University of Zürich | Lepers R.,University of Burgundy
Age | Year: 2012

The aims of this study were (1) to investigate the participation and performance trends at the '100 km Lauf Biel' in Switzerland from 1998 to 2010, and (2) to compare the age-related changes in 100-km running performance between males and females. For both sexes, the percent of finishers significantly (P<0.01) decreased for the 18-29 and the 30-39-year age groups, while it significantly (P<0.01) increased for the 40-49 and the 50-59-year age groups over the studied period. From 1998 to 2010, the mean age of the top ten finishers increased by 0.4 years per annum for both females (P=0.02) and males (P=0.003). The running time for the top ten finishers remained stable for females, while it significantly (P=0.001) increased by 2.4 min per annum for males. There was a significant (P<0.001) age effect on running times for both sexes. The best 100-km running times was observed for the age comprised between 30 and 49 years for males, and between 30 and 54 years for females, respectively. The age-related decline in running performance was similar until 60-64 years between males and females, but was greater for females compared to males after 65 years. Future studies should investigate the lifespan from 65 to 75 years to better understand the performance difference between male and female master ultra-marathoners. © The Author(s) 2011.


Etter F.,University of Zürich | Knechtle B.,University of Zürich | Bukowski A.,Facharzt FMH fur Allgemeinmedizin | Rust C.A.,University of Zürich | And 2 more authors.
Journal of Sports Sciences | Year: 2013

This study investigated the participation and performance trends as well as the age and gender interaction at the Olympic distance 'Zürich Triathlon' (1.5 km swim, 40 km cycle and 10 km run) from 2000 to 2010 in 7,939 total finishers (1,666 females and 6,273 males). Female triathletes aged from 40 to 54 years significantly (P < 0.05) increased their participation while the participation of younger females and males remained stable. Males of 50-54 years of age and females of 45-49 years of age improved their total race time. For elite top five overall triathletes, mean gender differences in swimming, cycling, running and overall race time were 15.2 ± 4.6%, 13.4 ± 2.3%, 17.1 ± 2.5%, and 14.8 ± 1.8%, respectively. For both elite and age group athletes, the gender difference in cycling time was significantly (P <0.001) lower than for swimming and running. The gender difference in overall Olympic distance triathlon performance increased after the age of 35 years, which appeared earlier compared to long distance triathlon as suggested by previous studies. Future investigations should compare gender difference in performance for different endurance events across age to confirm a possible effect of exercise duration on gender difference with advancing age. © 2013 Copyright Taylor and Francis Group, LLC.


Rust C.A.,University of Zürich | Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Rosemann T.,University of Zürich | Lepers R.,University of Burgundy
Applied Physiology, Nutrition and Metabolism | Year: 2014

In La Traversée Internationale du Lac St-Jean, held between 1955 and 2012 in Canada, the fastest women (r2 = 0.61, p < 0.0001) and men (r2 = 0.66, p < 0.0001) improved swimming speed over the years but the sex difference remained unchanged at 8.8% ± 5.6% (r2 = 0.069, p = 0.065). Annually, for the 3 fastest swimmers, both women (r2 = 0.53, p < 0.0001) and men (r2 = 0.71, p < 0.0001) improved swimming speed between 1973 and 2012 and the sex difference decreased (r2 = 0.29, p = 0.0016) from 14.4% ± 11.0% (1973) to 3.7% ± 1.4% (2012).


Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Knechtle B.,University of Zürich | Knechtle P.,Facharzt FMH fur Allgemeinmedizin | Lepers R.,University of Burgundy
Scandinavian Journal of Medicine and Science in Sports | Year: 2011

We examined the changes in participation and performance trends in ultra-triathlons, from the Double Iron (7.6km swimming, 360km cycling, 84.4km running) to the Deca Iron (38km swimming, 1800km cycling, 422km running), between 1985 (first year of a Double Iron) and 2009 (25 years). The mean finish rate for all distances and races was 75.8%. Women accounted for ∼8-10% of the ultra-triathlons starters. For Double and Triple Iron, the number of finishers per year increased, from 17 to 98 and from 7 to 41, respectively. In the Deca Iron, the finishers per race have remained <20 since the first event was held, up to 2009. Concerning World best performances, the men were ∼19% faster than the women in both the Double and Triple Iron, and ∼30% faster in a Deca Iron. With the increasing length of ultra-triathlons, the best women became relatively slower compared with the best men. Further investigations are required to understand why this gender difference in total performance time increased with the distance in ultra-triathlons. © 2010 John Wiley & Sons A/S.


Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Knechtle P.,Facharzt FMH fur Allgemeinmedizin | Christoph A.R.,Institute of General Practice and for Health Services Research | Rosemann T.,Institute of General Practice and for Health Services Research
Journal of Sports Sciences | Year: 2011

We examined differences in anthropometry and training between 64 Triple Iron ultra-triathletes competing over 11.4 km swimming, 540 km cycling, and 126.6 km running, and 71 Ironman triathletes competing over 3.8 km swimming, 180 km cycling, and 42.2 km running. The association of anthropometry and training with race time was investigated using multiple linear regression analysis. The Triple Iron ultra-triathletes were smaller (P < 0.05), had shorter limbs (P < 0.05), a higher body mass index (P < 0.05), and larger limb circumferences (P < 0.01) than the Ironman triathletes. The Triple Iron ultra-triathletes trained for more hours (P < 0.01) and covered more kilometres (P < 0.01), but speed in running during training was slower compared with the Ironman triathletes (P < 0.01). For Triple Iron ultra-triathletes, percent body fat (P = 0.022), training volume per week (P < 0.0001), and weekly kilometres in both cycling (P < 0.0001) and running (P< 0.0001) were related to race time. For Ironman triathletes, percent body fat (P < 0.0001), circumference of upper arm (P=0.006), and speed in cycling training (P = 0.012) were associated with total race time. We conclude that both Triple Iron ultra-triathletes and Ironman triathletes appeared to profit from low body fat. Triple Iron ultra-triathletes relied more on training volume in cycling and running, whereas speed in cycling training was related to race time in Ironman triathletes. © 2011 Taylor & Francis.


Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Knechtle B.,University of Zürich | Knechtle P.,Facharzt FMH fur Allgemeinmedizin | Rosemann T.,University of Zürich
Physician and Sportsmedicine | Year: 2010

Aims: In a recent study of male ultra-marathoners who participated in a 161-km ultra-run, the prevalence of exercise-associated hyponatremia (EAH) was reported to be 50%, which is a considerably higher percentage than that seen in marathoners. We investigated the prevalence of EAH in male ultra-marathoners competing in a 24-hour run held in Basel, Switzerland. Body weight, hematocrit levels, plasma volume, plasma sodium concentration, urine specific gravity, and fluid intake were recorded in 15 male ultra-marathoners (mean age ± standard deviation [SD], 46.7 [5.8] years; plasma sodium, 71.1 [6.8] kg; height, 1.76 [0.07] m; body weight, 23.1 [1.84] kg/m2). Plasma sodium was measured at 135.3 (2.8) mmol/L before the race and remained unchanged at 135.4 (3.6) mmol/L after the race. The competitors consumed a total of 15.1 (5.1) L during the race, equal to 0.62 (0.21) L/hour. Fluid intake correlated to the mean running speed (r = -0.87; P = 0.0001). Body weight decreased significantly (P = 0.0009) by 2.2 kg. Hematocrit remained unchanged, and urine specific gravity increased significantly (P = 0.0005). Plasma volume increased by 4.9% (15.8%). Changes in body weight showed no association with post-race plasma sodium. The normal resting value should be 140 mmol/L so that a decrease of 5 mmol/L is described as EAH. Because the starting plasma sodium in this study was 135 mmol/L, it is not possible to define EAH as a value that is < 135 mmol/L. Instead, the correct definition should be a plasma sodium concentration of 130 mmol/L (ie, 5mmol/L below the normal resting value). Following this definition, it was determined that no athlete developed EAH in this 24-hour run. © The Physician and Sportsmedicine.


Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Knechtle B.,University of Zürich | Knechtle P.,Facharzt FMH fur Allgemeinmedizin | Kohler G.,University of Basel
Research in Sports Medicine | Year: 2011

We evaluated the change in body mass including fat mass and skeletal muscle mass in one ultracyclist whilst cycling 1,000 km in 48 hours at a constant intensity of ∼48% VO2max, corresponding to a heart rate frequency of ∼105 ± 5 bpm. A 1 kg fat mass decrease resulted, with the largest decrease occurring between the 12th and the 24th hour. No steady state in metabolism was observed and no regular decrease of subcutaneous adipose tissue resulted. This result is backed up by the nuclear magnetic resonance (NMR) urine analysis. Body water increase with simultaneous dehydration is possibly due to endocrine-induced renal water retention, in order to maintain metabolism processes that are required for energy supply and blood flow during very prolonged exercise. Both applied methods, the anthropometric and the bioelectrical impedance analysis, analyse fluid accumulation-especially in the skinfolds of the lower extremities-apparently incorrectly as an increase in body mass and not as an increase in fluids. Copyright © Taylor & Francis Group, LLC.


Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Knechtle P.,Facharzt FMH fur Allgemeinmedizin | Wirth A.,Facharzt FMH fur Allgemeinmedizin | Alexander Rust C.,University of Zürich | Rosemann T.,University of Zürich
Journal of Sports Sciences | Year: 2012

In 219 recreational male runners, we investigated changes in body mass, total body water, haematocrit, plasma sodium concentration ([Na+]), and urine specific gravity as well as fluid intake during a 100-km ultra-marathon. The athletes lost 1.9 kg (s = 1.4) of body mass, equal to 2.5% (s = 1.8) of body mass (P < 0.001), 0.7 kg (s = 1.0) of predicted skeletal muscle mass (P < 0.001), 0.2 kg (s = 1.3) of predicted fat mass (P < 0.05), and 0.9 L (s = 1.6) of predicted total body water (P < 0.001). Haematocrit decreased (P < 0.001), urine specific gravity (P < 0.001), plasma volume (P < 0.05), and plasma [Na+] (P < 0.05) all increased. Change in body mass was related to running speed (r = -0.16, P < 0.05), change in plasma volume was associated with change in plasma [Na+] (r = -0.28, P < 0.0001), and change in body mass was related to both change in plasma [Na+] (r = -0.36) and change in plasma volume (r = 0.31) (P < 0.0001). The athletes consumed 0.65 L (s = 0.27) fluid per hour. Fluid intake was related to both running speed (r = 0.42, P < 0.0001) and change in body mass (r = 0.23, P = 0.0006), but not post-race plasma [Na+] or change in plasma [Na+] (P > 0.05). In conclusion, faster runners lost more body mass, runners lost more body mass when they drank less fluid, and faster runners drank more fluid than slower runners. © 2012 Copyright Taylor and Francis Group, LLC.


Knechtle B.,Facharzt FMH fur Allgemeinmedizin | Knechtle B.,University of Zürich | Knechtle P.,Facharzt FMH fur Allgemeinmedizin | Rosemann T.,University of Zürich
European Journal of Applied Physiology | Year: 2011

We investigated the prevalence of exercise-associated hyponatremia (EAH) in 145 male ultra-marathoners at the '100-km ultra-run' in Biel, Switzerland. Changes in body mass, urinary specific gravity, haemoglobin, haematocrit, plasma [Na +], and plasma volume were determined. Seven runners (4.8%) developed asymptomatic EAH. Body mass, haematocrit and haemoglobin decreased, plasma [Na +] remained unchanged and plasma volume increased. Δ body mass correlated with both post race plasma [Na +] and Δ plasma [Na +]. Δ plasma volume was associated with post race plasma [Na +]. The athletes consumed 0.65 (0.30) L/h; fluid intake correlated significantly and negatively (r = -0.50, p < 0.0001) to race time. Fluid intake was neither associated with post race plasma [Na +] nor with Δ plasma [Na +], but was related to Δ body mass. To conclude, the prevalence of EAH was low at ∼5% in these male 100 km ultra-marathoners. EAH was asymptomatic and would not have been detected without the measurement of plasma [Na +]. © 2010 Springer-Verlag.

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