JOURNAL OF SPORTS SCIENCE & MEDICINE
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Research article
 

A MULTI-STAGE ULTRA-ENDURANCE RUN OVER 1,200 KM LEADS TO A CONTINUOUS ACCUMULATION OF TOTAL BODY WATER

Beat Knechtle1,2, Brida Duff1, Ingo Schulze3 and Götz Kohler4

1Gesundheitszentrum St. Gallen, St. Gallen, Switzerland, 2Department of General Practice, University of Zürich, Zürich, Switzerland, 3Deutschlandlauf, Horb-Nordstetten, Germany, 4Division of Biophysical Chemistry, Biozentrum, University of Basel, Basel, Switzerland

Received   06 March 2008
Accepted   27 June 2008
Published   01 September 2008

© Journal of Sports Science and Medicine (2008) 7, 357 - 364
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ABSTRACT  
We determined whether ultra-runners in a multi-stage ultra- endurance run lose body mass, fat mass, skeletal muscle mass or total body water in a descriptive field study at the 'Deutschlandlauf' 2007 a 1,200 km run within 17 consecutive days with 10 male non-professional Caucasian ultra-runners (mean ± SD, 43.8 ± 6.2 years, 73.8 ± 6.0 kg body mass, 1.77 ± 0.05 m body height, BMI 23.3 ± 1.8 kg·m-2). Body mass, fat mass, skeletal muscle mass, lean body mass and percent total body water were determined using bioelectrical impedance analysis and the anthropometric method before the race and after each stage. In addition, urinary specific gravity was measured in order to quantify hydration status. Fat mass (bioelectrical impedance analysis) decreased by 3.9 kg (p < 0.05), skeletal muscle mass (anthropometric method) decreased by 2.0 kg (p < 0.05) whereas percent total body water increased by 6.1 % (p < 0.05) by the end of the race. Ultra-runners in a multi-stage ultra-endurance event over 1,200 km, with 17 consecutive stages, showed a cumulative increase in percent total body water, a decrease in skeletal muscle mass and a decrease in fat mass, depending upon the method used. We presume that the eccentric component of running leads to damage of skeletal muscle, leading to rhabdomyolysis, with impaired renal function.

Key words: Body fat - body mass - dehydration - skeletal muscle mass.

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