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A multi-stage ultra-endurance triathlon leads to a decrease of body fat but not of skeletal muscle mass – the World Challenge Deca Iron 2006
  1. Beat Knechtle (beat.knechtle{at}
  1. Gesundheitszentrum St. Gallen, Switzerland
    1. Oscar Fraire Salas (ekosaar{at}
    1. Universidad Autónoma de Nuevo León, Monterrey, Mexico
      1. Jorge Luis Andonie (jlandonie{at}
      1. Multisport Andonie, Monterrey, Mexico
        1. Götz Kohler (goetz.kohler{at}
        1. Division of Biophysical Chemistry, Biozentrum, University of Basel, Basel, Switzerland


          Objective: To investigate the effect of a multi-stage ultra-endurance triathlon on body composition in ultra-triathletes. Design: Descriptive field study.

          Setting: The “World Challenge Deca Iron Triathlon 2006” in Monterrey, Mexico, where, every day, athletes had to perform the distance of one Ironman triathlon within 10 consecutive days. Subjects: Eight male ultra-endurance athletes (mean ± SD, 40.6 ± 10.7 years, 76.4 ± 8.4 kg, 175 ± 4 cm, BMI 24.7 ± 2.2 kg/m2).

          Interventions: None. Main Outcome Measurements: Determination of body mass, protein mass, body fat, percent body fat, mineral mass, total body water, intracellular water, extracellular water and lean body mass with a direct segmental multi-frequency bioelectrical impedance method before the race and after each stage in order to show changes in body composition.

          Results: Between pre race and after the first day, a statistically significant decrease of body mass (- 2.4 kg, p=0.014), body fat (- 5 kg, p=0.0078) and percent body fat (- 6.4 %, p=0.0078) occurred. In contrast, at the same time, a statistically significant increase of protein mass (+ 0.7 kg, p=0.035), mineral mass (+ 0.2 kg, p=0.04), total body water (+ 1.8 l, p=0.042), intracellular water (+ 1.6 l, p=0.034) and lean body mass (+ 2.6 kg, p=0.023) was shown. After the first day until the finish, body fat (- 3kg, p>0.05) and percent body fat (- 3.9 %, p>0.05) showed a statistically significant decrease, whereas the other parameters showed no changes.

          Conclusions: Athletes at a multi-stage ultra-endurance triathlon over 10 times an Ironman triathlon within 10 days lost 3 kg of body fat whereas skeletal muscle mass, mineral mass and body water did not change.

          • anthropometry
          • bioelectrical impedance analysis
          • endurance performance
          • percent body fat

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