Related Experiment Video
Updated: Jul 14, 2026
A Chronic High-Intensity Interval Training and Diet-Induced Obesity Model to Maximize Exercise Effort and Induce Physiologic Changes in Rats
Published on: April 28, 2023
Effect of a multistage ultra-endurance triathlon on body composition: World Challenge Deca Iron Triathlon 2006
B Knechtle1, O Salas Fraire, J L Andonie
1Gesundheitszentrum St Gallen, St Gallen, Switzerland. beat.knechtle@hispeed.ch
Objective:
To investigate the effect of a multistage ultra-endurance triathlon on body composition in ultra-triathletes.
Design:
Descriptive field study.
Setting:
The "World Challenge Deca Iron Triathlon 2006" in Monterrey, Mexico, in which every day for 10 consecutive days athletes had to perform the distance of one Ironman triathlon.
Subjects:
Eight male ultra-endurance athletes (mean (SD) age 40.6 (10.7) years, weight 76.4 (8.4) kg, height 175 (4) cm and body mass index (BMI) 24.7 (2.2) kg/m2).
Interventions:
None.
Main Outcome Measurements:
Determination of body mass, protein mass, body fat, per cent body fat, mineral mass, total body water, intracellular water, extracellular water and lean body mass with a direct segmental multifrequency bioelectrical impedance method before the race and after each stage in order to show changes in body composition.
Results:
A statistically significant decrease of body mass (-2.4 kg, p = 0.014), body fat (-5 kg, p = 0.0078) and per cent body fat (-6.4%, p = 0.0078) occurred at the end of the first day compared to values taken in the pre-race period. 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 litres, p = 0.042), intracellular water (+1.6 litres, p = 0.034) and lean body mass (+2.6 kg, p = 0.023) was shown. After the first day until the end of the challenge, body fat (-3 kg, p>0.05) and per cent body fat (-3.9%, p>0.05) showed a statistically significant decrease, whereas the other parameters showed no changes.
Conclusions:
Athletes taking part in a multistage ultra-endurance triathlon over 10 Ironman triathlon distances in 10 consecutive days lost 3 kg of body fat; skeletal muscle mass, mineral mass and body water were unchanged.
Related Concept Videos
01:27Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
01:20Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:24Muscle Recovery and Fatigue