Body Mass Change and Ultraendurance Performance
- 1 June 2012
- journal article
- Published by Ovid Technologies (Wolters Kluwer Health) in Journal of Strength & Conditioning Research
- Vol. 26 (6), 1505-1516
- https://doi.org/10.1519/jsc.0b013e318231a7b5
Abstract
Rüst, CA, Knechtle, B, Knechtle, P, Wirth, A, and Rosemann, T. Body mass change and ultraendurance performance: a decrease in body mass is associated with an increased running speed in male 100-km ultramarathoners. J Strength Cond Res 26(6): 1505–1516, 2012—We investigated, in 50 recreational male ultrarunners, the changes in body mass, selected hematological and urine parameters, and fluid intake during a 100-km ultramarathon. The athletes lost (mean and SD) 2.6 (1.8) % in body mass (p < 0.0001). Running speed was significantly and negatively related to the change in body mass (p < 0.05). Serum sodium concentration ([Na+]) and the concentration of aldosterone increased with increasing loss in body mass (p < 0.05). Urine-specific gravity increased (p < 0.0001). The change in body mass was significantly and negatively related to postrace serum [Na+] (p < 0.05). Fluid intake was significantly and positively related to both running speed (r = 0.33, p = 0.0182) and the change in body mass (r = 0.44, p = 0.0014) and significantly and negatively to both postrace serum [Na+] (r = −0.42, p = 0.0022) and the change in serum [Na+] (r = −0.38, p = 0.0072). This field study showed that recreational, male, 100-km ultramarathoners dehydrated as evidenced by the decrease in >2 % body mass and the increase in urine-specific gravity. Race performance, however, was not impaired because of the loss in body mass. In contrast, faster athletes lost more body mass compared with slower athletes while also drinking more. The concept that a loss of >2% in body mass leads to dehydration and consequently impairs endurance performance must be questioned for ultraendurance athletes competing in the field. For practical applications, a loss in body mass during a 100-km ultramarathon was associated with a faster running speed.Keywords
This publication has 57 references indexed in Scilit:
- No Fluid Overload in Male Ultra-Runners During a 100 km Ultra-RunResearch in Sports Medicine, 2010
- A Triple Iron Triathlon Leads to a Decrease in Total Body Mass But Not to DehydrationResearch Quarterly for Exercise and Sport, 2010
- Influence of Hydration on Physiological Function and Performance During Trail Running in the HeatJournal of Athletic Training, 2010
- No Change of Body Mass, Fat Mass, and Skeletal Muscle Mass in Ultraendurance Swimmers After 12 Hours of SwimmingResearch Quarterly for Exercise and Sport, 2009
- Athletic Performance and Serial Weight Changes During 12- and 24-Hour Ultra-MarathonsClinical Journal of Sport Medicine, 2008
- Errors in the estimation of hydration status from changes in body massJournal of Sports Sciences, 2007
- Core temperature and hydration status during an Ironman triathlon * Commentary * CommentaryBritish Journal of Sports Medicine, 2006
- Online-Publication of the German Food Composition Table “Souci–Fachmann–Kraut“ on the InternetJournal of Food Composition and Analysis, 2002
- Prediction of fat and fat-free mass in male athletes using dual X-ray absorptiometry as the reference methodJournal of Sports Sciences, 2000
- Effect of water ingestion on endurance capacity during prolonged runningJournal of Sports Sciences, 1996