Athletic Performance and Weight Changes during the “Marathon of Sands” in Athletes Well-trained in Endurance

Abstract

The purpose of this study is to examine the effects of the “Marathon of Sands” (MS), a 7–day, self-sufficient-diet, multi-stage running race across a section of the Moroccan desert, on body weight and plasma volume variation (PVV) and the relationship of these factors to performance in athletes who are well-trained in endurance. Sixteen MS runners agreed to participate in this study. Weight and body composition were measured and venous blood samples were taken before the first stage (D₀), after the third stage (D₃) and at the end of the MS (after the sixth stage: D₆). Haematocrit and haemoglobin were used to calculate PVV at (D₀, D₃, and D6). No significant plasma volume decrease was observed throughout the race. Significant decreases in total body weight (BW), fat-free mass (FFM) and fat mass (FM) were observed in D₃ and D₆ (−4.3%, −3.5%, −0.8%; and −6.1%, −5%, −1.1%, respectively, for BW, FFM and FM at D₃ and D₆). This study clearly shows that, despite extreme conditions, the MS did not lead to a significant PV decrease in athletes well-trained in endurance. This study also supports the hypothesis that significant body weight loss may not systematically affect performances during long duration multiple-stage races.

Key words

haematocrit - hydration - fluid loss - long duration race

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