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G-35 Free Communication/Poster - Running Saturday, June 2, 2018, 7: 30 AM - 11: 00 AM Room: CC-Hall B

Association Between Race Time, Body Mass, and Total Body Water in Ultramarathon Runners

3158 Board #27 June 2 8

00 AM - 9

30 AM

Cousins, Julie M.; Betz, Heather H.

Author Information
Medicine & Science in Sports & Exercise: May 2018 - Volume 50 - Issue 5S - p 775
doi: 10.1249/01.mss.0000538550.81916.3c
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Acute bouts of prolonged endurance exercise have been found to significantly decrease body mass. Some researchers suggest that a decrease in body mass may improve performance in weight-bearing exercise. Yet, other researchers suggest the decrease in body mass may impair exercise performance.

PURPOSE: The purpose of this study was to investigate the association between race time with changes in body mass (BM) and total body water (TBW) in ultramarathon runners.

METHOD: 10 ultramarathon runners (age = 36.4 (10.0) years, race time = 5.7 (1.5) hours) were assessed with the InBody 270 bioelectrical impedance analysis (BIA) before and after a 50k race. The InBody 270 BIA measured BM, skeletal muscle mass (SMM), fat mass (FM), and total body water (TBW). Race time was recorded as the runners crossed the finish line. Statistical analysis was performed using paired t-test, multiple linear regression, and Pearson product-moment correlations. Significance was set to p< 0.05.

RESULTS: BM significantly decreased by 2.15 (1.44) kg (p=0.001) while TBW showed a nonsignificant increase of 0.93 (1.79) kg (p=0.134). SMM decreased by 1.1 (1.24) kg (p=0.023) and FM decreased by 3.67 (1.83) kg (p<0.001). There was a positive correlation between race time and age (r =0.676, p=0.032). Multiple linear regression suggested that change in BM and TBW predicted 10% of the variance in race time.

CONCLUSIONS: Change in BM and TBW were not significantly associated with race time. BM was significantly decreased following the ultramarathon race. A limitation of the study is the small sample size. Therefore, additional research is needed to examine the relationship between performance and changes in BM in a larger sample size of ultramarathon runners.

© 2018 American College of Sports Medicine