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Dana LeBar ACF Abstract FY11

"Hydration strategies and change in body mass during pre-season two-a-days in female college soccer players"

Conference Name: American College of Sports Medicine Annual Meeting (Midwest Chapter)

Introduction: Fluid loss and dehydration can negatively impact physical performance, skill execution, and at severe levels cause physical harm. Sports camps held during summer months are associated with significant body mass and fluid loss through sweating, which therefore places increased emphasis on maintaining adequate hydration. Purpose: To monitor hydration strategies and changes in body mass as a result of pre-season two-a-days in college soccer players. Methods: 16 female DII soccer players (19 ± 1 yrs; 1.68 ± 0.03 m; 64.8 ± 7.5 kg) were monitored during a morning and subsequent afternoon training session. The previous night participants ingested a telemetry sensor for recording of core body temperature (Tint). Prior to each session, body mass (BM) and dry uniform weight were determined, Tint was measured, and the environmental conditions were taken. Participants were free to drink water and a commercially available 6% carbohydrate sports drink ad libitum. During each break between drills, Tint, heart rate (HR), and environmental conditions were recorded. At the end of each session, Tint, HR, BM, wet uniform weight and volume of both water and sports drink consumed were determined. Statistical analyses were performed on select within and between-session variables using paired t-tests. Results: There were no differences in both Tint and HR between sessions. More total fluid was consumed in the morning compared to the afternoon (1.11 ± 0.39 L vs. 0.81 ± 0.35 L; p<0.05), but there were no differences in type of fluid consumed, either between or within sessions. Net BM loss was greater in the morning compared to the afternoon (1.7 ± 0.4 kg vs. 1.4 ± 0.2 kg, p<0.05), which equated to 2.7 ± 0.6% and 2.2 ± 0.4% net BM loss, respectively. Overall, there was a net BM loss of 2.8 ± 0.5 kg (4.4 ± 0.7%) across the whole day. Conclusion: The hydration strategies used failed to offset marked session-specific and daily body mass losses encountered during soccer pre-season two-a-days performed in a moderate heat stress environment. Further research is needed to elucidate the impact on acute hydration status and of consecutive two-a-days on chronic hydration status in college soccer players.

Matthew T. Wittbrodt1, Dana K. Lebar2, & Ross A. Sherman2

1Western Michigan University, Kalamazoo, Michigan; 2Grand Valley State University, Allendale, Michigan