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Reljic D.,University of Heidelberg | Reljic D.,Olympic Training Center Rhein Neckar | Hassler E.,University of Heidelberg | Jost J.,Olympic Training Center Rhein Neckar | Friedmann-Bette B.,University of Heidelberg
Journal of Athletic Training | Year: 2013

Context: Dehydration is assumed to be a major adverse effect associated with rapid loss of body mass for competing in a lower weight class in combat sports. However, the effects of such weight cutting on body fluid balance in a real-life setting are unknown. Objective: To examine the effects of 5% or greater loss of body mass within a few days before competition on body water, blood volume, and plasma volume in elite amateur boxers. Design: Case-control study. Setting: Sports medicine laboratory. Patients or Other Participants: Seventeen male boxers (age = 19.2 ± 2.9 years, height = 175.1 ± 7.0 cm, mass = 65.6 ± 9.2 kg) were assigned to the weight-loss group (WLG; n=10) or the control group (CON; n = 7). Intervention(s): The WLG reduced body mass by restricting fluid and food and inducing excessive sweat loss by adhering to individual methods. The CON participated in their usual precompetition training. Main Outcome Measure(s): During an ordinary training period (t-1), 2 days before competition (t-2), and 1 week after competition (t-3), we performed bioelectrical impedance measurements; calculated total body water, intracellular water, and extracellular water; and estimated total hemoglobin mass (tHbmass), blood volume, and plasma volume by the COrebreathing method. Results: In the WLG, the loss of body mass (5.6% ± 1.7%) led to decreases in total body water (6.0% ± 0.9%), extracellular water (12.4% ± 7.6%), tHbmass (5.3% ± 3.8%), blood volume (7.6% ± 2.1%; P <.001), and plasma volume (8.6% ± 3.9%). The intracellular water did not change (P >.05). At t-3, total body water, extracellular water, and plasma volume had returned to near baseline values, but tHbmass and blood volume still were less than baseline values (P <.05). In CON, we found no changes (P >.05). Conclusions: In a real-life setting, the loss of approximately 6% body mass within 5 days induced hypohydration, which became evident by the decreases in body water and plasma volume. The reduction in tHbmass was a surprising observation that needs further investigation© 2013 by the National Athletic Trainers' Association, Inc. Source

Reljic D.,University of Heidelberg | Reljic D.,Olympic Training Center Rhein Neckar | Jost J.,Olympic Training Center Rhein Neckar | Dickau K.,Olympic Training Center Rhein Neckar | And 3 more authors.
Journal of Sports Sciences | Year: 2015

Abstract: Dietary intake, vitamin status and oxidative stress were evaluated in 17 elite male boxers. Ten of them frequently reduced body weight rapidly before competitions (Weight Loss Group) and 7 did not practice rapid weight loss (Control Group). Food record checklists, blood samples for determination of vitamin status and plasma glutathione levels were obtained during a week of weight maintenance, a pre-competition week and a post-competition week. The average dietary intakes in both groups were 33 ± 8 kcal·kg−1, 3.7 ± 1.1 g·kg−1 carbohydrates, 1.5 ± 0.4 g·kg−1 protein, 1.2 ± 0.4 g·kg−1 fat and 2.2 ± 1.0 L water per day (excluding pre-competition week in Weight Loss Group). Energy (18 ± 7 kcal·kg−1), carbohydrate (2.2 ± 0.8 g·kg−1), protein (0.8 ± 0.4 g·kg−1), fat (0.6 ± 0.3 g·kg−1) and water (1.6 ± 0.6 L) consumption (P-values <0.001) and intakes of most vitamins (P-values < 0.05) were significantly reduced during the pre-competition week in the Weight Loss Group. In both groups, the intakes of vitamins A, E and folate were below recommended values throughout the three periods; however, blood vitamin and plasma glutathione levels did not change significantly. Our findings indicate a low-caloric and low-carbohydrate diet in elite boxers, regardless of participating in rapid weight loss or not. Apparently, the pre-competitional malnutitrition in the Weight Loss Group did not induce alterations in the vitamin and glutathione status. ©2014,Taylor & Francis. Source

Reljic D.,University of Heidelberg | Reljic D.,Olympic Training Center Rhein Neckar | Feist J.,University of Heidelberg | Jost J.,Olympic Training Center Rhein Neckar | And 2 more authors.
Scandinavian Journal of Medicine and Science in Sports | Year: 2016

Rapid body mass loss (RBML) before competition was found to decrease hemoglobin mass (Hbmass) in elite boxers. This study aimed to investigate the underlying mechanisms of this observation. Fourteen well-trained combat athletes who reduced body mass before competitions (weight loss group, WLG) and 14 combat athletes who did not practice RBML (control group, CON) were tested during an ordinary training period (t-1), 1-2 days before an official competition (after 5-7 days RBML in WLG, t-2), and after a post-competition period (t-3). In WLG, body mass (-5.5%, range: 2.9-6.8 kg) and Hbmass (-4.1%) were significantly (P<0.001) reduced after RBML and were still decreased by 1.6% (P<0.05) and 2.6% (P<0.001) at t-3 compared with t-1. After RBML, erythropoietin, reticulocytes, haptoglobin, triiodothyronine (FT3), and free androgen index (FAI) were decreased compared with t-1 and t-3. An increase occurred in ferritin and bilirubin. Peak treadmill-running performance and VO2peak did not change significantly, but performance at 4-mmol lactate threshold was higher after RBML (P<0.05). In CON, no significant changes were found in any parameter. Apparently, the significant decrease in Hbmass after RBML in combat athletes was caused by impaired erythropoiesis and increased hemolysis without significant impact on aerobic performance capacity. © 2016 John Wiley & Sons A/S. Source

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