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Kubo, J., T. Kukidome, S. Katsuyoshi, M. Saito, Y. Nakashima , O. Yanagisawa, and T. Homma. Med Sci Sports Exerc 38 (5 (Supp)):S51, 2006.
Background: Most wrestlers are required to loose weight in order to qualify for participation in championship competition. In order to attain peak performance, it is desirable to maximize fat loss while preserving muscle mass. However, many wrestlers are obliged to engage in weight loss regimens that do not purely produce a loss in fat mass. PURPOSE : Using an authentic championship setting, the purpose of this study was to investigate the effect of weight loss methods utilized by Japanese collegiate wrestlers on body segment size and thigh composition. METHODS : The subjects included 12 male Japanese university wrestlers competing in a collegiate wrestling championship. Measurements were performed at the following time points: 1) one month in advance, 2) one week in advance, 3) immediately prior to weight-in, 4) the day of the championship, and 5) one week after the championship. Body weight and fat percentage were measured by bioelectric impedance analysis equipment (InBody, Biospace, KOR). Thigh composition was measured by calculating the muscle and subcutaneous fat size (cross-sectional area) at the longitudinal midpoint of the thigh by magnetic resonance imaging (Magnetom Symphony, Siemens , Germany ). Volume and cross-sectional are of the whole body and each segment were measured by 3-dimensional whole body scan (BLS, Hamamatsu Photonics , Japan ). RESULTS : Weight loss averaged 5.6 kg at time point 1). Although body weight at time points 3) and 4) were significantly lower than at other time points (p<0.01), there were no significant differences among body weight at time points 1), 2), and 5). Body fat percentage at time points 3) and 4) were significantly lower as compared to 1) (p<0.01). Body fat percentage at time point 5) was significantly higher as compared to 3) and 4) (p<0.01). The volume of the trunk, upper, and lower body segments were significantly different except for time points 1) and 2). Muscle cross-sectional area of the thigh at 3) was significant smaller compared to other time points (p<0.01). Subcutaneous fat size at 2) was significantly smaller compared to 3) (p<0.01). CONCLUSION : Results indicate that male Japanese university wrestlers loose approximately 5kg within one week prior to weigh-in. Since muscle size only significantly decreased immediately prior to weigh in (time point 3), we speculate that dehydration was the primary source of weight loss and reduction in muscle size. In addition, since subcutaneous fat immediately prior to weigh in was smaller than that measured one week prior, it is conceivable that fat loss has little effect on the reduction in body weight.
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