soccer players, body weight, body water, body fat, fat free mass, repeated measurement

The objective of this study is to evaluate changes in the resulting values of body composition parameters as a consequence of water intake using two devices routinely applied in the field. The research was performed in a group of 33 soccer players (mean age 17.28?0.45 years). The measurements were taken using Tanita 418 - MA (frequency 50 kHz) and Nutriguard-M (frequency 100 kHz). The Tanita device showed statistically significant differences after the intake of 500 ml in parameters BH (+0.42 kg), BF (+0.39 kg, + 0.53%) and TBW (-0.38 %). As for the Nutriguard device, statistically significant differences were found in parameters TBW (+0.77 kg), ICW (+0.83 kg), FFM (+1.05 kg), BCM (+0.79 kg) and ECM/BCM (-0.01). Also, the water intake had no effect on the accuracy of measurement of both devices. The measurements of the SE values before and after the water intake did not differ.