3, 4, 5 and 6 It must be emphasized, however, that there is a need for methods used in body composition determination that are practical, fast, MK-2206 concentration and easy to perform, with the possibility of being applicable to several working conditions, including in population-based studies in the field. Among these methods, bioelectrical impedance analysis (BIA) is highlighted, as it has all these characteristics at a relatively low cost, in addition to its portability and noninvasiveness.4, 5, 7, 8 and 9 The use of previous preparations (protocols) for

standardization of variables that affect body hydration is a recommendation to perform BIA.9, 10 and 11 However, its use may be restricted by lack of adherence or difficulty to follow these requirements by the adolescent. Given the importance of accurately determining body composition and the broad use of BIA, this study aimed to determine the predictive capacity of four different devices in the evaluation of adolescents with and without a protocol. This was an epidemiological, cross-sectional study, with a population of 215 adolescents of both genders, aged between 10 years to 14 years, 11 months, selected by simple random sampling from all public and private schools in the age range of interest, located NVP-BGJ398 mw in urban and rural areas of the city of Viçosa, state of Minas Gerais, Brazil. The following inclusion criteria were used: interest in participating in the study; absence of

prosthetics and/or pacemakers; absence of chronic Ureohydrolase diseases or use of continuous medication that could interfere with body hydration; and adherence to the recommended protocol to undergo BIA. Sample selection was based on the total number of adolescents in the city at the age of interest in 2010.12 The sample was calculated using

EpiInfo software, release 6.04 for cross-sectional studies, considering a total population of 5,754 individuals, the expected frequency of excess body fat of 17.5%, 13 and variability of 5%, totaling 214 individuals, with a confidence level of 95%. The sample draw was conducted among all who met the inclusion criteria and returned the signed informed consent, respecting the proportionality of the number of students that each school had in each age group. When the adolescent did not want to participate or abandoned the study, a new draw was made to replace him/her. The project was approved by the Ethics Committee on Human Research of Universidade Federal de Viçosa (protocol. N. 0140/2010); adolescents and their parents signed the consent form, prepared in accordance with standards established by 196/96 Resolution of the National Health Council. Weight was measured on a digital scale with a maximum capacity of 150 kg and a sensitivity of 50 g, whereas height was measured using a portable stadiometer with an extension of 2.13 m and 0.1 cm resolution. Measurements were made in duplicate, allowing the use of the mean values between the two measurements. In cases where the difference exceeded 0.