Juliano Henrique Borges

Minimum Time to Achieve the Steady State and Optimum Abbreviated Period to Estimate the Resting Energy Expenditure by Indirect Calorimetry in Healthy Young Adults

BACKGROUND The optimum abbreviated period for measurement by indirect calorimetry (IC) to estimate the resting energy expenditure (REE), including the acclimation period, in healthy individuals has not been established. This study aimed to determine the acclimation time required to achieve the REE steady state during a 30-minute IC measurement and to define the optimum abbreviated measurement period in the steady state to estimate the REE in healthy young adults. METHODS Thirty-nine volunteers (27 men and 12 women; age, 18-31 years) were recruited. The REE was obtained by IC over 30 minutes. Friedmans test was used to compare the coefficient of variation (CV%) among all 5-minute intervals (REE5). To compare the REE values obtained during the first REE5 interval in the steady state with the REE average values of the subsequent measurements, Student paired t test, linear regression, and Bland-Altman test were used. RESULTS The CV% of the first REE5 (mean ± standard deviation: 19.9% ± 13.2%) was significantly higher (P < .0001) than that of all other REE5 (second REE5: 7.4% ± 3.8%; third: 7.8% ± 5.2%; fourth: 7.1% ± 3.9%; fifth: 8.0% ± 5.7%; sixth: 8.0% ± 4.5%). No significant difference was found between the second REE5 and the REE average values of the last 20 minutes. The second REE5 explained 90% of the REE average of the last 20 minutes, with the 95% limits of agreement by the Bland-Altman test ranging from -142.92 to 150.44 kcal/d. CONCLUSION Ten minutes can be used as an abbreviated alternative for IC measurements in healthy young adults, and values of the first 5-minute interval should be discarded.

Validity of Bioelectrical Impedance Analysis to Estimation Fat-Free Mass in the Army Cadets

Background: Bioelectrical Impedance Analysis (BIA) is a fast, practical, non-invasive, and frequently used method for fat-free mass (FFM) estimation. The aims of this study were to validate predictive equations of BIA to FFM estimation in Army cadets and to develop and validate a specific BIA equation for this population. Methods: A total of 396 males, Brazilian Army cadets, aged 17–24 years were included. The study used eight published predictive BIA equations, a specific equation in FFM estimation, and dual-energy X-ray absorptiometry (DXA) as a reference method. Student’s t-test (for paired sample), linear regression analysis, and Bland–Altman method were used to test the validity of the BIA equations. Results: Predictive BIA equations showed significant differences in FFM compared to DXA (p < 0.05) and large limits of agreement by Bland–Altman. Predictive BIA equations explained 68% to 88% of FFM variance. Specific BIA equations showed no significant differences in FFM, compared to DXA values. Conclusion: Published BIA predictive equations showed poor accuracy in this sample. The specific BIA equations, developed in this study, demonstrated validity for this sample, although should be used with caution in samples with a large range of FFM.

Methods for data analysis of resting energy expenditure measured using indirect calorimetry

OBJECTIVES The aim of this study was to test the accuracy of different methods of resting energy expenditure (REE) data analysis using indirect calorimetry (IC) during traditional (30 min) and abbreviated (10 min) protocols. METHODS Fifteen women and 15 men (21-34 y of age) completed two consecutive 30-min IC measurements. Body composition was measured using dual-energy x-ray absorptiometry. The reference method for REE analysis was 5 min in steady state (SS) during 30 min (first 5 min discarded). REE measurements were randomized to define a reference or testing method. An interval method was defined using 25, 20, and 15 min (with first 5, 10, and 15 min discarded, respectively), during 30 min, and 5 min (first 5 min discarded) during 10-min intervals. The SS method was defined using 5 min in SS (first 5 min discarded) during 30 min, 5, 4, and 3 min in SS during 10-min (first 5 min discarded) intervals. RESULTS Interval methods during 30 min and SS and interval methods during 10 min demonstrated large bias with significantly high REEs compared to the reference method (78.8-109.0 kcal/d, all P < 0.001). Testing methods demonstrated large upper limits of agreement between 225.2 and 322.8 kcal/d. No mean differences (P > 0.05), small bias (14.3 kcal/d), and narrow limits of agreement (-125.8 to 154.4 kcal/d) were observed between 5-min SS during 30 min and the reference method. CONCLUSIONS All interval methods and SS methods during 10 min overestimated REE. We recommend using 5-min SS during 30 min. The measurement may be repeated until all participants achieve SS.

Accuracy of Bioelectrical Impedance Analysis in Estimated Longitudinal Fat-Free Mass Changes in Male Army Cadets

Introduction Bioelectrical impedance analysis (BIA) is a practical and rapid method for making a longitudinal analysis of changes in body composition. However, most BIA validation studies have been performed in a clinical population and only at one moment, or point in time (cross-sectional study). The aim of this study is to investigate the accuracy of predictive equations based on BIA with regard to the changes in fat-free mass (FFM) in Brazilian male army cadets after 7 mo of military training. The values used were determined using dual-energy X-ray absorptiometry (DXA) as a reference method. Materials and Methods The study included 310 male Brazilian Army cadets (aged 17-24 yr). FFM was measured using eight general predictive BIA equations, with one equation specifically applied to this population sample, and the values were compared with results obtained using DXA. The students t-test, adjusted coefficient of determination (R2), standard error of estimation (SEE), Lins approach, and the Bland-Altman test were used to determine the accuracy of the predictive BIA equations used to estimate FFM in this population and between the two moments (pre- and post-moment). Results The FFM measured using the nine predictive BIA equations, and determined using DXA at the post-moment, showed a significant increase when compared with the pre-moment (p < 0.05). All nine predictive BIA equations were able to detect FFM changes in the army cadets between the two moments in a very similar way to the reference method (DXA). However, only the one BIA equation specific to this population showed no significant differences in the FFM estimation between DXA at pre- and post-moment of military routine. All predictive BIA equations showed large limits of agreement using the Bland-Altman approach. Conclusion The eight general predictive BIA equations used in this study were not found to be valid for analyzing the FFM changes in the Brazilian male army cadets, after a period of approximately 7 mo of military training. Although the BIA equation specific to this population is dependent on the amount of FFM, it appears to be a good alternative to DXA for assessing FFM in Brazilian male army cadets.

Programa de treinamento influencia a relação entre os indicadores de desempenho funcional e neuromusculares durante a temporada em jovens futebolistas

a Universidade Estadual de Campinas, Faculdade de Educação Física, Programa de Pós-Graduação em Educação Física, Campinas, SP, Brazil b Universidade Estadual de Campinas, Faculdade de Educação Física, Departamento de Estudos da Atividade Física Adaptada, Campinas, SP, Brazil c Confederação Brasileira de Atletismo, São Paulo, SP, Brazil d Desportivo Brasil Participações LTDA, Porto Feliz, SP, Brazil e Universidade Estadual de Campinas, Faculdade de Ciências Médicas, Programa de Pós-Graduação em Saúde da Criança e do Adolescente, Campinas, SP, Brazil f Universidade Estadual de Campinas, Faculdade de Educação Física, Departamento de Ciências do Esporte, Campinas, SP, Brazil