Prediction of fat-free mass from body surface area in young basketball players.

BACKGROUND: Fat Free Mass (FFM) is an important and essential indicator in various sports populations, since greater muscle and bone mass generates greater strength, endurance and speed in athletes. OBJECTIVE: The purpose of the study was to validate Body Surface Area (BSA) as an anthropometric indicator to estimate FFM in young basketball players. METHODS: A descriptive cross-sectional study was carried out in 105 male basketball players of the Brazilian Basketball Confederation of Sao Paulo (Campinas), Brazil. The age range was 11 to 15 years. Weight and height were evaluated. BSA, body mass index (BMI) and maturity status (MS) were calculated. Total body scanning was performed by dual X-ray absorptiometry (DXA). The components were extracted: Fat mass (FM), Fat free mass (FFM), percentage of fat mass (%FM) and bone mass (BM). The data were analyzed using the correlation coefficient of concordance (CCC) in terms of precision and accuracy. RESULTS: Three regression equations were generated: equation 1 had age and body weight as predictors [FFM= -30.059+(2.926*age)+(0.625*Weight)] (R2 = 92%, precision = 0.96 and accuracy = 0.99), equation 2 used age and BSA [FFM=-45.719+(1.934*age)+(39.388*BSA)] (R2 = 94%, precision = 0.97 and accuracy = 0.99) and equation 3 was based on APHV and BSA [FFM=-15.284+(1.765*APHV)+(37.610*(BSA)] (R2 = 94%, precision = 0.96 and accuracy = 0.99). CONCLUSIONS: The results suggest the use of anthropometric equation using decimal age and BSA to estimate FFM in young basketball players. This new method developed can be used to design, evaluate and control training programs and monitor the weight status of athletes.

Positive association of lean mass and negative association of protein intake on bone mass and bone geometry of adolescent soccer players.

OBJECTIVE: The aim of this study was to evaluate the association of food consumption and body composition on bone parameters in adolescent soccer players. METHODS: There were 148 male soccer players 12 to 18 y who participated in the study. Body composition was assessed by dual energy x-ray absorptiometry, comprising bone mineral density (BMD) and bone mineral content (BMC) of total body without head (TBLH), lumbar spine (L1-L4), and right femoral neck (RFN). The bone geometry variables measured were femoral strength index (FSI), buckling ratio (BR), section modulus (Z), cross-sectional moment of inertia (CSMI), and cross-sectional area (CSA). Food intake was analyzed using the 24-h food recall. Somatic maturation was estimated by the peak height velocity equation. For the statistical analysis, the stepwise multiple linear regression was used, with P < 0.05. RESULTS: Regarding food consumption, there was a high protein intake and low calcium intake. Lean mass was a predictor of BMC of TBLH (R2 = 0.524), L1-L4 (R2 = 0.492), and RFN (R2 = 0.405); BMD of L1-L4 (R2 = 0.407) and RFN (R2 = 0.27); Z (R2 = 0.683), CSMI (R2 = 0.630), and CSA (R2 = 0.640). There was a negative correlation between protein intake with bone mass and bone geometry parameters. CONCLUSION: In adolescent soccer players, lean mass was a predictor of bone parameters, and high protein intake was negatively associated with bone mass and geometry.

Phase Angle is Determined by Body Composition and Cardiorespiratory Fitness in Adolescents.

The phase angle is used to evaluate nutritional status and is an indicator of cellular health. Cardiorespiratory fitness and body composition are strong indicators of health during adolescence. We aimed to evaluate if body composition and cardiorespiratory fitness have an association with phase angle among adolescents. 203 girls and 220 boys (12.8±1.3 years) were evaluated. Peak height velocity, percentage fat mass, fat-free mass, cardiorespiratory fitness, and phase angle measurements were collected. Linear regression adjusted by peak height velocity was used to verify if predictor variables were associated with phase angle among adolescents. Phase angle showed correlation with fat-free mass (girls: r=0.42 and boys: r=0.37); with percent fat mass (girls: r=0.23); and with cardiorespiratory fitness (boys: r=0.19). Linear regression showed that percentage fat mass (in girls) and cardiorespiratory fitness (in boys) had an effect of 11 and 17% in phase angle, respectively, while fat-free mass had an effect of 22 and 26% in phase angle for girls and boys, respectively. Changes in phase angle seem to be more associated with the percentage fat mass in girls, cardiorespiratory fitness in boys, and fat-free mass in both when controlled by peak height velocity.

Brazilian pediatric reference data for quantitative ultrasound of phalanges according to gender, age, height and weight.

AIMS: To establish normative data for phalangeal quantitative ultrasound (QUS) measures in Brazilian students. METHODS: The sample was composed of 6870 students (3688 females and 3182 males), aged 6 to 17 years. The bone status parameter, Amplitude Dependent Speed of Sound (AD-SoS) was assessed by QUS of the phalanges using DBM Sonic BP (IGEA, Carpi, Italy) equipment. Skin color was obtained by self-evaluation. The LMS method was used to derive smoothed percentiles reference charts for AD-SoS according to sex, age, height and weight and to generate the L, M, and S parameters. RESULTS: Girls showed higher AD-SoS values than boys in the age groups 7-16 (p<0.001). There were no differences on AD-SoS Z-scores according to skin color. In both sexes, the obese group showed lower values of AD-SoS Z-scores compared with subjects classified as thin or normal weight. Age (r2 = 0.48) and height (r2 = 0.35) were independent predictors of AD-SoS in females and males, respectively. CONCLUSION: AD-SoS values in Brazilian children and adolescents were influenced by sex, age and weight status, but not by skin color. Our normative data could be used for monitoring AD-SoS in children or adolescents aged 6-17 years.

Cross-sectional study of the association of body composition and physical fitness with bone status in children and adolescents from 11 to 16 years old.

BACKGROUND: The aim of the study was to verify the association between body composition and physical fitness with bone status in children and adolescents. METHODS: A cross-sectional study was conducted with 300 healthy students (148 boys, 152 girls). Weight, height, fat and fat-free mass, and percentage of body fat (%BF) were evaluated, as were physical fitness (abdominal exercise, flexibility, and horizontal jump tests) and maximum oxygen consumption. Bone parameters (amplitude-dependent speed of sound; AD-SoS) and the Ultrasound Bone Profile Index (UBPI) were evaluated using DBM Sonic BP ultrasonography. RESULTS: In the study group, girls had higher bone parameter values than boys. A univariate analysis assessed in a stepwise multiple regression model was conducted. It showed that for boys, the %BF and height were significant independent variables for AD-SoS and UBPI, but the horizontal jump test only for AD-SoS (adjusted r2 = 0.274; p < 0.001), and pubertal maturation only for UBPI (adjusted r2 = 0.295; p < 0.001). For girls, age and %BF were identified as significant independent variables for AD-SoS and UBPI (adjusted r2 = 0.093; p < 0.001) but height only for AD-SoS (adjusted r2 = 0.408; p < 0.001). CONCLUSIONS: Variables related to growth (age, height, and pubertal maturation) are independent positive predictors for the bone parameters in both boys and girls. %BF is an independent negative predictor. For boys, the horizontal jump test was an independent positive predictor for AD-SoS, indicating that physical fitness related to the neuromotor system can influence the amount of bone present.

The distances covered by basketball referees in a match increase throughout the competition phases, with no change in physiological demand.

BACKGROUND: It is crucial to know the demands on basketball referees, in different match periods (MPs) and phases of competition, for planning referee training and subsequent successful refereeing. OBJECTIVE: To measure and evaluate the distance covered by referees in a match by measuring the number of interruptions, percentage of heart rate (%HR), and blood lactate concentration ([lac]) in different phases of competition and in different MPs. METHOD: We studied the qualifying (QP), semifinal (SP), and final (FP) phases of a total of 12 matches (four matches in each phase) of the 2009-2010 Brazilian Basketball League. Distance covered, number of match interruptions, and referees' %HR and [lac] were analyzed. We compared the results between competition phases and between MPs (1st MP, 2nd MP, 3rd MP, and 4th MP). RESULTS: Regarding the distances covered, we observed significant differences (P < 0.05) in the 1st, 2nd, and 3rd MPs between the FP and the other two phases (SP and QP) throughout the match, between each phase; in the 4th MP, a significant difference was found when comparing the QP and the other two phases. Comparing the periods within each phase, we found that a greater distance was covered in the 4th MP in relation to the 3rd MP during the FP. No significant differences were found among the remaining variables. CONCLUSION: The distances covered by referees in a basketball match increase throughout competition phases. This information is essential for planning of training and for the subsequent success of a referee.