The relative body fat and anthropometric prediction of body density of South Australian females aged 17-35 years

One hundred and thirty-five females were tested in order to: produce some normative percentage body fat (% BF) data on an Australian sample which represented a cross-section of physical activity patterns, cross-validate existing multiple regression equations which predict body density (BD) from anthropometric measurements, and if necessary develop population specific equations. Measurements were taken of 10 girths, 3 widths and 7 skinfolds. Body density was measured by underwater weighing with the residual volume (RV) being determined by helium dilution. The Siri equation was then used to convert BD to % BF. The % BF scores had an overall mean of 23.4 (range 10.8-49.2). The very active group (n = 45) had a significantly lower (p less than 0.05) relative body fat (X = 20.6% BF) than either the active (n = 45; 23.5% BF) or sedentary groups (n = 45; 26.2% BF). Previously published equations were found to have limited applicability to Australian subjects. A stepwise multiple regression was therefore used to develop the following equation (R = 0.893): BD(g X cm-3) = 1.16957-0.06447 (log10 sigma triceps, subscapular, supraspinale, front thigh, abdominal and calf skinfolds in mm)-0.00081 (gluteal girth in cm) + 0.0017 (forearm girth in cm) + 0.00606 (biepicondylar humerus breadth in cm). Only those predictors which resulted in a statistically significant increase in r (p less than or equal to 0.05) were included. The standard error of estimate of 0.00568 g X cm-3 was equivalent to 2.6% BF at the mean.     

Relative body fat and anthropometric prediction of body density of female athletes

Ninety-one percent (n = 182) of the female members of South Australian representative squads in 14 sports volunteered to act as subjects. Twenty-seven percent of them had represented Australia. The underwater weighing method together with the measurement of residual volume (RV) by helium dilution were used to determine body density (BD); the percent body fat (% BF) was then computed according to Siri. A stepwise multiple regression analysis yielded a correlation coefficient (R) of 0.863 between the criterion (BD) and the best weighted sum of predictors (anthropometric variables): BD (g X cm-3) = 1.14075-0.04959 (log10 sigma triceps, subscapular, supraspinale and calf skinfolds in mm) + 0.00044 (age in decimal years)-0.000612 (waist girth in cm) + 0.000284 (height in cm)-0.000505 (gluteal girth in cm) + 0.000331 (breast girth in cm). Only those predictors which resulted in a statistically significant increase in R (p less than or equal to 0.05) were included. The standard error of estimate of 0.00597 g X cm-3 was equivalent to 2.7% BF at the mean. This equation was shown to be largely population specific. There was a range of 7.6-35.8% of BF and the overall mean 18.5% was significantly lower (p less than 0.001) than that of 23.4% obtained on a moderately active reference sample of similar age (n = 135). If group sizes of only one or two are regarded as too small for meaningful comparison, then the lowest mean of 13.5% was achieved by the long-distance runners (n = 14). The highest averages were registered by the heavyweight rowers (24.2%; n = 7) and soccer players (22.0%; n = 11). The overall average for games players (n = 107) was 19.4%.     

Validation of five simple models estimating body fat in white postmenopausal women: use in clinical practice and research

The aim of this study was to validate noninvasive models, retrieved from the literature, estimating body fat in white women. The cohort used for the validation consisted of 277 postmenopausal women, and the reference method was dual-energy X-ray absorptiometry (DXA). Five models were retrieved containing anthropometric measurements such as bicep and tricep skinfolds, waist circumference (WC), height, and body weight. Models including only BMI were found to be less biased and more valid than others including skinfolds and circumferences. The model by Visser et al., estimating body density (BD = 0.0226 × sex - 0.0022 × BMI + 1.0605) with the subsequent use of Brozek's (and not Siri's) equation to estimate body fat percentage (%BF), was found to be more valid than the other models for this cohort. In conclusion, it seems that Visser's et al. model, including only BMI, with Brozek's equation, is a fast, noninvasive, and valid method to assess body composition in white postmenopausal women in clinical practice and research.     

Contributions of body fat and effort in the 5K run: age and body weight handicap

The 5K handicap (5KH), designed to eliminate the body weight (BW) and age biases inherent in the 5K run time (RT), yields an adjusted RT (RTadj) that can be compared between runners of different BW and age. As hypothesized in a validation study, however, not all BW bias may be removed, because of the influences of body fatness (BF) and effort (run speed; essentially the inverse as measured by rating of perceived exertion (RPE)). This study's purpose was to determine the effects of BF and RPE on BW bias in the 5KH. For 99 male runners in a regional 5K race (age = 43.9 +/- 12.1 years; BW = 83.4 +/- 12.9 kg), BF was determined via sum of three skinfolds just before the race. RPE, on the 20-point Borg scale, was used to assess overall race effort on race completion. Multiple regression analysis was used to develop a new adjusted RT (NRTadj, the RTadj corrected for BF and RPE), which was computed for each runner and then correlated with BW to determine bias. Indicative of slight bias, BW was correlated with RTadj (r = 0.220, p = 0.029). Both BF (p = 0.00002) and RPE (p = 0.0005) were significant, independent predictors of RTadj. NRTadj was not significantly correlated with BW (r = 0.051, p = 0.61), but BF explained 90%, and RPE explained only 6%, of the remaining BW bias evidenced in the 5KH. The previous finding that the 5KH does not remove all BW bias is apparently accounted for by BF and not RPE. Because no handicap should be awarded for higher BF, this finding suggests that the 5KH, for men, appropriately adjusts for the age and BW vs. RT biases previously noted.     

Reliability of air displacement plethysmography

The purpose of this study was to examine the reliability of an air displacement plethysmography device (BOD POD) over trials performed on 3 different days. Subjects consisted of 24 healthy adults (8 men, 16 women), ages 18-38 years, with body weights 46.8-93.6 kg, body mass indexes of 19.1-30.1 kg x m(-2), and percentage body fats (BF) of 7.9-43.1%. Two estimates of BF were performed on 3 days. Paired t-tests revealed no significant within-day differences in body volume (BV), thoracic gas volume (V(TG)), body density (BD), and BF. Correlations between the two V(TG) measures on a day were r = 0.86 for day 1, r = 0.93 for day 2, and r = 0.96 for day 3. BF estimates within a day had high correlations of r = 0.98. Significant differences were found between days for measures of BV, V(TG), BD, and BF. These results indicate a high reliability for within-day estimates of BF and significant differences in between-day estimates of BF using air displacement plethysmography. Reliability of BF may be increased by requiring subjects to practice the procedure for V(TG) measurement.     

Regional adiposity, body composition and central body fat distribution of 10-16 years old Bengalee boys of Nimta, North 24 Parganas, West Bengal, India

A cross-sectional study of 502 Bengalee boys aged 10-16 years of Nimta, North 24 Parganas, West Bengal, India, was undertaken to study regional adiposity, body composition and central body fat distribution. The subjects were classified into seven age groups: 10-10.9 years (n = 74), 11-11.9 (n = 53), 12-12.9 (n = 87), 13-13.9 (n = 116), 14-14.9 (n = 58), 15-15.9 (n = 57), 16-16.9 (n = 57). In general, there was a significant linear increasing trend from 10 to 16 years for all the anthropometric variables. There was a net increase of 30.5 cm and 22.8 kg in mean height and weight, respectively, between 10 and 16 years of age. Mean BMI increased by 3.7 kg/m2 during the same period. Among circumferences, the largest increase was in hip followed by chest while the smallest increase was in mid upper arm, between 10 and 16 years of age. Subscapular skinfold showed the largest increase followed by abdomen and suprailiac skinfolds, while the increase was least in forearm skinfold. Significant linear increasing trend was observed for all the body composition measures. The largest increase in percent of body fat (PBF) was observed between ages 10 and 11 years while mean fat mass (FM), fat free mass (FFM) and fat mass index (FMI) increased the most between 14 to 15 years. However, an overall decreasing trend was observed, in mean waist-to-hip ratio (WHR) from 10 to 16 years. Boys aged 10 years had the highest mean WHR while those aged 15 years had the lowest mean WHR. There was an increase in mean WHR among 16 years old boys.     

Body adiposity index assess body fat with high accuracy in nondialyzed chronic kidney disease patients

Objective:

High body fat (BF) is an alarming condition that also affects nondialyzed chronic kidney disease (CKD) patients. Distinct methods are used to evaluate BF; however, in CKD population it remains unclear which one is more reliable showing high accuracy. Dual‐energy X‐ray absorptiometry (DXA), used as reference method to estimate adiposity, is expensive and time consuming to be applied in clinical settings. Recently, a new body adiposity index (BAI), that estimates BF from easily accessible measures, was validated in the general population. The aim of this study was to evaluate which simple and practical method, routinely used to estimate BF, shows the highest accuracy compared with DXA, in nondialyzed CKD patients.

Design and Methods:

In this cross‐sectional study BF was estimated by DXA, bioelectrical impedance analysis (BIA), anthropometry (ANTHRO), and BAI. Serum leptin levels were determined.

Results:

Studied patients (n = 134) were 55% males, 54% overweight/obese, and 64.9 ± 12.5 years old, with estimated glomerular filtration rate (eGFR) = 29.0 ± 12.7 ml/min. The correlation coefficient was higher between DXA vs. ANTHRO (r = 0.76) and BAI (r = 0.61) than with BIA (r = 0.57), after adjusting for gender, age, and eGFR (P < 0.0001). Therefore, the Lin's concordance correlation coefficient and Bland–Altman plots were performed to measure the accuracy (C_b) between DXA with both ANTHRO and BAI. A higher accuracy (C_b = 0.82) and lower mean difference (?3.4%) was observed for BAI than for ANTHRO (C_b = 0.61; ?8.4%). Leptin levels correlated (P < 0.0001) with DXA (r = 0.56) and BAI (r = 0.59).

Conclusions:

These findings suggest that BAI estimates BF with high accuracy in nondialyzed CKD patients and may be helpful in the treatment of this population with increased BF.

     

Physical fitness and anthropometrical profile of the Brazilian male judo team

The present study had as objectives (1) to compare the morphological and functional characteristics of the male judo players of the Brazilian Team A (n=7) with the judo players of Teams B and C (reserves; n=15), and (2) to verify the association between the variables measured. Thus, 22 athletes from the seven Olympic weight categories were submitted to: a body composition evaluation (body mass, height, ten skinfolds, eight circumferences, three bone diameters and percent body fat estimation); the Special Judo Fitness Test (SJFT); maximal strength tests (one repetition-maximum, 1 RM, in bench press, row, and squat); and the Cooper test. One-way analysis of covariance was used to compare the groups. The relationships between variables were determined by the Pearson coefficient correlation. The significance level was fixed at 5%. No significant difference was found in any variable between them. The main significant correlations observed were between the following variables: VO2max and number of throws in the SJFT (r=0.79); percent body fat and estimated VO2max (r=-0.83) and number of throws in the SJFT (r=-0.70); chest circumference and bench press 1 RM (r=0.90) and in the row (r=0.80); and thigh circumference and squat 1 RM (r=0.86). However, there was no significant correlation between circumferences and 1 RM/kg of body mass. According to these results the main conclusions are: (1) the physical variables measured do not discriminate performance when analysis is directed to the best athletes; (2) a higher percent body fat is negatively correlated with performance in activities with body mass locomotion (Cooper test and the SJFT); (3) judo players with higher aerobic power performed better in high-intensity intermittent exercise; (4) judo players with bigger circumferences present bigger absolute maximal strength.     

Validity and Reliability of A-Mode Ultrasound for Body Composition Assessment of NCAA Division I Athletes

This study evaluated the validity and reliability of the BodyMetrix™ BX2000 A-mode ultrasound for estimating percent body fat (%BF) in athletes by comparing it to skinfolds and the BOD POD. Forty-five (22 males, 23 females) National Collegiate Athletic Association (NCAA) Division-I athletes volunteered for this study. Subjects were measured once in the BOD POD then twice by two technicians for skinfolds and ultrasound. A one-way repeated-measures ANOVA revealed significant differences between body composition methods (F = 13.24, p < 0.01, η² = 0.24). This difference was further explained by a sex-specific effect such that the mean difference between ultrasound and BOD POD was large for females (~ 5% BF) but small for males (~ 1.5% BF). Linear regression using the %BF estimate from ultrasound to predict %BF from BOD POD resulted in an R² = 0.849, SEE = 2.6% BF and a TE = 4.4% BF. The inter-rater intraclass correlation (ICC) for skinfold was 0.966 with a large 95% confidence interval (CI) of 0.328 to 0.991. The inter-rater ICC for ultrasound was 0.987 with a much smaller 95% CI of 0.976 to 0.993. Both skinfolds and ultrasound had test-retest ICCs ≥ 0.996. The BX2000 ultrasound device had excellent test-retest reliability, and its inter-rater reliability was superior to the skinfold method. The validity of this method is questionable, particularly for female athletes. However, due to its excellent reliability, coaches and trainers should consider this portable and easy to use A-mode ultrasound to assess body composition changes in athletes.     

Activity Profiles and Physiological Responses of Representative Tag Football Players in Relation to Playing Position and Physical Fitness

This study determined the physical fitness, match-activity profiles and physiological responses of representative tag football players and examined the relationship between physical fitness and the match-activity profile. Microtechnology devices and heart rate (HR) chest straps were used to determine the match-activity profiles of sixteen tag football players for five matches during the 2014 Australian National Championships. The relationships between lower body muscular power, straight line running speed and Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) and the match-activity profile were examined using Pearson’s correlation coefficients. Outside players had greater lower body muscular power (ES = 0.98) and straight line running speed (ES = 1.03–1.18) than inside players, and also covered greater very high-speed running (VHSR) distance/min (ES = 0.67) and reached higher peak running speeds (ES = 0.95) during matches. Inside and outside players performed a similar number of repeated high-intensity effort (RHIE) bouts and reported similar mean and maximum efforts per RHIE bout. However, there were differences between playing positions for mean and maximal RHIE effort durations (ES = 0.69–1.15) and mean RHIE bout recovery (ES = 0.56). Inside and outside players also reported small to moderate differences (ES = 0.43–0.80) for times spent in each HR zone. There were a number of moderate to very large correlations between physical fitness measures and match-activity profile variables. This study found lower body muscular power, straight line running speed and Yo-Yo IR2 to be related to the match-activities of representative tag football players, although differences between inside and outside players suggest that athlete testing and training practices should be modified for different playing positions.     

Impact of peroxisome proliferator-activated receptors gamma and delta on adiposity in toddlers and preschoolers in the GENESIS Study

Peroxisome proliferator-activated receptor gamma (PPAR gamma) and peroxisome proliferator-activated receptor delta (PPAR delta) are promising candidate genes for obesity. Associations between adiposity-related phenotypes and genetic variation in PPAR gamma (Pro12Ala and C1431T), as well as PPAR delta (T+294C) were assessed in 2,102 Greek children aged 1-6 years, as part of a large-scale epidemiological study (Growth, Exercise and Nutrition Epidemiological Study In preSchoolers). In girls aged 3-4 years, the Ala12 allele was associated with higher mid-upper arm (P = 0.010) and hip (P = 0.005) circumferences, as well as subscapular (P = 0.008) and total skinfolds (P = 0.011) that explained 2.0, 3.7, 2.1, and 1.9% of the phenotypic variance, respectively, while the T1431 allele was associated with higher mean values for waist circumference (P = 0.018) and suprailiac skinfold (P = 0.017), genotype accounting for 1.6% of the variance in both phenotypes. No significant effects of PPAR delta T+294C polymorphism or the interaction of the PPAR delta and PPAR gamma variants on adiposity-related phenotypes were observed in any age group or gender. Haplotype-based analysis including both PPAR gamma polymorphisms revealed that in girls aged 3-4 years, the Ala-T haplotype was associated with higher waist (P = 0.014) and hip (P = 0.007) circumferences compared to the common Pro-C haplotype. The PPAR gamma Pro12Ala and C1431T polymorphisms are associated with increased adiposity during early childhood in a gender- and age-specific manner and independently of the PPAR delta T+294C polymorphism.     

Blood lead level and nutritional status indicators in preadolescent Polish schoolchildren

BackgroundEnvironmental pollutions with heavy metals may have toxic effects on human health and development. One of the most detrimental is lead exposure, which may disturb neurodevelopment and linear growth in children. However, data on the effect of lead exposure on nutritional and weight status in children are limited, thus this study aimed to assess the effect of blood lead (Pb) level on nutritional and weight status in preadolescent schoolchildren from the industrialized, mining region in southwestern Poland.MethodsOur study sample involved N = 709 schoolchildren (402 boys and 307 girls) in the preadolescent developmental period (7–11 years of age for boys and 7–10 years of age for girls). Anthropometric measurements were used to assess nutritional and weight status: body mass index (BMI), mid-upper arm circumference (MUAC) and skinfolds thicknesses (triceps, subscapular, abdominal and the sum of skinfolds). Blood Pb level was evaluated and divided into two groups: above (>3.7 μg/dL) and below median value (≤3.7 μg/dL).ResultsAnalysis of covariance (with children’s age controlled as a covariate) revealed that children with blood Pb level above median value had significantly lower values of BMI, MUAC and all skinfolds (at least p < 0.01). However, this effect was significant only in boys, whereas in girls differences were non-significant (p > 0.05). The highest effect size of blood Pb level was noted for skinfolds thicknesses (partial η²: 0.015 for the sum of skinfolds).ConclusionsNutritional status in children with higher blood Pb level is significantly impaired in preadolescent boys, who appear to be more sensitive to this environmental factor. Our findings indicate a particular need for nutritional and environmental interventions among preadolescent children in regions with higher lead exposure.     

Kinetics of bicarbonate transport in human red blood cell membranes at body temperature

We studied unidirectional [14C]HCO3- efflux from human resealed red cell ghosts with 1 mM acetazolamide under self-exchange conditions at pH = pH(i = o) 7.4-9.0 and 0-38 degrees C by means of the Millipore- Swinnex and continuous flow tube filtering techniques. 14CO2 loss from cells to efflux medium and further to the atmosphere was insignificant. [14C]HCO3- efflux was determined at pH 7.8, 38 degrees C under symmetric variation of the HCO3- concentrations (C(i = o)), and asymmetric conditions: C(i) varied, C(o) constant, or C(o) varied, C(i) constant. MM-fit, Jeff = Jmaxeff x C x (C + K1/2)-1, used to describe the concentration dependence of Jeff,o when only C(o) varied, yields at C(i) = 50 mM: K1/2o = 3.8 mMJ, Jmaxeff.o = 20 nmol cm-2 s-1; at C(i) = 165 mM: K1/2o = 10 mM, Jmaxeff.o = 32 nmol cm-2 s-1. When C(i) varied, noncompetitive self inhibition by HCO3- binding (inhibitor constant K1) to an intracellular site was included (MS-fit). Under conditions of (a) symmetry: C(i = o) = 9-600 mM, K1/2s = 173 mM, K1 = 172 mM, and Jmaxeff,s = 120 nmol cm-2 s-1, (b) asymmetry: C(o) = 50 mM, K1/2i = 116 mM, K1 = 136 mM, and Jmaxeff,i = 92 nmol cm-2 s-1. All flux parameters accord with the ping-pong model for anion exchange. The data for C(i) < 200 mM also fit well to the MM equation, but K1/2 and Jmaxeff are different from the MS-fit and are inconsistent with the ping-pong model. Thus, self-inhibition (MS-fit) must be included even at low concentrations. As at 0 degree C, the system is asymmetric: 8-10 times more unloaded transport sites face inward than outward when C(i = o). Jeff,s was not mono-exponentially dependent on temperature at 0-38 degrees C, indicating that the transmembrane anion transport is controlled by several rate constants with different temperature dependencies. Jeff,s was not significantly affected by increasing pH(i = o) from 7.4 to 7.8, but it decreased by 50% when pH was raised to 9.0.     

Thermal excitations of a bilipid membrane.

Propagating modes of vibration of a bilipid membrane have been detected with light beating spectroscopy. The dependence of omega on q is consistent with a model of a fluid film of surface tension sigma = 2.5 +/- 0.5 dyn cm-1 surrounded by a medium with rho = 1 g cm-3 and eta = 1.01 X 10(-2) P.     

Directional asymmetry of body dimensions among white adolescents

Asymmetry of paired dimensions has been recognized as a methodological problem in anthropometry and more recently as an indicator of environmental stress. This study seeks to determine the extent of directional asymmetry for some of the measurements commonly made in anthropometry. Upper arm circumference, biepicondylar breadth, triceps and subscapular skinfolds, bicondylar breadth of the femur, and calf circumference were measured on right and left sides among 135 white adolescents from suburban Philadelphia. Handedness (right or nonright) was subject-assessed. Body composition was estimated through underwater weighing. Asymmetry was evaluated using a paired t test. Arm measurements are significantly asymmetric in favor of the right side; subscapular skinfolds and leg measurements are not significantly asymmetric. Among the sample of right-handed subjects (n = 116), upper arm circumference and biepicondylar breadth were significantly larger on the right side, and, among the males of this subsample, triceps was as well. The nonright-handed subjects (n = 19) did not show statistically significant asymmetry. Asymmetry was negatively but weakly related to body composition. These results are consistent with an explanation in terms of preferred use of one side of the body and consequent muscle hypertrophy, but an adequate test of this explanation requires hypothesis testing in larger samples of nonright-handed subjects.     

Long-term training adaptations in elite male volleyball players

Several investigations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite-level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear. The purpose of this investigation was to examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players. Fourteen national team volleyball players (age, 23.0 ± 4.1 years; height, 1.98 ± 0.07 m; weight, 91.7 ± 7.9 kg) began and completed this study. Participants had all played international matches (representing Australia) before the examination time period and continued to do so during the international season. Anthropometry (stature, mass, and sum of 7 skinfolds), vertical jump measures (countermovement vertical jump; depth jump from 0.35 m, DJ; spike jump, SPJ, all including arm swing), and lower-body power (jump squat at body mass, and jump squat + 50% body weight, JS50) measures were tested before and at the conclusion of the investigation period. Significant (p < 0.05) improvements were observed in sum of 7 skinfolds, DJ, SPJ, and JS50 performance, with large magnitude changes (d > 0.70) in the sum of 7 skinfolds reduction, SPJ, and leg extensor power. This study has demonstrated that elite male volleyball players can improve leanness and power, which contribute to improvements in vertical jump.     

High Molecular Weight Poly(butylene succinate-co-butylene furandicarboxylate) Copolyesters: From Catalyzed Polycondensation Reaction to Thermomechanical Properties

Novel potentially biobased aliphatic-aromatic copolyesters poly(butylene succinate-co-butylene furandicarboxylate) (PBSFs) in full composition range were successfully synthesized from 2,5-furandicarboxylic acid (FA), succinic acid (SA), and 1,4-butanediol (BDO) via an esterification and polycondensation process using tetrabutyl titanate (TBT) or TBT/La(acac)(3) as catalyst. The copolyesters were characterized by size exclusion chromatography (SEC), Fourier transform infrared (FTIR), (1)H NMR, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and their tensile properties were also evaluated. The weight average molecular weight (M(w)) ranges from 39?000 to 89?000 g/mol. The copolyesters are random copolymers whose composition is well controlled by the feed ratio of the diacid monomers. PBSFs have excellent thermal stability. The glass transition temperature (T(g)) increases continuously with ?(BF) and agrees well with the Fox equation. The crystallizability and T(m) decrease with increasing butylene furandicarboxylate (BF) unit content (?(BF)) from 0 to 40 mol %, but rise again at ?(BF) of 50-100 mol %. Consequently, the tensile modulus and strength decrease, and the elongation at break increases with ?(BF) in the range of 0-40 mol %. At higher ?(BF), the modulus and strength increase and the ultimate elongation decreases. Thus, depending on ?(BF), the structure and properties of PBSFs can be tuned ranging from crystalline polymers possessing good tensile modulus (360-1800 MPa) and strength (20-35 MPa) to nearly amorphous polymer of low T(g) and high elongation (～600%), and therefore they may find applications in thermoplastics as well as elastomers or impact modifiers.     

Anthropometric and physiological characteristics of young soccer players according to their playing positions: relevance for competition success

Lago-Pe?as, C, Casais, L, Dellal, A, Rey, E, and Domínguez, E. Anthropometric and physiological characteristics of young soccer players according to their playing positions: relevance for competition success. J Strength Cond Res 25(12): 3358-3367, 2011-The aim of this study was to establish the anthropometric and physiological profiles of young soccer players according to their playing position and to determine their relevance for competition success. Three hundred and twenty-one young male soccer players participated in the study. Players, age 15.63 (±1.82) years, range 12-19 years, were classified into the following groups: Goalkeepers (n = 35), Central Defenders (n = 53), External Defenders (n = 54), Central Midfielders (n = 61), External Midfielders (n = 46), and Forwards (n = 72). The anthropometric variables of participants (height, weight, body mass index, 6 skinfolds, 4 diameters, and 3 perimeters) were measured. Also, their somatotype and body composition (weights and percentages of fat, bone, and muscle) were calculated. Participants performed the 20-m progressive run test to estimate their relative VO(2)max, a sprint test (30 m flat), and 3 jump tests (squat jump, countermovement jump, and Abalakov test). External Midfielders were the leanest and shortest. In contrast, Central Defenders and Goalkeepers were found to be the tallest and heaviest players. They also had the largest fat skinfolds. In general, the results show that heavier and taller young soccer players performed better in vertical jumps and 30-m sprint, whereas leaner players performed better in the 20-m progressive run test. Players were classified into 2 groups according to the final ranking of their teams at the end of the season. Players from successful teams performed slightly better than players from unsuccessful teams in the physiological test, but these differences were not statistically significant. Moreover, players from successful teams were found to be leaner and more muscular than their unsuccessful counterparts.     

Equation for estimating total body water by bioelectrical impedance measurements in Japanese subjects]

This article reports a study in which the equation for total body water (TBW) estimated from deuterium (2H2O)-dilution method and bioelectrical impedance measurement (BIM) is described. Subjects were 60 healthy males aged 30 +/- 18.3 yr (18-74) and 31 healthy females aged 37 +/- 17.5 yr (19-70). Total body water determined by the analysis of the dilution of orally ingested deuterium oxide (1g2H2O, 99.75 atom % excess/kg body weight) in urine. Bioelectrical impedance was measured for each subjects in a supine position using an electrical impedance analyzer (500 microA, 50kHz, T-1988K, Toyo Physical Inc.) with a four electrodes (Y-250, Nihon Kohden). The mean values of total body water and the impedance in males and females subjects were 34.1 +/- 4.27 l and 25.7 +/- 2.42 l, 567 +/- 28.5 omega and 562 +/- 32.5 omega, respectively. Height squared divided by resistance (Ht2/R) correlated well with TBW as measured by 2H2 O, r = 0.530 (p less than 0.001) in males and r = 0.782 (p less than 0.001) in females. The best-fitting regression equation to predict TBW comprised Ht2/R(X1) and body weight (X2) (R = 0.915, SEE = 1.70 l in males and R = 0.834, SEE = 1.28 l in females). Equations were provided with BIM instrument for the prediction of TBW: for males TBW, l = 0.1983X1 + 0.4004X2 - 0.7938 and for females TBW, l = 0.3536X1 + 0.1269X2 + 3.3417. These results suggest that bioelectrical impedance measurement is a useful measure of total body water in Japanese subjects.     

Excretion of trimethylselenonium ion in human urine

A method to permit isolation and measurement of trimethylselenonium ion [TMSe, (CH3)3Se+] from 1 liter of human urine was developed. The method was based on precipitation of TMSe with ammonium reineckate, preseparation with anion-exchange resin, and final thermal decomposition and collection of the product in HNO3. It was tested for recovery and separation from other selenium moieties present in urine using both in vivo-labeled rat urine and human urine spiked with unlabeled TMSe. Recoveries from the former were in the range 76.8-87.0% (mean +/- SD: 81.8 +/- 3.7%, n = 5), while for the latter they were in the range 72.0-93.0% (mean +/- SD for three occasions (%): 80.9 +/- 5.5, 81.4 +/- 7.8, and 78.9 +/- 1.0). The reliability of the method was tested against an HPLC procedure using in vivo-labeled rat's urine. The mean (+/- SD) percentage of urine radioactivity appearing as TMSe was 36.0 +/- 5.7% for the present and 36.2 +/- 6.6% for the HPLC method. The mean of deviations, as percentage of the HPLC method, was -0.03 +/- 8.8%. The linear regression equation for the two methods was y = -0.805 + 1.029x (r2 = 0.81). Excretion of TMSe was measured in urine samples from several persons (range: 0.18-0.37 micrograms Se/liter; mean +/- SD: 0.26 +/- 0.07, n = 9). One subject consumed three separate doses of unlabeled selenite on alternate days (Day 1, 197 micrograms Se; Day 3, 395; and Day 5, 592). For the first 24 h of each period, TMSe excretions (micrograms Se/24 h) were 0.24, 0.53, and 0.97, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)