DXA assessment

Accurate assessment of body composition is an important issue among athletes. Different methodologies generate controversial results, leading to a deep uncertainty on individual exercise prescriptions. Thus, this study aims to identify the differences between field methods, such as bioelectrical impedance (BIA) and skinfold assessment, with a clinical method, highly accurate, dual-energy X-ray absorptiometry (DXA), among elite young football players. Thirty-eight male football players with a mean (sd) age of 16.7 (0.87) years, involved in the Portuguese national competition of U16 (n = 13) and U19 (n = 25), were evaluated and objective measures of body composition, muscle strength and football skills were collected by trained specialists. Body composition was assessed using BIA (Tanita BC-418, Tanita Corp., Tokyo, Japan), in agreement with all the evaluation premises. Additionally, all athletes were evaluated using the clinical method DXA (Hologic Inc., Waltham, MA, USA). Among the U19 athletes, three skinfold sites (SKF) were assessed: chest, abdomin and thigh. The Spearman correlation coefficients and the mean difference between methods were calculated. The agreement between both methods was analyzed using Bland-Altman plots. Among the evaluated athletes, lower mean values of body fat % were found using BIA as a method of body composition assessment compared with DXA (12.05 vs. 15.58 for U16; 11.97 vs. 14.16 for U19). Despite the moderate correlation between methods (r = 0.33) to estimate the percentage of total fat, the median of the difference (DXA vs. BIA) was relevant in clinical terms, with 2.90% and 1.47% for U16 and U19 athletes, respectively. Stronger correlations were found between the sum of the SKF and DXA fat estimation (r = 0.68). The Bland-Altman plots showed a clear underestimation in the evaluations using the BIA, namely among athletes with better body composition profiles (8%?12% of fat). Using BIA, an underestimation of body fat assessment was observed among 94.5% of the athletes with less than 12% body fat mass. Among the evaluated athletes, fat mass was underestimated at a median value of 2.21% using BIA in comparison with DXA. The sum of the SKF showed a stronger correlation with the reference method (DXA) (r = 0.68) than BIA.D915-7373-ED16 | Cesar LeaoN/

Perfil microbiológico da carne de frangos abatidos artesanalmente e na indústria, comercializados na grande Recife-PE

Considerando o elevado consumo da carne de frango no contexto nacional e mais especificamente na cidade do Recife, onde o abate clandestino ainda é intenso, objetivou-se delinear o perfil microbiológico da carne de frango disponível no mercado, comparando-se os produtos advindos de abatedouro industrial e artesanal e verificar se os produtos atendiam às especificações dos padrões recomendados pela legislação. Determinou-se o Número Mais Provável (NMP) de coliformes totais e termotolerantes, bem como realizou-se a pesquisa de Salmonella spp. e Aeromonas spp., além da contagem de bactérias aeróbias mesófilas, psicrófilas e Staphylococcus spp.. Foram analisadas 24 amostras, sendo que 12 advindas do processamento de frigoríficos industriais, resfriadas e comercializadas. As outras 12 amostras foram provenientes de abatedouro artesanal e comercializadas sem refrigeração. Nos resultados obtidos, a contagem de Staphylococcus spp., a determinação do NMP de coliformes totais e termotolerantes apresentaram valores acima dos permitidos nas carcaças artesanais, enquanto que, as pesquisas de Salmonella spp. e Aeromonas spp. não apresentaram diferença significativa. Nas carcaças artesanais o número de bactérias mesófilas foi 2,6 vezes maior que nas industriais, enquanto que no número de psicrófilas/pisicotróficas não houve diferença significativa entre as amostras. Algumas amostras não estão dentro dos padrões recomendados pela legislação

Anthropometric profile of soccer players as a determinant of position specificity and methodological issues of body composition estimation

The aim of the present study was (a) to describe the anthropometric profile of a large group of soccer players based on different age groups and their playing positions on the field, and (b) to examine the variations of body composition among adult soccer players using diverse equations based on skinfold thickness. A total of 618 Greek soccer players who were grouped by age (i.e.,12?14, 14?16, 16?18, and 18?37 years) and playing position (i.e., goalkeeper, defender, midfielder, and forward) were evaluated for weight, height, and skinfolds. The Pa?r?zkov? formula was used to estimate the percentage of body fat. Furthermore, for players who were 18 years or older the Reilly and Evans formulas was used to estimate the percentage of body fat. Independent of the age, in this large sample, goalkeepers presented higher values for weight, height and the percentage of body fat estimation as compared with other field positions. An anthropometric pattern was observed in each tactical position, namely, across a specific age of increasing maturation process (14?16 years). With the Pa?r?zkov? formula, we found a mean (SD) range of variation in the percentage of body fat estimation between 4.87 ? 1.46 and 5.51 ? 1.46 as compared with the Evans formula. The same pattern of differences was found when the Reilly equation was considered. In conclusion, we observed a position specificity of anthropometric characteristics across different age categories. Additionally, the same data supported different validated equations which resulted in large differences in the final outcome estimations.D915-7373-ED16 | Cesar LeaoN/

Relationship between power condition, agility, and speed performance among young roller hockey elite players

Purpose. The study was intended to describe the correlations between speed performance (11 m, 22 m, and 33 m) and agility test in skates with determinants of muscular power (squat jump, countermovement jump) in young Portuguese roller hockey athletes involved in a regional selection. Methods. A cross-sectional study was conducted among 10 male roller hockey players with mean (? SD) age of 14.20 (0.57) years, involved in the Portuguese national competition of under-15, making part of the final Oporto district selection of players to participate in inter-regional selections competition. Their mean (? SD) weight, height, body mass index, and sum of the skinfolds were 58.62 (8.78) kg, 165.72 (8.45) cm, 21.26 (1.52) kg/m2, 51.80 (14.91) mm, respectively. Furthermore, it strength was measured with squat jump and countermovement jump; sprinting time at 11 m, 22 m, and 33 m was determined, as well as time in an agility t-test, conducted in roller skating. Spearman correlation coefficients were calculated to test the associations. Results. Significant inverse correlations between vertical jumps, a practical method of power training monitoring, and linear velocity in skating (countermovement jump vs. speed, ?0.78) were found. Despite the increasing complexity of the agility test, a moderate inverse correlation with strength was observed, too (?0.48). Conclusions. Lower limbs explosive strength turned out a strong predictor of skating linear speed and agility among young roller hockey players, providing a simple evaluation tool of important determinants of performance.D915-7373-ED16 | Cesar LeaoN/

effects of the pre-season period

Study aim: To assess changes in physical fitness of amateur soccer players after a pre-season training period and baseline fitness dependencies. Material and methods: Twenty-one amateur soccer players were assessed during the pre-season. The following physical vari ables were assessed before and after a two-month pre-season training period: (i) cardiorespiratory fitness, (ii) strength and power, and (iii) change of direction (COD). Results: Significant decreases were found for countermovement jump (CMJ) (p < 0.001; d = 1.161), drop jump (DJ) (p = 0.014; d = 0.958), and horizontal jump (HJ) (p = 0.042; d = 0.640), while no significant changes were found for the overall variables from the beginning to the end of pre-season. Fit players revealed significant decreases for CMJ (p = 0.002; d = ?2.495), DJ (p = 0.004; d = ?1.760), HJ (p = 0.028; d = ?1.005), COD deficit (p = 0.034; d = 1.013), and maximal aerobic speed (MAS) (p = 0.026; d = ?4.053). No significant changes were found for unfit players. Conclusions: Amateur soccer coaches should consider assessing physical qualities at the beginning of pre-season and use the free-of-charge monitoring tools such as session-rate of perceived exertion (s-RPE) during the training process.D915-7373-ED16 | Cesar LeaoN/

Observation of the thermal Casimir force

Quantum theory predicts the existence of the Casimir force between macroscopic bodies, due to the zero-point energy of electromagnetic field modes around them. This quantum fluctuation-induced force has been experimentally observed for metallic and semiconducting bodies, although the measurements to date have been unable to clearly settle the question of the correct low-frequency form of the dielectric constant dispersion (the Drude model or the plasma model) to be used for calculating the Casimir forces. At finite temperature a thermal Casimir force, due to thermal, rather than quantum, fluctuations of the electromagnetic field, has been theoretically predicted long ago. Here we report the experimental observation of the thermal Casimir force between two gold plates. We measured the attractive force between a flat and a spherical plate for separations between 0.7 $\mu$m and 7 $\mu$m. An electrostatic force caused by potential patches on the plates' surfaces is included in the analysis. The experimental results are in excellent agreement (reduced $\chi^2$ of 1.04) with the Casimir force calculated using the Drude model, including the T=300 K thermal force, which dominates over the quantum fluctuation-induced force at separations greater than 3 $\mu$m. The plasma model result is excluded in the measured separation range.Comment: 6 page

The effect of early infection with Echinostoma paraensei on the interaction of Schistosoma mansoni with Biomphalaria glabrata and Biomphalaria tenagophila

Infection caused by the trematode Echinostoma paraensei has been shown to interfere in the natural resistance to infection by Schistosoma mansoni. Biomphalaria glabrata is susceptible to infection, while Taim isolate Biomphalaria tenagophila is resistant to infection by S. mansoni. These two snail species were assessed for infection with E. paraensei two days after exposure to S. mansoni miracidia. The number of B. tenagophila and B. glabrata infected with E. paraensei was lower in co-infected group, suggesting an antagonistic relationship. B. glabrata showed an increase in its susceptibility to S. mansoni, whereas B. tenagophila maintained its refractoriness to S. mansoni infection. Weekly comparisons made between the E. paraensei cercariae released from B. tenagophila and B. glabrata mono-infected snails revealed no quantitative differences. In contrast, S. mansoni cercariae released were higher in the B. glabrata co-infected group. Mortality rates were significantly greater in both species pertaining to co-infected group and unexpected mortalities were also observed in B. tenagophila exposed only to S. mansoni miracidia. Our study revealed that the B. tenagophila Taim isolate is susceptible to E. paraensei infection, although infection did not alter its resistance to S. mansoni infection