Maturation level in adolescents: effects on body composition and physical activity changes

Background and aims: Longitudinal studies help move researchers closer to understanding determinants and mediators of maturation, physical activity (PA) and adiposity. The aim of this study was to longitudinally explore the influence of maturation on PA and adiposity changes in adolescents. Methods: Eighty healthy adolescents (42 girls and 38 boys) were followed over three academic years. A PA score was estimated using the Physical Activity Questionnaire (PAQ-A). Fat mass percentage (FMP) was assessed by anthropometric measurements. Sexual maturity was estimated by percentage of predicted adult stature and adolescents were classified into three changes groups: C0, change from on time to late maturation; C1, no change; C2, change from late/on time to on time/early maturation. A stepwise linear regression was conducted in order to estimate the predictors of PA and FMP changes. Results: An interaction between PA and maturation was statically significant (P<0.05). A non-significant trend was observed between three stages of change with a progressive reduction of FMP across the three stages of change in maturation level (C0 = 0.2752.70%; C1= -1.4901.10%; C2= -6.4172.57%; pairwise comparisons: C0 - C2 = 6.69%, P=0.081 and C1-C2 = 4.93%, P=0.080). Conclusions: Our results suggest that body composition changes observed during adolescence are not driven by changes in PA. PA alteration patterns were influenced by sex but not by maturation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Supported by the Spanish Ministry of Education, Culture and Sport (AP2010-0583); the Spanish Ministry of Economy and Competitiveness (DEP2011-30565

Rapidity gaps at HERA and the Tevatron from soft colour exchanges

Models based on soft colour exchanges to rearrange colour strings in the final state provide a general framework for both diffractive and non-diffractive events in ep and hadron-hadron collisions. We study two such models and find that they can reproduce rapidity gap data from both HERA and the Tevatron. We also discuss the influence of parton cascades and multiple interactions on the results.Comment: 4 pages, 4 EPS figures, presented at UK Phenomenology Workshop on Collider Physics, Durham. Uses iopart.cl

Reference values of total and regional skeletal muscle mass in children and adolescents

Introduction: The acquisition of skeletal muscle mass (SMM) during childhood and adolescence must be a main concern to ensure healthy growth and improved motor development. Moreover, peak SMM increment must happen during youth, which would determine adulthood health and performance. Although some indicators of SMM have been using for assessment of nutrition status since the seventies like upper arm circumference or arm areas there is insuffi cient SMM data throughout childhood and adolescence to establish references norms. The first aim of this study, therefore, was to analyze trends of fat free mass (FFM) and regional and total SMM. The second objective was to compare trends between SMM and FFM by age and gender. Method: Cross-sectional data of 1103 healthy volunteers were analyzed (13.3 ± 2.5 yrs, BMI=20.1 ± 3.4 kg/m2; 323 girls and 780 boys). They were recruited from local primary schools, high-schools and local sport clubs. Anthropometry in accordance with ISAK guidelines was used to measure: triceps, thigh and calf skinfolds, and arm, thigh and calf circumferences were assessed by a caliper and tape respectively. Regional muscle areas were calculated from the corrected limb circumferences. FFM was estimated by anthropometric-derived equation. Validated age-specifi c models were applied to obtain SMM based on anthropometric variables (Poortmans’ (0.000) while FFM showed 688.7 (P>0.000). Sex interaction was found. Conclusions: Our fi ndings show that there is a diff erence between boys and girls in the relationship between total SMM and age. Regional muscle areas from the upper limbs don’t develop in linear fashion with age in contrast to development in the lower extremity areas. These results suggest that upper and lower muscle areas growth is diff erent in terms of timing. Longitudinal studies are required to confirm these results.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Concurrent and Construct Validity of Methods to Estimate Fat-Free Mass in Children, Adolescents, and Young Adults

INTRODUCTION: Indirect methodologies are available to estimate fat-free mass (FFM) as a skeletal muscle mass surrogate in field settings at low cost. However, there is a lack of knowledge related with the FMM estimations variability introduced by the available methods and its correlations with performance constructs. The association between repeated measures of FFM by different methodologies and strength tests must provide a valuable construct validity analysis, which allows us to select the best method to assess the functional body composition. PURPOSE: To analyze validity and agreement between laboratory and field methods to estimate FFM in children, adolescents, and young adults, and their relationships with strength. METHODS: We studied a dataset of participants aged 6-21y (531 assessments, 287 boys). FFM was evaluated by isotope dilution method (REF), dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA) and anthropometry (ANT). Isometric strength was assessed by limb dynamometry and dynamic strength as sprinting and jumping. Concurrent validity was analyzed by differences between methods and concordance correlation coefficient (CCC), agreement by Bland-Altman analysis, and construct validity by individual associations. RESULTS: FFM from ANT had the lowest bias in girls (-2.33±4.41kg, P≤0.0001) and from BIA in boys (-1.79±4.51kg, P≤0.0001). The best CCC was found for FFM-BIA (girls, 0.764; boys, 0.926). The highest correlation with constructs was found for handgrip and FFM-BIA in girls (r=-0.743) and FFM-REF in boys (r=0.812; both P≤0.001). CONCLUSION: Our results showed BIA was the best method to estimate FFM. Nonetheless, there was not a single method which correlated the best with all strength constructs. The low coordinative requirement of isometric strength test could be one of the reasons to find a better correlation with FFM than explosive dynamic tests, and this leads us to speculate that isometric strength is more dependent of body composition than dynamic tests. These findings needed to be refuted with additional constructs

Efficacy of different recovery strategies in elite soccer players

Una correcta estrategia de recuperación (ER) tras la competición o el entrenamiento de alta intensidad en fútbol ayudará a no disminuir el rendimiento y a prevenir lesiones. El objetivo de este trabajo fue estudiar la eficacia de diferentes estrategias de recuperación combinadas en comparación con una simple, tras una sesión de entrenamiento específico de fútbol. Participaron 20 jugadores de fútbol de élite y se utilizaron cuatro estrategias de recuperación de forma aleatoria y contrabalanceada a lo largo de 4 semanas de entrenamiento. Se midió temperatura timpánica y las escalas subjetiva Total Quality Recovery (TQR) y Category Ratio Scale (CR10). Los resultados exponen que ninguna de las ER estudiadas muestra ser más eficaz que las demás. No obstante, la realización de protocolos de recuperación combinados llevados a cabo tras la sesión de entrenamiento de fútbol, tiende a una mayor eficacia respecto al protocolo que incluía únicamente estiramientosAfter a soccer match or high intensity training, suitable recovery will help not to decrease performance and to prevent injuries. The aim of this study was to test the effectiveness of different combined recovery strategies in comparison with a simple one, after a specific soccer training session. Twenty elite players participated in the study. A randomized crossover design was used to determine the effect of 4 post-training session recovery strategies. Tympanic temperature was measured, as well as Total Quality Recovery (TQR) and Category Ratio Scale (CR10) subjective scales. Results show that none of the recovery strategies proved more effective than others. However, the use of combined strategies tended to be more effective than a simple strategy after a high intensity training session in socce

TBW Assessment by Deuterium Dilution in Spanish Adolescents

Congreso para especialistas en Nutrición, Actividad Física y Composición CorporalINTRODUCTION: Total body water (TBW) assessment is a cornerstone in order to validate equations to estimate body composition components as fat mass and fat free mass. Deuterium dilution technique (D2DT) is considered the gold standard method to assess TBW, however in Spain there are not any reference data using D2DT. The knowledge of specific references for Spanish population must be a goal for the biological studies of Spanish people. OBJECTIVE: It was our aim to assess TBW using the D2DT in a sample of Spanish adolescents. METHODS: 224 specimens of urine from 150 adolescents (113 girls and 111 boys) were taken to analyze. A dose of 0.1 grams of 2D2O per Kg of body weight was administrated; afterwards it was followed by 4-hours stabilization period. The isotope (deuterium oxide (D2O)) dilution method was used to measure TBW with an isotope-ratio mass-spectrometer. Averages by sex and Tanner stages were calculated for %TBW and TBW. General lineal model were used to analyze differences and interactions between groups. RESULTS: %TBW was significantly different between boys and girls (58.98_5.59% vs 55.5_4.28%, P0.05). CONCLUSIONS: This study has been the first in Spain, which have measured TBW in vivo using D2DT. These data can be useful to validate new methods and equations from bioimpedance analysis to estimate TBW.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Coca-Col

Effects of land vs. Aquatic plyometric training on vertical jump

El objetivo de este estudio fue comparar los efectos de dos programas de entrenamiento pliométrico (inmersión vs. seco) sobre el salto vertical. 65 hombres físicamente activos fueron asignados aleatoriamente a tres grupos: entrenamiento pliométrico acuático (EPA, n 20), entrenamiento pliométrico (EP, n=20) y grupo control (GC, n=25). Los grupos EPA y EP entrenaron 2 sesiones por semana durante 10 semanas, mientras que GC no realizó entrenamiento alguno. El volumen de entrenamiento fue aumentado desde 10 series de 10 repeticiones en la primera semana hasta 10 series de 55 repeticiones en la última. Tanto EPA como EP aumentaron su rendimiento en CMJ y SJ con respecto al pretest (P≤0,001) sin encontrar diferencias significativas entre grupos, mientras que GC no mostró cambios. Como conclusión, el EPA puede ser un método alternativo a EP ya que ambos producen similares mejoras sobre el salto vertical y el estrés mecánico producido por EPA es menoThe aim of this study was to compare the effects of two plyometric training program (aquatic vs. land) on vertical jump. 65 male physical education students took part in this study and were randomly assigned to three groups: aquatic plyometric training group (APT, n = 20), plyometric training group (PT, n = 20) and control group (CG, n = 25). The training program was performed for 10 weeks with a frequency of 2 sessions per week. Volume was increased from 10 sets of 10 repetitions to 10 sets of 55 repetitions. Both APT and PT increased the performance in CMJ and SJ with respect to pretest (P ≤ .001), whereas CG remained unaltered. No statistically significant difference was observed between APT and PT. In conclusion, APT may be an alternative method to PT, because both training protocols have produced similar gains in the vertical jump, but APT might cause lower mechanical stres

Physiological responses in a simulated canarian wrestling contest

La Lucha Canaria (LC) ha sido recientemente reconocida como deporte por el Consejo Superior de Deportes, aunque su origen se pierde en el tiempo. Sin embargo, no hay ningún trabajo en la bibliografía científica que describa qué ocurre fisiológicamente durante la competición en esta modalidad de lucha, y éste es el objetivo del presente trabajo. Con una muestra de 12 luchadores de alto nivel (puntales) simulamos el sistema de competición actual en Lucha Canaria. Se estudió la frecuencia cardiaca, la tensión arterial y la concentración de lactato en sangre en diferentes momentos de la simulación. Los patrones observados de respuesta de FC, TA y lactato, caracterizan a la competición en LC como un ejercicio intermitente, con picos de intensidad que superan el umbral láctico y determinan incrementos importantes de FC y TA sistólica. Este estudio es el primero en que se valora la respuesta fisiológica del luchador canario en competición.The aim of this article is to describe what happens from a physiological point of view in a Canarian Wrestling (CW) contest. The Spanish National Sports Council recognized Canarian Wrestling as a sport on June 1st, 2009, although its origin is not very well documented. No scientific article exists in the scientific literature to describe what happens physiologically during a CW contest. Twelve high level wrestlers were recruited to simulate a CW match. The study involved data about heart rate (HR), blood pressure (BP) and blood lactate levels (L) at different moments of the combat. The conclusions of the data observed concerning HR, BP and L classify Canarian Wrestling as an intermittent exercise, with intensity peaks that exceed the lactic threshold and high levels of HR and systolic BP. This is the first paper in which the physiological responses in a Canarian Wrestling competition are reported

Differentially expressed genes in platinum-resistant high-grade serous ovarian cancer

Objectives: The purpose of this study was to identify genes and pathways differentially expressed in platinum resistant high grade serous ovarian cancer (HGSOC) when compared to sensitive HGSOC. Methods: A total of 37 patients with HGSOC tissue samples underwent RNA sequencing performed by TEMPUS (N=37, 21 platinum sensitive, 16 resistant; 85% Stage III-IV; 58% received neoadjuvant chemotherapy). RNA gene expression data and significantly impacted pathways were analyzed using Advaita Bio\u27s iPathwayGuide. Differentially expressed (DE) genes were identified using FDR of 0.05 and fold-change of 1.5. Genes from several impacted canonical metabolic pathways were validated by PCR against external data sets in a separate ovarian cancer sample group (n=15), platinum resistant ovarian cancer mouse tumor model, and wild-type sensitive and platinum resistant ovarian cancer cell lines. Relative gene expression was calculated using the comparative Ct method, also referred to as the “2 DDCT”, using L27 as internal control gene. Results: We identified 177 differentially expressed (DE) genes out of a total of 16,607 genes (1.1%) with measured expression. 15 pathways were found to be significantly impacted. Of the 15 canonical pathways, all were up regulated in the resistant HGSOC and the majority of the most significantly altered (5/10) were related to metabolism (Retinol metabolism (p-value = 0.002); Tyrosine Metabolism (p-value = 0.005); Tryptophan Metabolism (p-value = 0.009); and Phenylalanine Metabolism (p-value = 0.012); CYP Drug Metabolism (p-value = 0.022)). A total of 3 separate genes from the CYP family and two from the Dopa Decarboxylase family of genes were validated against an external data set of human ovarian tissue samples, cell lines, mouse ovarian tumor model, and found to have similarly increased gene expression in the genes tested in the platinum resistant groups. Compilation of KEGG analysis and the common network genes revealed pathways associated with amino acid metabolism to be most significantly altered. Conclusions: We describe the identification of a unique transcriptomic profile associated with platinum resistance. Interestingly, the main pathways identified are related to metabolism, suggesting that the survival to chemotherapy demands a major metabolic adaptation. These findings also represent a first step towards the identification of biomarkers for the detection of chemo-resistant disease and metabolism-based drug targets specific for chemo-resistant tumors. Further validation of this model is required in order to determine its clinical value

Longitudinal differences of physical activity and adiposity in adolescents: a 2-year follow-up

It is commonly believed that boys are more physically active than girls, which could affect body composition changes during adolescence. One major point not always considered or controlled is the maturational differences between boys and girls of similar chronological age. So, it remains to be determined the importance of physical activity (PA) behaviors adjusted by sex and maturation on body composition modifications. This study complement the published results by evaluating the effects of gender, sexual maturation level on PA and body composition changes. PURPOSE: To explore PA and adiposity alterations in Spanish students during adolescence. METHODS: Sixty-eight healthy adolescents were followed-up during 2-year (32 girls and 36 boys). A PA score was estimated by Physical Activity Questionnaire (PAQ-A). Adiposity was assessed by anthropometric measurements, BMI and fat mass percent (FMP) were calculated using classical equation, and waist circumference (WC) as abdominal adiposity marker. Tanner’s maturation stages were evaluated. Three assessments were performed: September 2011, 2012 and 2013 (S1, S2, and S3, respectively). Repeated measures were carried out between three moments for all variables and adjusted by maturation level and sex. RESULTS: Significant differences for FMP were found between S1 and S2 (22.30±8.22 vs. 21.15±7.73, P<0.05); a significant interaction with sex was observed (P<0.05), but not for maturation. Regarding PA, S2 was significantly higher than S3 (2.68±0.68 vs. 2.23±0.72, P<0.001). An interaction between PA and maturation was statically significant (P<0.05). CONCLUSION: The main finding of this follow-up was a reduction in PA after S2 period without changes in adiposity. In opposite, a reduction of FMP was only significant between S1 and S2, while PA was not modified. Our results suggest that body composition and PA changes observed during adolescence are not parallel. Moreover, the interaction analysis highlighted that maturation affect PA behavior, but not sex.This work was supported by the Spanish Ministry of Education, Culture and Sport (AP2010-0583), Spanish Ministry of Economy and Competitiveness (DEP2011-30565) and Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech