Decimal Age Research Articles

Exploring the existence, strength, and independence of relative age and maturation selection biases: a case study in Gaelic football talent development programmes

Background Biological maturity and relative age player selection biases are well documented in youth sports. However, there has been limited examination of the relationship between these biases. Aim This study investigated the presence, strength, and independence of relative age and biological maturity selection biases in Gaelic football. Subjects and methods A total of 247 male players from U14 to U16, from two talent academies were assessed for relative age (decimal age (DA)) and biological maturity (discrepancy between biological and chronological age (BA-CA)). Results Relative age effects (RAE) were observed in the U14 (DA = 0.62, d = 0.40) and U15 squads (DA = 0.57. d = 0.26) only. A bias towards advanced maturity status was present at U14 (BA-CA = 0.60, d = 0.83), U15 (BA-CA = 0.78, d = 0.89), and U16 (BA-CA, d = 1.01). There was a trivial (U14, r(83) = −0.210; U15, r(88) = 0.060) and low (U16, r(76) = 0.352) correlation between relative age and maturity status. Conclusion Substantial maturity selection biases and, to a lesser degree, relative age biases are evident in youth Gaelic football. Critically, these biases are independent constructs. Coaches and policy makers should be educated on the distinct influences of relative age and maturation, and on strategies to address these biases.

Mitigating against relative age effects in youth Track & Field: Validating corrective adjustment procedures across multiple events

ObjectivesWith the aim to better identify talented Track & Field performance development, this study estimated the relationships between chronological (decimal) age with 60-m sprint, high jump, triple jump, and pole vault performance. Then, to mitigate against expected Relative Age Effects (RAEs), Corrective Adjustment Procedures (CAPs) were applied to an independent sample. DesignMixed-longitudinal design examining public data between 2005 and 2019. MethodsThe performances of 5339 Italian sprinters and jumpers (53.1 %) spanning 11.01–17.99 years of age were examined, with trendlines between chronological age and performance established. Related to an independent sample (N = 40,306; female 45.5 %), trendlines were then utilised to apply CAPs and adjust individual performance. Considering raw and adjusted performance data, RAE distributions were examined for the top 25 % and 10 % performers. ResultsFor all male and female events, quadratic models best summarised the relationships between chronological age and performance (R2 = 0.74–0.89). When examining independent athletes in similar event, RAEs were more pronounced in males (Cramer's V = 0.35–0.14) than females (Cramer's V = 0.29–0.07). For both sexes, RAE magnitude decreased with age and increased according to performance level (i.e., Top25%–Top10%). However, following CAP applications, RAEs were reduced or removed within annual age groups and performance levels. ConclusionsWith RAEs prevalent across Italian youth Track & Field events, findings validate CAPs as a strategy to account for the influence of relative age differences on athletic performance. CAPs help establish a more equitable strategy for performance evaluation and could help improve the efficacy of long-term athlete development programming.

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

BackgroundFat 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.ObjectiveThe purpose of the study was to validate Body Surface Area (BSA) as an anthropometric indicator to estimate FFM in young basketball players.MethodsA 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.ResultsThree 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).ConclusionsThe 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.

Editorial

Editorial

The Intervention Program effect on the Quality of Children’s Body Posture at Elementary Education Level

The goal of this research was to determine the impact of an intervention program containing music-accompanied sport and dance activities on the quality of pupils’ body posture at the elementary level of education in physical and sports education classes. The research sample comprised Ʃ 102 pupils at the primary level of education, 53 of whom were boys with a decimal age of 8.83±0.69 and 49 were girls with a decimal age of 8.77±0.68. They were subjected to testing according to the Klein and Thomas method modified by Mayer. The output results of the posture diagnostics confirmed the significant effect of targeted exercises on the overall posture of boys with a substantial effect (Z=-6.131, p<0.05, r=0.60 – substantial effect). The greatest influence in the boys’ group was confirmed in the general spine curvature in the sagittal plane (Z=-5.209, p<0.05, r=0.51 – substantial effect). In the girls’ group, the targeted movement program was confirmed to have a substantial effect on overall body posture (Z=-5.793, p<0.05, r=0.59). In all other segments, it was significantly manifested with a medium effect. It was concluded that none of the participants had flawless posture. After the application of the intervention program, good posture was demonstrated by 62.2% of boys and 61.1% of girls. In the output test, the posture of 37.7% of boys and 38.8% of girls was incorrect. None of the pupils was diagnosed with very bad posture after the application of the intervention program. The relationship between BMI and posture assessment of the respondents was assessed. The results of the correlation of BMI values (r=0.007, p>0.05) and overall body posture did not show statistical dependence in both sexes. The intervention program including music-movement and dance elements had a significant effect on improving the posture quality of both boys and girls. The program supported by a musical piece was perceived positively by the pupils for its variety and emotionality. The program should be applied in the physical education classes at a frequency of minimum 2 times a week.

Relationship between relative age measured through decimal age, physical variables and anthropometry in elite youth soccer players

ABSTRACT Introduction Age differences between athletes born in the same year, as well as an over-representation of older players, are known as the Relative Age Effect (RAE). Players born at the beginning of the selection year have a physical and anthropometric advantage over their younger peers. Experts keep looking for new prediction variables for talent identification. Objectives The aim of the study is to correlate anthropometric, strength and power variables with the relative age (RA) and the level of the teams in which players played in each age category. Methods All players (N = 366) from an elite soccer academy of a Spanish club volunteered to participate in the study (U23-U10). Results There was a significant correlation between the RA of the players and the level of the team in which they played in each age category but no correlation between trimester of birth and level of the team. We found significant correlations between the players’ physical capacities, anthropometry, RA and the level of the team in which they played for the same age category, mainly from U16 to U10. U23 did not show any correlation between RA and physical or anthropometric variables. Conclusion Coaches should be cautious of choosing players based only on anthropometric or physical attributes.

Glenohumeral Joint Range of Motion in Crossminton Players

Crossminton is a sport that combines elements of squash, badminton and tennis, creating a new sport, which is currently being played all over the world. The aim of our study was to identify and compare the bilateral differences in the internal and external rotation of the glenohumeral joint of crossminton players. The subject of our study were 13 crossminton players from Slovak Republic (25.1±9.3 years; 172.8±9.1 cm; 71.8±16.1 kg). The range of motion of internal (IR-ROM) and external rotation (ER-ROM) of the glenohumeral joint was measured bilaterally using a standard two-arm goniometer. Bilateral comparison, decimal and sport age pairwise comparisons were carried using the T-test for independent samples. Results point to the occurrence of glenohumeral joint adaptation. Given the bilateral differences, the dominant shoulder has lower IR-ROM (p < 0.05) and higher ER-ROM (p < 0.05) than the non-dominant shoulder. GIRD (IR difference > 13 °) was observed in 4 players. The decimal age of the players did not have a significant impact on the rotation values of the glenohumeral joint. Only IR-ROM of the dominant upper limb was lower with the growing sport age of the players (p < 0.05). Given the fact that adaptations in ROM of glenohumeral joint promote an increased injury risk, the present study reveals the relevance of monitoring and finding differences between upper limbs in crossminton players.

Ultrasound Imaging-Based Methods for Assessing Biological Maturity during Adolescence and Possible Application in Youth Sport: A Scoping Review.

Bone maturity is an indicator for estimating the biological maturity of an individual. During adolescence, individuals show heterogeneous growth rates, and thus, differences in biological maturity should be considered in talent identification and development. Radiography of the left hand and wrist is considered the gold standard of biological maturity estimation. The use of ultrasound imaging (US) may be advantageous; however, its validity and reliability are under discussion. The aims of this scoping review are (1) to summarize the different methods for estimating biological maturity by US imaging in adolescents, (2) to obtain an overview of the level of validity and reliability of the methods, and (3) to point out the practicability and usefulness of ultrasound imaging in the field of youth sports. The search included articles published up to November 2022. The inclusion criteria stipulated that participants had to fall within the age range of 8 to 23 years and be free of bone disease and fractures in the region of interest. Nine body regions were investigated, while the hand and wrist were most commonly analyzed. US assessment methods were usually based on the estimation of a bone maturity stage, rather than a decimal bone age. Furthermore, 70% of the assessments were evaluated as applicable, 10% expressed restraint about implementation, and 20% were evaluated as not applicable. When tested, inter- and intra-rater reliability was high to excellent. Despite the absence of ionization, low costs, fast assessment, and accessibility, none of the US assessments could be referred to as a gold standard. If further development succeeds, its application has the potential to incorporate biological age into selection processes. This would allow for more equal opportunities in talent selection and thus make talent development fairer and more efficient.

Corrective Adjustment Procedures as a strategy to remove Relative Age Effects: Validation across male and female age-group long jumping

ObjectivesTo validate the application of Corrective Adjustment Procedures for removing Relative Age Effects in youth athletic contexts, this study estimated the longitudinal relationships between decimal age (chronological and relative) and performance in male and female long jumpers. Using trendlines, Corrective Adjustment Procedures were applied, and Relative Age Effect distributions associated with performance attainment were re-examined. DesignRetrospective longitudinal design examining competitive long-jump data between 2005 and 2019. MethodsIn Part I, participants were 689 junior Italian long jumpers (age range = 11.01–17.99 years; 56.6% females) who participated in ≥three events. Longitudinal modelling and regression equations quantified the sex-specific relationships between decimal age and long jump performance. In Part II, equations were utilised to adjust individual performance within an independent sample (N = 13,639; 50.1% females) of age-matched jumpers. Relative Age Effect distributions within attainment levels (i.e., Top 25–10%) were examined based on raw and correctively adjusted performance. ResultsIrrespective of sex, Relative Age Effects were prevalent across all age-groups with medium-large effect sizes at 12–17 (males and females) and 12–17 years (females) of age (Cramer's V range = 0.07–0.28). Relative Age Effect bias magnitude also increased with attainment level (i.e., Top 25–10%). Following Corrective Adjustment Procedure application, typical Relative Age Effects were removed with non-significant deviations in relative age distributions regardless of sex or age-group or attainment level (Top 25 or 10%). ConclusionsFindings provide efficacy for Corrective Adjustment Procedure application to remove Relative Age Effects across youth long jumping events. Corrective Adjustment Procedures suggest potential in improving performance evaluation, identification of technically skilled performers, and sporting experiences.

Detection of female volleyball player body composition uzing bioelectric impedanse analysis: cross-sectional study

Purpose: In today's sport, and especially in high-performance sports where volleyball also belongs, continuous monitoring of Body Composition (BC) can significantly regulate the training process, which has a positive effect on the top form of athletes. Aim of the current study was to assess and analyze the body composition of a female volleyball players VC "Jahorina", by Bioelectric Impedance Analysis (BIA). Material and methods: In study the participants consist 18 female volleyball players, the members of the Volleyball Club ''Jahorina'' from Pale, East Sarajevo City (Body height = 173 ± 8.77 cm; Body weight = 66.04 ± 9.09kg; BMI = 22.03 ± 2.19 kg/m², decimal age 19.11 ± 2.63 years old) who competes in the Premier League of Bosnia and Herzegovina (B&H). Results: of the study showed that the body composition is within the healthy (allowed) values recommended for this population of volleyball players (Body Fat = 24.82%; Body Fat=11.44kg; Body Water = 53.68%; Body Muscle = 47.09 kg, BMR = 1538.08; DCI = 6435.38, etc.). Conclusion: Compared to the results of other authors, that Jahorina volleyball players do not lag far behind European clubs in terms of weaker BC (BF%, BFkg, BW%, BMkg, BMR, DCI, BMI, etc.). The only place where they are inferior is the body height of the volleyball player (height = 173 ± 8.77 cm), while the relative value of Body weight = 66.04 ± 9.09 kg is evident.

The Relationship between Foot Status and Motor Status in Preschool Children: A Simple, Comparative Observational Study.

Background: The research objective of the study is to determine the differences in the manifestation of the motor status of normally fed preschool test subjects, classified into groups according to foot status. Methods: This is a simple, comparative observational study. Preschool children included in this study have been subjected to anthropometric measurements in order to determine BMI, tests for motor skills assessment (running at 20 m from a high start, standing broad jump, backwards polygon, rectangular seated forward bend, plate tapping, sit-ups for 60 s, and bent arm hang), and a determination of foot status. The total sample was comprised of 202 test subjects who attended a regular sports program, aged 3.9 to 6.5 years of decimal age (M = 141; Age = 5.3 ± 0.74; Height = 117.3 ± 7.1; Weight = 22 ± 3.7; F = 61; Age = 5.1 ± 0.73; Height = 114.9 ± 7.4; Weight = 21.2 ± 3.8), of which 153 (75.7%) were normally fed, 6 (3%) were undernourished, 30 were overweight (14.9%), and 13 were obese (6.4%). Results: In the total sample, 30 (14.9%) subjects had normal arch feet, 90 (44.6%) high arched feet, and 41 (20.3%) flat feet. We found 41 (20.3%) subjects who had different left and right foot statuses within this sample. The data were processed by means of nonparametric tests (the Kruskal–Wallis and Mann–Whitney U tests) at a significance level p ≤ 0.05. Conclusion: The results show that there is a statistically significant difference between groups of subjects with different foot statuses in the manifestation of motor status in most tests, with a significance level of p ≤ 0.01, and in tests of sit-ups for 60 s and the bent arm hang, there is a statistically significant difference, the level of which is p ≤ 0.05. It is only in the inclination test of rectangular seated forward bend that no statistically significant difference was displayed.

EFFECT OF HIGH AND LOW FLEXIBILITY ON AGILITY, ACCELERATION SPEED AND VERTICAL JUMP PERFORMANCE OF VOLLEYBALL PLAYERS

This study aimed to assess the effect of high and low levels of flexibility on key performance indicators of volleyball performance. Eighty-four volleyball players (n=84; mean±SD; decimal age: 16.57±1.51; height (cm): 176.23±8.77; body mass (kg): 66.14±11.79) were selected for the study. The design of the study was cross-sectional and to measure selected variables i.e. agility, lower body muscular power, and acceleration speed; 6×10 m shuttle run, countermovement jump (with arm swing) test and 20 m sprint test (standing start) were used. To measure the flexibility level of the players, sit and reach test was used. Shapiro-Wilk normality test was conducted to check the distribution of data and the Levine test was applied to check homogeneity of the variance in data. Participants were divided into two groups i.e. High Flexibility Group (HFG) and Low Flexibility Group (LFG) using k-means cluster analysis and independent t-test was applied to find the differences between HFG and LFG. The level of significance was set at p < 0.05. Results showed statistically significant difference between HFG and LFG in agility, acceleration speed and lower body muscular power and, based on the results, it was concluded coaches should include flexibility training in the regular training programme. The results obtained supported the rationale that baseline flexibility may influence the performance of volleyball players.
 
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Ultrasonographic evaluation of the wrist and elbow joints: A pilot study to explore a non-invasive technique for age estimation.

Age estimation is a vital aspect of the process of identification. Studying the appearance and fusion of long bones is one of the most commonly used methods for age estimation. Most research conducted on age estimation using the study of the appearance and fusion of ossification centres has been roentgenographic in nature. However, X-ray examination and computed tomography examination are associated with ionisation radiation. The present study investigated the use of ultrasonography (USG) as a means of visualising ossification centres of the elbow and wrist joints for age estimation in 31 Maharashtrian boys from Ahmednagar, India. The Schmeling etal. method of grading was used to score the fusion of ossification centres, and simple and multiple linear regression models were developed for age estimation. It was found that the ossification centres of the elbow and wrist joints followed a set pattern of maturation and fusion. The ossification centres of the elbow joint fused before the ossification centres of the wrist joint. The fusion scores of proximal radial epiphyses had the highest correlation with the decimal age of the participants, making its fusion the best indicator among all the ossification centres examined in this study for age estimation. Regression models to estimate age were generated using all the ossification centres. USG was found to be suitable for the purpose of age estimation based on ease of examination, minimal ionisation risks, its non-invasive nature and clear visualisation of ossification centres.

Testing the application of corrective adjustment procedures for removal of relative age effects in female youth swimming

ABSTRACT The purpose of this study was (1) accurately estimate longitudinal relationships between decimal age (i.e., chronological and relative) and performance in Australian female 100 m (N = 765) and 200 m (N = 428) Breaststroke swimmers (10–18 years); and (2) determine whether corrective adjustment procedures could remove Relative Age Effects (RAEs) in an independent sample of age-matched 100 m (N = 2,491) and 200 m (N = 1,698) state/national level Breaststroke swimmers. In Part 1, growth curve modelling quantified longitudinal relationships between decimal age and swimming performance. In Part 2, relative age distributions (Quartile 1–4) for “All”, “Top 25%” and “10%” of swimming times were examined based on raw and correctively adjusted swim times for age-groups. Based on raw swim times, finding identified RAE effect sizes increased in magnitude (small-medium) with selection level (“All”-“Top 25%”) in 12–14 years age-groups for both events. However, when correctively adjusted swim performances were examined, RAEs were primarily absent across all age-groups and selection levels. Using longitudinal reference data, corrective adjustment procedures removed relative age advantages in female youth Breaststroke performance. Removing the influence of relative age-related differences is predicted to improve the accuracy of identifying genuinely skilled youth swimmers.

The Effect of Biological Age in the Evaluation of Physical Indicators and the Changes in Selected Motoric Tests of Young Female Basketball Players

Summary Basketball is a complex team sport, which combines cyclic and acyclic motion structures consisting mainly of fast and dynamic moves with or without a ball. The puberty is characterized by considerable variability that may occur earlier (developmental acceleration, early maturing) or later (developmental retardation, late maturing): an example can be a 12-year-old girl whom biological age could range from 9.5 to 14.5 years. For this study we selected 6 girls-players from the whole team. Two players were according to the norms from the zone of developmental retardation (BioRet), two players whose decimal and biological age i.e. bone age was identical (DC = BV), and the other two were in the biological acceleration zone (BioAkc.). All players were 13-years old and competed in the U14 category. We have confirmed that there are great differences in biological age in a group of 13-years old girls – in our research it has shown almost four years difference. We did not confirm the author's conclusions that biologically accelerated individuals achieved better results than the retarded ones in the speed and strength tests.

Removing relative age effects from youth swimming: The development and testing of corrective adjustment procedures

Objectives(1) Generate accurate estimates of the relationship between decimal age (i.e., chronological and relative) with swimming performance based on longitudinal data. (2) Determine whether corrective adjustment procedures can remove Relative Age Effects (RAEs) from junior/youth swimming. DesignLongitudinal and repeated years of cross-sectional performance data were examined. Methods(1) Participants were 553 male 100m Freestyle swimmers (10–18 years) who participated in ≥five annual events between 1999–2017. Growth curve modelling quantified the relationship between age and swimming performance, permitting corrective adjustment calculations. (2) Participants were N=2141 male 100m Freestyle swimmers (13–16 years) who swam at state/national events in 2015–2017. Relative age distributions for ‘All’, ‘Top 50%’, ‘25%’ and ‘10%’ of swimming times were examined based on raw and correctively adjusted swim times. Chi-square, Cramer’s V and Odds Ratios (OR) determined whether relative age (quartile) inequalities existed according to age-groups, selection level and correctively adjusted swim times. ResultsBased on raw swim times, for ‘All’ swimmers RAEs was evident at 13 and 14 years-old and dissipated thereafter. But, RAE effect sizes substantially increased with selection level, with large-medium effects between 13–15 years-old (e.g., 15 years — Top 50% Q1v Q4 OR=2.28; Top 10%=6.02). However, when correctively adjusted swim times were examined, RAEs were predominantly absent across age-group and selection levels. ConclusionsWith accurate longitudinal reference data, corrective adjustment procedures effectively removed RAEs from 100m Freestyle swimming performance, suggesting the potential to improve swimming participation experience and performance evaluation.

Português

Objective: The objective of this study was to evaluate the physical growth, biological maturation and motorperformance of children and adolescents in the mid-west baseball team (Atibaia, Campinas and Indaiatuba) Brazil; in the Pre-Junior category, runner-up of the Inter-seleccoes tournament of the year 2018. The specific objectives were: a) to compare thephysical growth with references of students of Campinas-2014 and international reference of CDC-2012; and b) to compare therelationship between motor performance and biological maturation classification. Methodology: A cross-sectional descriptivestudy was carried out. The sample consisted of twenty three (23) young male athletes between 12 and 14 years of age. Thevariables of decimal age, height, body weight, trunk-cephalic stature were evaluated. The Body Mass Index (BMI), the BodyComposition in the four components (Fat, Muscular, Bone and Residual Mass) were calculated. Biological maturation wasdetermined by the Peak Growth Rate (PVC). Motor performance was determined by abdominal muscle resistance test,horizontal jump without impulse, medical ball throw (2Kg), 30 and 50 meter run and manual pressure force. Results: It wasdetermined that (PVC) of baseball players is reached at (13.9 years) (0.4SD). In relation to the physical growth, athletes who are(-1 year of PVC) are shorter than those of the references, as regards weight and (BMI) present values slightly above the 50thpercentile. While athletes who are (in the year of PVC) have a height and weight equal to or above the 75th percentile and (BMI)below the 75th percentile.

Level of Internet use among Greek adolescents with type 1 diabetes.

Background Compulsive Internet use has emerged as a contemporary addictive behavior. Our aim was to investigate the reasons for Greek adolescents with type 1 diabetes mellitus (T1DM) and their families to use the Internet and additionally to investigate the level of Internet use and its associations to demographic, socio-economic parameters and glycemic control. Methods Patients with T1DM, aged >12 years and their parents were recruited during their regular visits to the Pediatric Diabetes Clinic. A similar group of healthy children, age- and sex-matched served as a control group. All participants were asked to fill out the Greek translated version of the Internet Addiction Test (IAT). Caregivers of patients with T1DM were asked to complete a second questionnaire consisting of questions regarding demographic and socio-economic data of the family and data concerning disease management. Results Thirty-five patients with T1DM (mean decimal age of 14.95 ± 1.90 years) and 35 controls participated in the study. Nine patients were on an insulin pump whereas the rest were on multiple daily injections. The mean total score of the patients' IAT questionnaires was significantly lower compared to the controls (26.26 ± 12.67 vs. 39.91 ± 18.55, p = 0.003). Controls were characterized as exhibiting moderate addictive behavior at a significantly higher percentage than patients (31.43% vs. 2.86%, p = 0.002). All patients on insulin pumps demonstrated normal Internet use. Mild addictive behavior was associated with a lower parental educational level. Finally, level of Internet use (IAT score) was positively associated to glycemic control (HbA1c value) with a correlation that was approaching significance (r = 0.315, p = 0.065). Conclusions Adolescents with T1DM and especially those on an insulin pump exhibit normal Internet use compared to their healthy peers. Time consumed on Internet correlates reversibly with glycemic control.

Reelin blood levels as a marker of some types of autistic spectrum disorders (ASD)

Objective: Reelin is a large glycoprotein secreted from specific neurons within the developing brain and encoded by RELN gene. Reelin regulates the signaling pathway of post-mitotic neurons to reach the proper layer of the central nervous system parenchyma, suggesting that deficiencies in the expression of RELN gene could play a role in the genesis of schizophrenia and ASD. Our aim is to find differences in the blood expression of Reelin between ASD patients and controls. Methods: A referral group of 30 ASD patients (27 boys and three girls) (Mean decimal age= 7.84±3.4 SD) were recruited from the neuropaediatric outpatient clinic of a secondary hospital. After meeting the criteria for ASD diagnosis, we invited the families to donate an aliquot from a blood test, required for clinical reasons. Samples were analyzed for plasma Reelin protein levels by Western blots. Other 10 patients (four boys and six girls) (Mean decimal age= 8.5±4.5 SD) suffering from minor neurologic symptoms such as headaches, dizziness, varied paroxysms and who also required a blood analysis (with normal results) accepted to join the study as controls. The data were tabulated and analyzed with the EpiInfo 7.2 statistical package, following the directions of the local ethics committee. Results: Sixteen patients of the ASD group (53.33%) showed Reelin values over the normal range, while only one from the control group did it (10%) being these differences statistically significant (OR=10.3; CI:1.15-91.6). Sixteen boys (56.61%) and one girl (11.11%) of the whole group showed elevated Reelin values near of statistical significance (OR=8.5; CI:0.95-76.6). Conclusion: In our series, patients suffering from ASD are 10 times more likely to present high Reelin blood levels than controls, suggesting the possibility that Reelin blood levels could be a suitable marker of some ASD types, although gender could play the role of a confusing factor.

Determinant Factors of Long-Term Performance Development in Young Swimmers.

To develop a performance predictor model based on swimmers' biomechanical profile, relate the partial contribution of the main predictors with the training program, and analyze the time effect, sex effect, and time × sex interaction. 91 swimmers (44 boys, 12.04 ± 0.81 y; 47 girls, 11.22 ± 0.98 y) evaluated during a 3-y period. The decimal age and anthropometric, kinematic, and efficiency features were collected 10 different times over 3 seasons (ie, longitudinal research). Hierarchical linear modeling was the procedure used to estimate the performance predictors. Performance improved between season 1 early and season 3 late for both sexes (boys 26.9% [20.88;32.96], girls 16.1% [10.34;22.54]). Decimal age (estimate [EST] -2.05, P < .001), arm span (EST -0.59, P < .001), stroke length (EST 3.82; P = .002), and propelling efficiency (EST -0.17, P = .001) were entered in the final model. Over 3 consecutive seasons young swimmers' performance improved. Performance is a multifactorial phenomenon where anthropometrics, kinematics, and efficiency were the main determinants. The change of these factors over time was coupled with the training plans of this talent identification and development program.