IL11RA-related Crouzon-like autosomal recessive craniosynostosis in 10 new patients: Resemblances and differences.

By describing 10 new patients recruited in centres for Human Genetics, we further delineate the clinical spectrum of a Crouzon-like craniosynostosis disorder, officially termed craniosynostosis and dental anomalies (MIM614188). Singularly, it is inherited according to an autosomal recessive mode of inheritance. We identified six missense mutations in IL11RA, a gene encoding the alpha subunit of interleukin 11 receptor, 4 of them being novel, including 2 in the Ig-like C2-type domain. A subset of patients had an associated connective tissue disorder with joint hypermobility and intervertebral discs fragility. A smaller number of teeth anomalies than that previously reported in the two large series of patients evaluated in dental institutes points toward an ascertainment bias.

Novel genetic risk factors for asthma in African American children: Precision Medicine and the SAGE II Study.

Asthma, an inflammatory disorder of the airways, is the most common chronic disease of children worldwide. There are significant racial/ethnic disparities in asthma prevalence, morbidity, and mortality among US children. This trend is mirrored in obesity, which may share genetic and environmental risk factors with asthma. The majority of asthma biomedical research has been performed in populations of European decent. We sought to identify genetic risk factors for asthma in African American children. We also assessed the generalizability of genetic variants associated with asthma in European and Asian populations to African American children. Our study population consisted of 1227 (812 asthma cases, 415 controls) African American children with genome-wide single nucleotide polymorphism (SNP) data. Logistic regression was used to identify associations between SNP genotype and asthma status. We identified a novel variant in the PTCHD3 gene that is significantly associated with asthma (rs660498, p = 2.2 × 10(-7)) independent of obesity status. Approximately 5 % of previously reported asthma genetic associations identified in European populations replicated in African Americans. Our identification of novel variants associated with asthma in African American children, coupled with our inability to replicate the majority of findings reported in European Americans, underscores the necessity for including diverse populations in biomedical studies of asthma.

Anthropometry, Physical Fitness and Coordination of Young Figure Skaters of Different Levels.

The aim of the present study was to identify anthropometric, physical, coordinative and ice-skating specific characteristics that discriminate young elite ice skaters from non-elite skaters and their non-skating peers. 32 skaters aged 9-12 years old (11 elites and 21 non-elites) voluntarily participated in the study. They were submitted to 5 anthropometric, 7 physical, 3 coordination and 5 ice-skating specific tests. Reference values of a representative healthy non-skating sample were taken from the Flemish Sports Compass dataset. Figure skaters appeared to be predominantly average mature (93.8%), were lighter and leaner than the reference sample, and demonstrated better physical characteristics and motor coordination. There was no difference between the elite and non-elite group regarding maturity status and anthropometric or physical parameters. Still, elite skaters scored better than non-elites on the coordination tests jumping sideways and tended to do so on the moving sideways test. Profiles of figure skaters differ clearly from a reference population, while non-sport-specific motor coordination tests allow discrimination between elite and non-elite skaters. The relevance of these findings with respect to talent detection and identification in young ice skaters are discussed.

Talent in Female Gymnastics: a Survival Analysis Based upon Performance Characteristics.

This study investigated the link between the anthropometric, physical and motor characteristics assessed during talent identification and dropout in young female gymnasts. 3 cohorts of female gymnasts (n=243; 6-9 years) completed a test battery for talent identification. Performance-levels were monitored over 5 years of competition. Kaplan-Meier and Cox Proportional Hazards analyses were conducted to determine the survival rate and the characteristics that influence dropout respectively. Kaplan-Meier analysis indicated that only 18% of the female gymnasts that passed the baseline talent identification test survived at the highest competition level 5 years later. The Cox Proportional Hazards Model indicated that gymnasts with a score in the best quartile for a specific characteristic significantly increased chances of survival by 45-129%. These characteristics being: basic motor skills (129%), shoulder strength (96%), leg strength (53%) and 3 gross motor coordination items (45-73%). These results suggest that tests batteries commonly used for talent identification in young female gymnasts may also provide valuable insights into future dropout. Therefore, multidimensional test batteries deserve a prominent place in the selection process. The individual test results should encourage trainers to invest in an early development of basic physical and motor characteristics to prevent attrition.

Longitudinal Development of Explosive Leg Power from Childhood to Adulthood in Soccer Players.

The aim of the this study was to investigate the development of explosive leg power by using 2 similar jumping protocols (countermovement jump and standing broad jump) in 555 Belgian, high-level young soccer players, aged between 7 and 20 years. The total sample was divided into 3 longitudinal samples related to growth and maturation (pre-teenchildhood: (6-10 years;), early adolescence: (11-16 years;) and late adolescence: (17-20 years)), and 6 multilevel regression models were obtained. Generally, both jumping protocols emphasized that chronological age, body size dimensions (by means of fat mass in the late childhood and early adolescence groups, fat-free mass in the late adolescence group and stature--(not for CMJ in late childhood group) and fat mass in the late childhood and early adolescence groups, and fat-free mass in the late adolescence group) and motor coordination (one item of a 3-component test battery) are longitudinal predictors of explosive leg power from childhood to young adulthood. The contribution of maturational status was not investigated in this study. The present findings highlight the importance of including non-specific motor coordination in soccer talent development programs.

The Yo-Yo intermittent recovery test level 1 is reliable in young high-level soccer players.

The aim of the study was to investigate test reliability of the Yo-Yo intermittent recovery test level 1 (YYIR1) in 36 high-level youth soccer players, aged between 13 and 18 years. Players were divided into three age groups (U15, U17 and U19) and completed three YYIR1 in three consecutive weeks. Pairwise comparisons were used to investigate test reliability (for distances and heart rate responses) using technical error (TE), coefficient of variation (CV), intra-class correlation (ICC) and limits of agreement (LOA) with Bland-Altman plots. The mean YYIR1 distances for the U15, U17 and U19 groups were 2024 ± 470 m, 2404 ± 347 m and 2547 ± 337 m, respectively. The results revealed that the TEs varied between 74 and 172 m, CVs between 3.0 and 7.5%, and ICCs between 0.87 and 0.95 across all age groups for the YYIR1 distance. For heart rate responses, the TEs varied between 1 and 6 bpm, CVs between 0.7 and 4.8%, and ICCs between 0.73 and 0.97. The small ratio LOA revealed that any two YYIR1 performances in one week will not differ by more than 9 to 28% due to measurement error. In summary, the YYIR1 performance and the physiological responses have proven to be highly reliable in a sample of Belgian high-level youth soccer players, aged between 13 and 18 years. The demonstrated high level of intermittent endurance capacity in all age groups may be used for comparison of other prospective young soccer players.

Cue usage in volleyball: a time course comparison of elite, intermediate and novice female players.

This study compared visual search strategies in adult female volleyball players of three levels. Video clips of the attack of the opponent team were presented on a large screen and participants reacted to the final pass before the spike. Reaction time, response accuracy and eye movement patterns were measured. Elite players had the highest response accuracy (97.50 ± 3.5%) compared to the intermediate (91.50 ± 4.7%) and novice players (83.50 ± 17.6%; p<0.05). Novices had a remarkably high range of reaction time but no significant differences were found in comparison to the reaction time of elite and intermediate players. In general, the three groups showed similar gaze behaviour with the apparent use of visual pivots at moments of reception and final pass. This confirms the holistic model of image perception for volleyball and suggests that expert players extract more information from parafoveal regions.

A longitudinal analysis of gross motor coordination in overweight and obese children versus normal-weight peers.

BACKGROUND: The relationship of childhood overweight (OW) and obesity (OB) with motor skill and coordination is gaining due attention; however, longitudinal evidence is currently lacking. OBJECTIVE: The dual purpose of this study was (1) to investigate the short-term evolution in the level of gross motor coordination according to children's weight status, and (2) to identify those factors predicting their gross motor coordination performance over a 2-year interval. SUBJECTS: Participants were 50 children with OW, including 8 with OB (aged 6-10 years at baseline, with 52% boys), and 50 with normal-weight (NW) matched for gender and age. MEASUREMENTS: Anthropometrics (body height, body weight, body mass index (BMI), %body fat) and level of gross motor coordination (Körperkoordinationstest für Kinder, KTK) were assessed in 2007 (baseline) and 2 years later in 2009 (follow-up). At baseline, participants completed a survey based on the Flemish Physical Activity Questionnaire (FPAQ) to obtain socio-demographic information and to determine physical activity levels in diverse domains. RESULTS: The evolution in the level of gross motor coordination over time was strongly related to children's weight status. Participants in the NW group showed more progress than their OW/OB peers, who demonstrated significantly poorer performances. Accordingly, between-group differences in KTK outcomes (that is, raw item scores and total motor quotient) became more evident over time. Multiple linear regression analysis further indicated that, in addition to BMI per se (negative predictor), participation in organized sports within a sports club (positive predictor) determines gross motor coordination performance(s) 2 years later. CONCLUSION: Our results provide conclusive evidence for an increasingly widening gap of OW/OB children's gross motor coordination relative to NW peers across developmental time in the absence of targeted initiatives. Special attention is thus needed for OW/OB children, especially for those not practicing sports in a club environment, in terms of motor skill improvement to promote regular participation in physical activity.

Relative age, biological maturation and anaerobic characteristics in elite youth soccer players.

Being relatively older and having an advanced biological maturation status have been associated with increased likelihood of selection in young elite soccer players. The aims of the study were to investigate the presence of a relative age effect (RAE) and the influence of birth quarter on anthropometry, biological maturity and anaerobic parameters in 374 elite Belgian youth soccer players. The sample was divided into 3 age groups, each subdivided into 4 birth quarters (BQ). Players had their APHV estimated and height, weight, SBJ, CMJ, sprint 5 and 30 m were assessed. Overall, more players were born in BQ1 (42.3%) compared with players born in BQ4 (13.7%). Further, MANCOVA revealed no differences in all parameters between the 4 BQ's, controlled for age and APHV. These results suggest that relatively youngest players can offset the RAE if they enter puberty earlier. Furthermore, the results demonstrated possible differences between BQ1 and BQ4, suggesting that caution is necessary when estimating differences between players because of large discrepancies between statistical and practical significance. These findings also show that coaches should develop realistic expectations of the physical abilities of younger players and these expectations should be made in the context of biological characteristics rather than chronological age-based standards.

The Use of Contextual Information for Anticipation of Badminton Shots in Different Expertise Levels.

Purpose: The current study investigated the use of contextual information for anticipation in badminton. Method: Participants were groups of elites (n = 26), competitive (n = 15) and novice players (n = 17) whose anticipation accuracy and reaction time were assessed using an ecologically valid badminton specific video-based occlusion test. Two conditions were presented, where either only kinematic information was available (Last Strokes condition, LS), or kinematic and contextual information were both available (Full Rally condition, FR). Results: Participants reacted slower in the FR condition, while no differences in accuracy were observed between the two conditions. Furthermore, all participants were better at side predictions than length, and elites outperformed novices in both side and length predictions. Among the elite group (which was split into adult elites, adult sub-elites & young elites), adult elite athletes showed faster responses for both the LS and FR conditions compared to their other elite counterparts who were much slower in both conditions. Conclusion: These results indicate that even at the highest level, anticipation performance can discriminate between groups of expert performers. In addition, the findings of this study indicate that the role of contextual information might not be as large as hypothesized, and further research is needed to clarify the role of contextual information toward anticipation.

Relative age effect and Yo-Yo IR1 in youth soccer.

The aims of the study were to investigate the presence of a relative age effect and the influence of birth quarter on anthropometric characteristics, an estimation of biological maturity and performance in the Yo-Yo Intermittent Recovery Test level 1 in 606 elite, Flemish youth soccer players. The sample was divided into 5 chronological age groups (U10-U19), each subdivided into 4 birth quarters. Players had their APHV estimated and height, weight and Yo-Yo IR1 performance were assessed. Differences between quarters were investigated using uni- and multivariate analyses. Overall, significantly (P<0.001) more players were born in the first quarter (37.6%) compared to the last (13.2%). Further, no significant differences in anthropometric variables and Yo-Yo IR1 performance were found between the 4 birth quarters. However, there was a trend for players born in the first quarter being taller and heavier than players born in the fourth quarter. Players born in the last quarter tended to experience their peak in growth earlier, this may have enabled them to compete physically with their relatively older peers. Our results indicated selection procedures which are focused on the formation of strong physical and physiological homogeneous groups. Relative age and individual biological maturation should be considered when selecting adolescent soccer players.

The contribution of growth and maturation in the functional capacity and skill performance of male adolescent handball players.

The present study determined to what extent the variance in performance might be explained by chronological age, biological maturation, training load and anthropometry in 168 Belgian male handball players aged 14 years: anthropometric, strength, speed and sport-specific skills were assessed. MANOVA tested the effect of chronological age and biological maturity, whereas MANCOVA was used to compare maturity groups controlling for chronological age and training load. In addition, canonical correlation analysis was used between age, maturity-offset and anthropometry, on one side, and performance and sport-specific skills, on the other side. Results revealed significant differences between early, on-time and late maturity groups for anthropometry (p<0.001), strength (p<0.001) and sprint 20-m (p<0.05) in favour of the early maturing players. The difference between the mean values of the extreme groups for height was 24.8 cm, for weight 33.2 kg and, for body fat 6.5%; for handgrip 20.2 kg, for 5-jump test 1.1 m and for 20-m sprint 0.20 s. Maturity status had no effect on sport-specific skills. Canonical correlations indicated that poorer scores in sport-specific skills were related to fatness and lack of training. In parallel, a substantial relationship was found between early maturity-offset, body size, strength and 20-m sprint.

Ovarian-sparing surgery for ovarian teratoma in children.

BACKGROUND: Ovarian teratoma (OT) is the most common ovarian neoplasm in children. Oophorectomy has been the standard treatment but may impair fertility. The aim of this study was to investigate the feasibility and outcome of ovarian-sparing surgery (OSS) for OT. PROCEDURE: We retrospectively studied all children treated for OT at a pediatric teaching hospital in Paris, France, between March 1992 and July 2006. OSS was performed when deemed technically feasible in patients who had no lymphadenopathy by preoperative imaging or surgical exploration, normal tumor marker levels, and calcifications on radiographs. RESULTS: We identified 30 patients, including 29 with unilateral OT and 1 with synchronous bilateral OT. Emergent surgery was performed in five patients, among whom four had ovarian torsion requiring oophorectomy and one underwent OSS. Of the 26 OTs in the 25 remaining patients, 10 were managed with OSS and 16 with oophorectomy. Subsequently, ultrasound monitoring detected OT development in the contralateral ovary in 4 (14%) patients, after a median of 3 years (range, 1-14 years); OSS was performed in all four cases. The patient with bilateral synchronous OT, managed by OSS initially, underwent unilateral oophorectomy 3 years later for a recurrence. Overall OSS was performed for 15 (42%) OTs. CONCLUSIONS: Our results suggest recommendations for preserving fertility whenever possible without compromising the oncological prognosis. In particular, OSS should be reserved for patients who meet all criteria for localized mature teratoma. Long-term follow-up is crucial.

The KörperkoordinationsTest für Kinder: reference values and suitability for 6-12-year-old children in Flanders.

An adequate coordination level in children is important for their general development, but also for health, psychosocial, academic and well-being-related reasons. In this study, the suitability of the KörperkoordinationsTest für Kinder (KTK) as an assessment instrument for the gross motor coordination was evaluated in 2470 children from 26 elementary schools for general education spread over the Flemish and Brussels-capital region. All children performed four subtests: walking backwards (WB), moving sideways (MS), hopping for height (HH) and jumping sideways (JS). Age and gender-specific values were established for the Flemish children anno 2008. Overall, the current sample scored significantly worse than their 1974 German counterparts (P<0.001). Score distribution showed 21% of the children being placed in the problematic range of gross motor coordination level. A decline in coordination was observed especially in those tasks relying primarily on coordinative capacities (WB and MS), while improvements or status quo in those tasks relying on strength and speed (JS and HH) were explained by secular trends. We suggest that the KTK is a valuable instrument for the assessment of the gross motor coordination of Flemish children and efforts should be made in order to face the decline in coordination.

Factors discriminating gymnasts by competitive level.

This study examined the relationship between the performance level as evaluated by expert coaches and the results on a multidimensional test battery in female gymnastics. 4 coaches assigned 168 female gymnasts aged 6-8 years into 2 groups (Elite-level potential, n=103 and Sub-elite-level potential, n=65) based upon their technical evaluation of the gymnastics abilities on the 4 apparatus. Moreover, anthropometric, physical and coordinative characteristics were assessed. ANOVA with age as fixed factor revealed that results on all aforementioned characteristics, except body fat%, sit-and-reach, rope climbing and a motor coordination test, significantly improved with increasing age. MANCOVA with competitive level as fixed factor and age and maturity as covariates indicated that all gymnasts portrayed a similar athletic built (Wilks' lambda=0.95, F=2.20, p=0.071), but the elite-level potential gymnasts outperformed the less gifted gymnasts on all physical (Wilks' lambda=0.65, F=8.00, p<0.001) and coordinative variables (Wilks' lambda=0.79, F=22.10, p<0.001). Discriminant analysis revealed motor coordination to be the most important factor in discriminating between young female elite and sub-elite gymnasts. A test battery measuring multidimensional performance characteristics is valuable in addition to the coaches' technical judgment in the search of young gifted female gymnasts.

Effects of optic flow on spontaneous overground walk-to-run transition.

Perturbations of optic flow can induce changes in walking speed since subjects modulate their speed with respect to the speed perceived from optic flow. The purpose of this study was to examine the effects of optic flow on steady-state as well as on non steady-state locomotion, i.e. on spontaneous overground walk-to-run transitions (WRT) during which subjects were able to accelerate in their preferred way. In this experiment, while subjects moved along a specially constructed hallway, a series of stripes projected on the side walls and ceiling were made to move backward (against the locomotion direction) at an absolute speed of -2 m s(-1) (condition B), or to move forward at an absolute speed of +2 m s(-1) (condition F), or to remain stationary (condition C). While condition B and condition F entailed a decrease and an increase in preferred walking speed, respectively, the spatiotemporal characteristics of the spontaneous walking acceleration prior to reaching WRT were not influenced by modified visual information. However, backward moving stripes induced a smaller speed increase when making the actual transition to running. As such, running speeds after making the WRT were lower in condition B. These results indicate that the walking acceleration prior to reaching the WRT is more robust against visual perturbations compared to walking at preferred walking speed. This could be due to a higher contribution from spinal control during the walking acceleration phase. However, the finding that subjects started to run at a lower running speed when experiencing an approaching optic flow faster than locomotion speed shows that the actual realization of the WRT is not totally independent of external cues.

Spatiotemporal characteristics of spontaneous overground walk-to-run transition.

The purpose of the current study was to examine spontaneous overground walk-to-run transitions (WRT). For the first time, subjects' WRT was examined during an overground protocol that allowed them to accelerate freely. The overground speed profile prior to reaching the WRT was analysed together with the spatiotemporal characteristics of the actual transition. Nine women (height: 166.4+/-3.5 cm) performed five spontaneous WRT. Speed, step frequency (SF) and step length (SL) of the accelerating walking steps and the transition step were determined. By means of fourth degree polynomials, subjects' spatiotemporal profiles prior to reaching WRT were determined. A step length index (SLI) was used to calculate the contribution of SF and SL to the increase in walking speed. Subjects took on average 5.9+/-0.9 walking steps prior to reaching transition. When speeding up towards the transition to running, subjects chose to accelerate predominantly in the first half of the walking acceleration period, followed by smaller speed increments in the second half. The SLI values indicated that subjects tended to increase walking speed by increasing SL, more than SF, except during the first 20% of the acceleration period. WRT-speed was 2.664+/-0.230 m s(-1), which was higher than in former treadmill studies using a constant acceleration protocol (+/-2.1 m s(-1)). Subjects made a speed jump of 0.417 m s(-1) from the last walking step to the WRT-step. We can conclude that further transition studies studying the interaction between the acceleration and gait transition behaviour are necessary in order to complete the understanding of the transition phenomenon.

The use of the Körperkoordinationstest für Kinder in the talent pathway in youth athletes: A systematic review.

OBJECTIVES: Identifying talented athletes from an early age to accelerate their development requires the investment of substantial resources. Due to the need for multifactorial approaches to talent identification, motor competence assessments are increasingly prevalent in contemporary testing batteries. Therefore, the aim of this review was to evaluate the literature on the use of a product-oriented motor competence assessment tool, the Körperkoordinationstest für Kinder (KTK) in the talent pathway and determine whether it is warranted in such programs. METHODS: Three electronic databases (i.e. PubMed, SPORTDiscus and Web of Science) were searched for studies that used at least one component of the KTK to assess motor competence for talent detection, identification, development and selection in athletic populations. A total of 21 articles were included in the review, of which seven used the full version of the KTK and 14 used modified versions or individual components of the battery. The quality of included studies was assessed using a modified version of the Joanna Brigg's Institute Critical Appraisal Checklist. RESULTS: The analysed literature suggests that the KTK can successfully distinguish between athletes of different competition levels and across different sporting domains, however, findings should be interpreted with caution due to the cross-sectional nature of the studies. Furthermore, the moving sideways subtest displayed the greatest discriminative power for athletes of different competition levels. Motor competence was not affected by maturation and did not differ between genders or playing positions. CONCLUSIONS: Collectively, these findings suggest that the KTK is a useful motor competence assessment in the talent pathway.

Assessing the potential of the qualitative trajectory calculus to detect gait pathologies: a case study of children with developmental coordination disorder.

The Qualitative Trajectory Calculus (QTC) is a qualitative spatio-temporal calculus for describing interactions between moving point objects. So far, it remained unclear whether QTC is useful for describing subtle differences, such as between the movements of different parts of a human body. We tested the applicability of QTC to detect differences in the gait patterns of children with or without Developmental Coordination Disorder (DCD). We found that using a combination of three markers (i.e. ankle, toe and trochanter), QTC can achieve a high classification accuracy (i.e. 83.3%) of classifying subjects correctly to either the DCD group or the control group.

Influence of M. tibialis anterior fatigue on the walk-to-run and run-to-walk transition in non-steady state locomotion.

The purpose of this study was to examine the influence of muscular fatigue of tibialis anterior (TA) on the walk-to-run transition (WRT) and run-to-walk transition (RWT) when speed is altered at different constant accelerations (a=0.01, 0.07 and 0.05 ms(-2)). Twenty women (height: 168.9+/-3.36 cm) performed WRTs and RWTs on a motor-driven treadmill, before and after a protocol inducing muscular fatigue of the TA. WRT-speed decreased after TA fatigue whereas RWT-speed did not change except during the intermediate deceleration. Integrated EMG (iEMG) of the activity burst of TA around heel contact was examined in the last steps before transition, the transition step and the first steps after transition. iEMG increased before WRT, then decreased after transition to running. In the RWT the opposite was observed: iEMG increased after RWT, then decreased with decreasing walking speed. After inducing fatigue in the TA, there was a decrease in iEMG in the WRT whereas no influence of fatigue was found on iEMG in the RWT. As a result of TA fatigue, WRT occurred at a lower speed, probably to avoid over-exertion of the TA. This indicates that the TA is a likely determinant of WRT as previously reported. The RWT, on the other hand, was not altered following TA fatigue, which would indicate that WRT and RWT are determined by different factors.