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There is some, albeit inconsistent, evidence supporting sex differences in preschoolers' motor competence (MC), with these observations not uniform when analyzed by age, and cultural groups. Thus, this study examined sex differences across ages in 3- to 5-year-old children's MC. A cross-country pooled sample of 6241 children aged 3-5 years (49.6% girls) was assessed for MC using the Test of Gross Motor Development-2nd/3rd edition, and children were categorized into groups of age in months. Multiple linear regression models and predictive margins were calculated to explore how sex and age in months affect scores of MC (i.e., locomotor and ball skills), with adjustments for country and BMI. The Chow's Test was used to test for the presence of a structural break in the data. Significant differences in favor of girls were seen at 57-59 and 66-68 months of age for locomotor skills; boys performed better in ball skills in all age periods, except for 42-44 and 45-47 months of age. The higher marginal effects were observed for the period between 45-47 and 48-50 months for locomotor skills (F = 30.21; and F = 25.90 for girls and boys, respectively), and ball skills (F = 19.01; and F = 42.11 for girls and boys, respectively). A significantly positive break point was seen at 45-47 months, highlighting the age interval where children's MC drastically improved. The identification of this breakpoint provides an evidence-based metric for when we might expect MC to rapidly increase, and an indicator of early delay when change does not occur at that age.
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Destreza Motora , Humanos , Destreza Motora/fisiología , Femenino , Masculino , Preescolar , Estudios Transversales , Factores Sexuales , Factores de Edad , Desarrollo Infantil/fisiología , Modelos LinealesRESUMEN
A person-centred approach was used to examine whether children with various actual and perceived motor competence (AMC and PMC) profiles differ in (enjoyment of) physical fitness (PF). The strength of the relationship between AMC and PMC was also assessed through aligned assessment tools. A sample of 287 7-11-year-old children (47.40% boys, Mage = 8.92 ± .78 years) was assessed on AMC with the KörperkoordinationsTest für Kinder (KTK3), and on PF with six validated fitness tests. Animated videos fully aligned with the AMC- and PF-tests were used to assess children's PMC and enjoyment of PF, respectively. Cluster analyses identified one convergent (i.e. high AMC-high PMC) and three partially convergent AMC-PMC profiles (i.e. low AMC-high PMC). Furthermore, children with relatively high AMC (i.e. high-average profile) reported higher PF (F = 30.99, p < .001), while children with relatively high PMC (i.e. average-high profile) reported higher enjoyment of PF (F = 9.02, p < .001). The correlation between AMC and PMC was significant but weak (r = .16). Overall, it seems important to invest in both children's AMC and PMC as they may support a higher (enjoyment of) PF, potentially leading to higher PA-levels.
When it comes to physical fitness, actual motor competence rather than perceived motor competence seemed to play the biggest role. As extra high perceived motor competence did not add additional benefits in terms of physical fitness, there might have been a ceiling effect of perceived motor competence.When looking at enjoyment of physical fitness, perceived motor competence seemed to be a more important factor than actual motor competence. However, profile analyses revealed that a relatively high perceived motor competence score may not fully compensate the loss of enjoyment in physical fitness when children's actual motor competence is relatively low.
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Destreza Motora , Aptitud Física , Placer , Humanos , Masculino , Niño , Destreza Motora/fisiología , Aptitud Física/fisiología , Femenino , Prueba de Esfuerzo/métodos , Percepción/fisiologíaRESUMEN
OBJECTIVES: (1) To develop reference values for health-related fitness in European children and adolescents aged 6-18 years that are the foundation for the web-based, open-access and multilanguage fitness platform (FitBack); (2) to provide comparisons across European countries. METHODS: This study builds on a previous large fitness reference study in European youth by (1) widening the age demographic, (2) identifying the most recent and representative country-level data and (3) including national data from existing fitness surveillance and monitoring systems. We used the Assessing Levels of PHysical Activity and fitness at population level (ALPHA) test battery as it comprises tests with the highest test-retest reliability, criterion/construct validity and health-related predictive validity: the 20 m shuttle run (cardiorespiratory fitness); handgrip strength and standing long jump (muscular strength); and body height, body mass, body mass index and waist circumference (anthropometry). Percentile values were obtained using the generalised additive models for location, scale and shape method. RESULTS: A total of 7 966 693 test results from 34 countries (106 datasets) were used to develop sex-specific and age-specific percentile values. In addition, country-level rankings based on mean percentiles are provided for each fitness test, as well as an overall fitness ranking. Finally, an interactive fitness platform, including individual and group reporting and European fitness maps, is provided and freely available online (www.fitbackeurope.eu). CONCLUSION: This study discusses the major implications of fitness assessment in youth from health, educational and sport perspectives, and how the FitBack reference values and interactive web-based platform contribute to it. Fitness testing can be conducted in school and/or sport settings, and the interpreted results be integrated in the healthcare systems across Europe.
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Fuerza de la Mano , Aptitud Física , Masculino , Femenino , Humanos , Adolescente , Niño , Valores de Referencia , Reproducibilidad de los Resultados , Ejercicio Físico , Prueba de Esfuerzo/métodos , Índice de Masa CorporalRESUMEN
Well-designed talent programmes in sports with a focus on talent identification, orientation, development, and transfer support the engagement of young individuals and the pursuit of elite performance. To facilitate these processes, an analysis of task, environmental and individual characteristics per sport is much needed. The aims of this study were to 1) analyse whether unique profiles per sport could be established by generic characteristics and 2) to discuss similarities and differences for the potential application in talent development and transfer. By means of a validated survey, 1247 coaches from 34 sports ranked 18 characteristics on importance to their sports (0 = not important - 10 = very important). To discriminate the responses per sport a Discriminant Analysis (DA) was carried out. To refine the DA-classification, Uniform Manifold Approximation and Projection (UMAP) with CatBoost classifier was performed. To test the performance of the CatBoost classifier-algorithm, a confusion-matrix was generated. The cross-validated DA showed that 70.2% of the coaches were correctly classified to their sport. The UMAP/CatBoost technique revealed 75.1% accuracy with correctly predicted responses per sport ranging from 18.2% (sailing) to 98.2% (soccer). With varying precision, the algorithm was able to differentiate sports by importance of its characteristics indicating similarities and differences per sport.
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ABSTRACT: Mireille, M, Johan, P, Matthieu, L, and Pieter, V. A retrospective analysis of the national youth teams in volleyball: Were they always faster, taller, and stronger? J Strength Cond Res 36(9): 2615-2621, 2022-Although there are numerous studies comparing the characteristics of young and adult volleyball players of different levels, it remains unclear to what extent these findings can be used for performance prediction because very few are based on longitudinal or retrospective analyses. The aim of the current retrospective study was to test to what extent anthropometry, physical performance, and motor coordination can predict future selection in national youth teams. From 2012 to 2015, 1738 10- to 13-year-old boys and girls who played volleyball completed 3 anthropometric, 4 physical performance, and 3 motor coordination tests. In January 2020, 52 athletes of this sample were found to be part of one of the national youth teams of Belgium. A multivariate analysis of covariance, discriminant analyses, and logistic regression analyses were conducted to compare the test results of the selected vs. the nonselected players. Significance level was set at p ≤ 0.05. Results showed that the selected players were already taller and showed better jumping performance, and for females, they tended to have better motor coordination at the time of baseline measurement. Therefore, it seems important to focus on the development of motor coordination and jumping performance at young ages because superiority in these characteristics increases the chances to be selected for the national team 4-8 years later. Nevertheless, considering the large variation in results, selection cannot be made based on these characteristics alone. The practical implications for coaches and federations with respect to training and talent detection are discussed.
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Rendimiento Atlético , Voleibol , Adolescente , Adulto , Antropometría , Atletas , Niño , Preescolar , Femenino , Humanos , Masculino , Estudios RetrospectivosRESUMEN
Whereas it has been shown that listening to music impairs the detection of auditory and visual signals, it is unclear to what extent music affects a cyclist's ability to detect and interpret hazardous traffic situations. In the current experiment, thirty-seven participants carried out a hazard perception test for cyclists. Participants were divided into three groups: control, passive, or active. The control group did the test without hearing music. The passive and active group did hear music, yet the passive group was asked to ignore the music, while the active group was asked to pay attention to the lyrics. Results showed no differences in reaction rate, reaction time, or gaze behaviour between any of the groups. These findings temper the existing safety concerns about the negative effect of music on traffic safety. Nevertheless, music might still have consequences under certain conditions or in certain risk-groups such as children. Practitioner summary: It is unclear how music affects traffic safety. The current experiment tested to what extent hazard perception was affected by listening actively or passively to music. Under the current experimental conditions, listening to music was found to have no effect on hazard perception. Abbreviation: NHTSA: national highway traffic safety administration; AOI: area of interest; TTFS: time to first saccade; FFD: first fixation duration.
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Música , Percepción Auditiva , Niño , Humanos , Factores de RiesgoRESUMEN
The aim of the study was to identify benchmarks for anthropometric, physical performance, motor coordination, and psychological characteristics by comparing youth badminton players of different levels through the use of a multifactorial test battery. Sixty-one male participants aged 12-18 years were divided into three groups: elite (N = 10), sub-elite (N = 24), and novice (N = 27). Standard test batteries for anthropometry (including measures to estimate biological maturity), physical performance, and motor coordination were applied, as well as the modified PCDEQ2 questionnaire for psychological characteristics of youth athletes (Hill, 2016). Multivariate analyses of covariance (MANCOVAs) with age and biological maturity as covariates were used to investigate differences between skill levels. A discriminant analysis was used to reveal to what extent participants could be correctly assigned to their skill group. Significant differences were found in physical performance (explosive power, flexibility, speed, and endurance), BMI and motor coordination. In the psychological domain, perfectionism was found to be significantly different and elites scored highest. The discriminant analysis showed that 100% of the participants were correctly classified and 80.0% were correctly cross validated. These results significantly add to the previously limited youth players' reference values, and confirm the value of a generic, i.e. without sport-specific testing, multifactorial approach to talent identification in youth badminton.
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The aim of this study was (1) to examine the long-term effectiveness of the "Multimove for Kids" program, a 30-week fundamental motor skill intervention (approximately 1 hour per week) for typically developing children between 3 and 8 years, and (2) to determine the influence of participation in organized sports on motor competence (MC) six years after the intervention. Of the 992 children who took part in the "Multimove" program, 399 (intervention group: N = 228, control group: N = 171) were tested again at 6-year follow-up. MC was measured with the Test of Gross Motor Development, 2nd Edition. To examine the long-term impact of "Multimove" on MC, and the effect of participation in organized sports a latent growth curve analysis was conducted. After the 30-week intervention, the intervention group outperformed the control group (ß = 5.57, P < .001). However, when the entire study period, including the 6-year follow-up, was considered, the intervention group made less progress in MC than the control group (ß = -0.41, P < .05). Looking at the engagement in organized sports, it was found that years of experience before the intervention had no significant influence on the evolution of MC over time, whereas a positive effect was observed for children's average sports participation (h/week) during the 6-year retention period (ß = 0.14, P < .001). Finally, children practicing predominantly object control-oriented sports during retention obtained slightly better MC scores at follow-up (ß = 0.01, P < .01). The "Multimove" intervention does not have a long-term effect on the development of MC. However, participation in organized sports has a positive influence on MC evolution over time.
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Destreza Motora/fisiología , Educación y Entrenamiento Físico/métodos , Deportes Juveniles/fisiología , Bélgica , Niño , Desarrollo Infantil/fisiología , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Evaluación de Programas y Proyectos de Salud , Factores SexualesRESUMEN
SIGNIFICANCE: Experts in different sports show superior decision-making skills compared with novices, but little is known about its development in youth players. This study shows that the age-related improvements in visual cognition and accumulation of sport-specific experience explain a considerable amount of the development in decision making in volleyball. PURPOSE: The aim of this study was to investigate the mediating effects of visual cognition and volleyball experience on the relationship between age and decision making in youth volleyball players. METHODS: A total of 171 female volleyball players aged 6 to 17 years performed a sport-specific, video-based test of decision making, as well as four different visual cognition tests. Using structural equation modeling, we examined if volleyball experience and a latent variable constructed from the four tests of visual cognition act as parallel mediators in the association between age and decision making. RESULTS: The parallel multiple mediation model for the association between age and decision making was supported in youth volleyball players. Moreover, significant indirect effects and a nonsignificant direct effect indicated that visual cognition and experience fully mediated the relation between age and decision making and together explain 38% of the variance in decision-making performance. The effects of both mediators were not significantly different, and there was no residual correlation between experience and visual cognition, which indicates that these mediators are unrelated to each other. CONCLUSIONS: Our findings demonstrate that visual cognition and volleyball experience mediate the relation between age and decision making independently, which indicates that they each influence different parts of the decision-making process. These results highlight the importance of the development of perceptual-cognitive skill in young players, and future research should further investigate the development of these skills as well as their underlying factors in different kinds of sports.
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Rendimiento Atlético , Voleibol , Adolescente , Cognición , Toma de Decisiones , Femenino , HumanosRESUMEN
During the first half of the 20th century, extraordinary high jumping performances of East-African athletes were observed. These athletes used a specific native jumping style called Gusimbuka Urukiramende. Eye-witnesses believed that these performances could have been world-records and that these athletes could have competed at the Olympics. However, these athletes never participated in international competitions and there is no other proof to support these performance claims. We have analysed historical photos and cine sequences of these jumps, documented the movement analysis of this technique, quantified performance and compared it to contemporaneous elite performances. Our analyses demonstrate that Gusimbuka Urukiramende athletes did not jump as high as the world record. Nevertheless, even though they used a suboptimal jump technique (because they had to lift their bodies higher to cross the bar) they could cross bar heights of 188 cm or 106% body height and as such their performance still was worthy of participation to the Olympics.
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Rendimiento Atlético/fisiología , Atletismo/fisiología , África Oriental , Rendimiento Atlético/historia , Población Negra/historia , Historia del Siglo XX , Humanos , Masculino , Análisis y Desempeño de Tareas , Atletismo/historiaRESUMEN
In many sports, elite players outperform novices on tests for perceptual-cognitive skills, such as anticipation, decision-making and pattern recall. However, the developmental trajectory of these perceptual-cognitive skills has received limited attention. Therefore, this study examined the development of anticipation, decision-making and pattern recall in 202 female volleyball players aged between 7 and 26 years old. Participants were categorized into six age groups: U9, U11, U13, U15, U17 and Seniors. Using a video-based occlusion protocol, we assessed participants' ability to predict pass direction, decide the most optimal attack zone, or recall the opponents' defence positions. The results demonstrated that U17 and adult players had superior accuracy and shorter response times than younger players on all three tests. Notably, U9 players performed worse than older players on all tests. Binomial distributions showed that decision-making was above chance for U17 players and adults, whereas anticipation was above chance for almost all players. Our findings indicate that age-related improvements of perceptual-cognitive skills are evident at 11 years old. However, decision-making seems to develop considerably later than anticipation and pattern recall, suggesting different developmental trajectories for the different perceptual-cognitive skills. Longitudinal research regarding the development of perceptual-cognitive skills and their underlying mechanisms is warranted, as this could have important implications for talent detection and development.
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Rendimiento Atlético/psicología , Cognición , Percepción Visual , Voleibol/psicología , Adolescente , Adulto , Factores de Edad , Anticipación Psicológica , Atletas , Niño , Estudios Transversales , Femenino , Humanos , Recuerdo Mental , Adulto JovenRESUMEN
The present study aimed to examine differences in motor competence (MC) in children aged 6-9 years old in northern, central, and southern European regions using the Körperkoordinationstest für Kinder (KTK). The secondary aim of the study was to examine interactions between region and children's age, sex, and weight status (determined as healthy weight or overweight/obese). Data were pooled from independent studies conducted in Finland (mean age 7.81 ± 1.19 years, n = 690), Belgium (mean age 8.25 ± 1.09 years, n = 1896), and Portugal (mean age 8.31 ± 1.02 years, n = 758) between 2008 and 2016. Cross-cultural differences in MC and interaction effects were tested using ANOVAs and ANCOVAs. Age, sex, and BMI percentile were used as covariates. Geographical region significantly explained 19% of the variance in MC, while BMI (5%), sex (3%), and age (0.3%) were significant covariates. The interaction effect of region and age (5%), region and sex (0.6%), and region and BMI (0.2%) on MC was also significant. Cross-cultural differences in children's MC increased substantially across age, independent of weight status. Girls slightly underperformed in MC compared to boys in regions where the overall level of MC was lower. Interestingly, the association between body weight status and MC was relatively consistent across the regions. Future cross-cultural studies should further explore the influence of individual (eg, physical activity) and environmental (eg, physical activity and sport policy) factors on MC development.
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Índice de Masa Corporal , Comparación Transcultural , Destreza Motora , Bélgica , Peso Corporal , Niño , Femenino , Finlandia , Humanos , Masculino , PortugalRESUMEN
BACKGROUND: Equations predicting age at peak height velocity (APHV) are often used to assess somatic maturity and to adjust training load accordingly. However, information on the intra-individual accuracy of APHV in youth athletes is not available. AIM: The purpose of this study is to assess the accuracy of predication equations for the estimation of APHV in individual youth male football players. SUBJECTS AND METHODS: Body dimensions were measured at least every three months in 17 elite youth male football players (11.9 ± 0.8 years at baseline) from the 2008-2009 through the 2011-2012 seasons. APHV was predicted at each observation with four suggested equations. Predicted APHV was compared to the player's observed APHV using one-sample-t-tests and equivalence-tests. Longitudinal stability was assessed by comparing the linear coefficient of the deviation to zero. RESULTS: Predicted APHV was equivalent to the observed APHV in none of the players. A difference with a large effect size (Cohen's d > 0.8) was noted in 87% of the predictions. Moreover, predictions were not stable over time in 71% of the cases. CONCLUSIONS: None of the evaluated prediction equations is accurate for estimating APHV in individual players nor are predictions stable over time, which limits their utility for adjusting training programmes.
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Desarrollo del Adolescente , Antropometría/métodos , Desarrollo Infantil , Fútbol , Deportes Juveniles , Adolescente , Niño , Humanos , Masculino , Modelos Teóricos , Maduración SexualRESUMEN
A method is presented for detecting changes in the axial peak tibial acceleration while adapting to self-discovered lower-impact running. Ten runners with high peak tibial acceleration were equipped with a wearable auditory biofeedback system. They ran on an athletic track without and with real-time auditory biofeedback at the instructed speed of 3.2 m·s-1. Because inter-subject variation may underline the importance of individualized retraining, a change-point analysis was used for each subject. The tuned change-point application detected major and subtle changes in the time series. No changes were found in the no-biofeedback condition. In the biofeedback condition, a first change in the axial peak tibial acceleration occurred on average after 309 running gait cycles (3'40"). The major change was a mean reduction of 2.45 g which occurred after 699 running gait cycles (8'04") in this group. The time needed to achieve the major reduction varied considerably between subjects. Because of the individualized approach to gait retraining and its relatively quick response due to a strong sensorimotor coupling, we want to highlight the potential of a stand-alone biofeedback system that provides real-time, continuous, and auditory feedback in response to the axial peak tibial acceleration for lower-impact running.
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Fenómenos Biomecánicos/fisiología , Marcha/fisiología , Carrera/fisiología , Tibia/fisiología , Aceleración , Acelerometría , Adulto , Femenino , Humanos , MasculinoRESUMEN
This study evaluated the effect of a multidisciplinary treatment program for children with obesity (OB) on motor competence, executive functioning (EF), and brain structure. Nineteen children with OB (7-11 years), who attended a multidisciplinary treatment program consisting of diet restriction, cognitive behavioral therapy, and physical activity, were compared with an age-matched control group of 24 children with a healthy weight (HW), who did not follow any treatment. For both groups, anthropometric measurements and tests of motor competence and EF were administered twice, with 5 months between pretest and posttest. Additionally, children's brain structure was assessed by performing a magnetic resonance imaging (MRI) scan at the pretest and posttest, which included a T1 anatomical scan, diffusion MRI scan, and magnetization transfer imaging scan. Compared to HW controls, children with OB lost a considerable amount of their body mass (p ≤ .001) and significantly improved their balance skills (p ≤ .001), while no transfer effects of the program were observed for EF. Furthermore, the program resulted in a significant increase in total (p ≤ .001) and cerebellar (p ≤ .001) gray matter volume in children with OB, while no change was observed in the HW controls. Finally, only weak to moderate (nonsignificant) correlations could be observed between structural brain alterations, weight-related changes, and behavioral improvements. Altogether, this is the first longitudinal study showing behavioral and structural brain alterations in response to a multidisciplinary weight loss program for children with OB. Our findings support the need for multidimensional intervention (and prevention) measures for children with OB to deal with this multifactorial health problem.
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Función Ejecutiva/fisiología , Sustancia Gris/anatomía & histología , Destreza Motora/fisiología , Plasticidad Neuronal/fisiología , Obesidad Infantil/fisiopatología , Obesidad Infantil/terapia , Pérdida de Peso/fisiología , Programas de Reducción de Peso , Niño , Femenino , Sustancia Gris/diagnóstico por imagen , Humanos , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Resultado del TratamientoRESUMEN
BACKGROUND: Previous studies suggest that obesity (OB) is associated with disrupted brain network organization; however, it remains unclear whether these differences already exist during childhood. Moreover, it should be investigated whether deviant network organization may be susceptible to treatment. METHODS: Here, we compared the structural connectomes of children with OB with age-matched healthy weight (HW) controls (aged 7-11 years). In addition, we examined the effect of a multidisciplinary treatment program, consisting of diet restriction, cognitive behavioral therapy, and physical activity for children with OB on brain network organization. After stringent quality assessment criteria, 40 (18 OB, 22 HW) data sets of the total sample of 51 participants (25 OB, 26 HW) were included in further analyses. For all participants, anthropometric measurements were administered twice, with a 5-month interval between pre- and post tests. Pre- and post T1- and diffusion-weighted imaging scans were also acquired and analyzed using a graph-theoretical approach and network-based statistics. RESULTS: Global network analyses revealed a significantly increased normalized clustering coefficient and small-worldness in children with OB compared with HW controls. In addition, regional analyses revealed increased betweenness centrality, reduced clustering coefficient, and increased structural network strength in children with OB, mainly in the motor cortex and reward network. Importantly, children with OB lost a considerable amount of their body mass after the treatment; however, no changes were observed in the organization of their brain networks. CONCLUSION: This is the first study showing disrupted structural connectomes of children with OB, especially in the motor and reward network. These results provide new insights into the pathophysiology underlying childhood obesity. The treatment did result in a significant weight loss, which was however not associated with alterations in the brain networks. These findings call for larger samples to examine the impact of short-term and long-term weight loss (treatment) on children's brain network organization.
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Encéfalo , Conectoma/métodos , Obesidad Infantil , Pérdida de Peso/fisiología , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Niño , Imagen de Difusión por Resonancia Magnética , Femenino , Humanos , Masculino , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiología , Obesidad Infantil/diagnóstico por imagen , Obesidad Infantil/fisiopatología , Obesidad Infantil/terapiaRESUMEN
PURPOSE: Motor assessments generally produce a single motor competence score based on the general motor ability hypothesis, which states that motor competence is a one-dimensional trait underlying a wide range of motor skills. Yet, it is unclear whether the general motor ability hypothesis holds true in middle childhood, which is marked by an increased participation in sports and other types of physical activity. Therefore, the aim of the study was to evaluate the structure of motor competence in middle childhood using a test battery with a large item set. METHOD: A cross-sectional design was used to collect motor competence data of 2538 children aged 6-11 years. Participants completed the Bruininks-Oseretsky Test of Motor Proficiency-2nd Edition Short Form (BOT-2 SF), which consists of 14 skill items and covers different motor domains. In accordance with the BOT-2 SF manual, point scores were computed for each item. Polytomous Rasch analyses (ie, general partial credit model) were carried out to investigate the construct of motor competence. RESULTS: Rasch analyses revealed different items with unordered threshold parameters, due to ceiling effects. However, after empirically rescaling the category width for each item, follow-up analyses revealed a one-dimensional structure with 12 items. CONCLUSION: The study provides some evidence of a one-dimensional construct (ie, motor competence) underlying motor assessment in middle childhood. Continued efforts should be made to ensure that valid composite scores are used in motor assessment and to better understand the development of motor competence across childhood and into adolescence and adulthood.
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Destreza Motora , Bélgica , Niño , Estudios Transversales , Prueba de Esfuerzo , Humanos , Reproducibilidad de los ResultadosRESUMEN
This study investigated differences in generic and soccer specific motor coordination, as well as speed and agility depending on age and maturity in elite youth soccer players (U10-U15, N = 619). Measurements included body height, body weight and sitting height to estimate age at peak height velocity (APHV); three Körperkoordinationstest für Kinder subtests (i.e. jumping sideways (JS), moving sideways (MS), balancing backwards (BB)) to assess generic motor coordination; the UGent dribbling test for soccer specific motor coordination; a 5m/30m sprint and T-test for speed and agility, respectively. Age specific z-scores of the predicted APHV identified players as earlier, on time or later maturing. (M)ANOVA analyses showed significant age by maturity interaction effects for the speed and agility test cluster, revealing maturity related differences in U14 and U15 players. Next to an overall higher performance with age for all test clusters (η2 0.080-0.468), earlier maturing players outperformed their later maturing peers in 5m/30m sprinting. The opposite was seen for JS and BB. So, players' maturity status should be taken into account to adequately value performance in talent identification. Also, the focus on characteristics that appear to be minimally biased by an earlier maturational timing (i.e. motor coordination) should be increased.
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Factores de Edad , Destreza Motora/fisiología , Maduración Sexual , Fútbol/fisiología , Adolescente , Aptitud/fisiología , Estatura , Peso Corporal , Humanos , MasculinoRESUMEN
This study aimed to examine longitudinal changes in isometric strength of the knee extensors (ImKE) and knee flexors (ImKF) at 30° and 60°. The sample was composed of 67 players aged 11.0-13.9 years at baseline over five years. Stature, body mass, skinfolds, and isometric strength (ImKE30°, ImKF30°, ImKE60° and ImKF60°) were measured. Fat mass and fat-free mass (FFM) were derived from skinfolds. Skeletal age was obtained using TW2 RUS. Multilevel random effects regression analyses extracted developmental polynomial models. An annual increment on chronological age (CA) corresponded to 5.6 N (ImKE30°: ), 2.7 N (ImKF30°: ), 4.6 N (ImKE60°: ) and 1.5 N (ImKF60°). An increment of 1 kg in FFM predicted isometric strength as follows: 1.2 N (ImKE30°), 2.1 N (ImKF30°), 3.1 N (ImKE60°) and 2.0 N (ImKF60°). The following equations were obtained: ImKE30°=5.759×CA+1.163×FFM; ImKF30°=-19.369+2.691×CA+0.693×CA2+2.108×FFM; ImKE60°=4.553×CA+3.134×FFM; and, ImKF60°=-19.669+1.544×CA+2.033×FFM. Although skeletal maturity had a negligible effect on dependent variables, age and body size, based on FFM, were relevant longitudinal predictors. During adolescence, systematic assessment of knee extensors and knee flexors are strongly recommended to prevent impairment of knee muscle groups.
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Desarrollo del Adolescente/fisiología , Rodilla/fisiología , Fuerza Muscular/fisiología , Fútbol/fisiología , Adolescente , Determinación de la Edad por el Esqueleto , Factores de Edad , Distribución de la Grasa Corporal , Estatura , Índice de Masa Corporal , Niño , Humanos , Contracción Isométrica , Estudios Longitudinales , Dinamómetro de Fuerza Muscular , Músculo Esquelético/crecimiento & desarrollo , Músculo Esquelético/fisiología , Grosor de los Pliegues CutáneosRESUMEN
PURPOSE: This study aimed to improve the prediction accuracy of age at peak height velocity (APHV) from anthropometric assessment using nonlinear models and a maturity ratio rather than a maturity offset. METHODS: The dataset used to develop the original prediction equations was used to test a new prediction model, utilizing the maturity ratio and a polynomial prediction equation. This model was then applied to a sample of male youth academy soccer players (n = 1330) to validate the new model in youth athletes. RESULTS: A new equation was developed to estimate APHV more accurately than the original model (new model: Akaike information criterion: -6062.1, R2 = 90.82%; original model: Akaike information criterion = 3048.7, R2 = 88.88%) within a general population of boys, particularly with relatively high/low APHVs. This study has also highlighted the successful application of the new model to estimate APHV using anthropometric variables in youth athletes, thereby supporting the use of this model in sports talent identification and development. CONCLUSION: This study argues that this newly developed equation should become standard practice for the estimation of maturity from anthropometric variables in boys from both a general and an athletic population.