Associated ACL risk factors differences during an unanticipated volleyball blocking movement     

David Zahradnik  Daniel Jandacka  Gabriela Beinhauerova  Joseph Hamill 《Journal of sports sciences》2020,38(20):2367-2373

ABSTRACT

The lateral tilt of the arms accompanied by trunk lateral tilt is a typical blocking manoeuvre in volleyball. However, during this unanticipated blocking movement, an associated risk of ACL injury may result. The aim of the present study was to compare associative ACL risk factors at the initial contact and the first and second peak of VGRF during an unanticipated blocking movement with different arm positions. Synchronized kinematic and kinetic data were collected for each trial of each condition. Student paired t-tests and effect size were used to determine differences between two conditions (S – with arms straight up from the body) and (T – with the arms and trunk laterally tilted). The results showed that the T condition significantly decreases knee flexion, increases VGRF at the foot contact, first peak force and increases the valgus moment at the first peak force. The values of the associated risk factors for a non-contact ACL injury appear to be related to the tilted arm position accompanied by trunk tilt towards to right lower limb during landing. The players should be taught to land with greater knee flexion and, if possible, a double-leg landing to decrease right lower limb loading during the blocking manoeuvre.  相似文献   

A Developmental Study of the Self-Prioritization Effect in Children Between 6 and 10 Years of Age     

Hélène Maire  Renaud Brochard  Daniel Zagar 《Child development》2020,91(3):694-704

Self-biases are well described in adults but remain poorly understood in children. Here, we investigated in 6–10 year-old children (N = 132) the self-prioritization effect (SPE), a self-bias which reflects, in adults, the perceptual advantage for stimuli arbitrarily associated with the self as compared to those associated with other persons. We designed a child-friendly adaptation of a paradigm originally introduced in adults by Sui, He, and Humphreys (2012) in order to test whether the SPE also occurs in children and if so, to determine its evolution with age. A robust SPE was obtained from the age of 6, and this effect was similar-sized in our four age groups. These findings are discussed with reference to the development of the self during childhood.  相似文献   

Effects of plyometric jump training in female soccer player’s vertical jump height: A systematic review with meta-analysis     

Rodrigo Ramirez-Campillo  Javier Sanchez-Sanchez  Blanca Romero-Moraleda  Javier Yanci  Antonio García-Hermoso  Filipe Manuel Clemente 《Journal of sports sciences》2020,38(13):1475-1487

ABSTRACT

To assess the effects of plyometric jump training (PJT) in female soccer player’s vertical jump height, a review was conducted using the data sources PubMed, MEDLINE, Web Of Science and SCOPUS. Only peer-review articles were included. To qualify for inclusion in the meta-analysis, studies must have included (i) a PJT programme of at least 2 weeks, (ii) cohorts of healthy female soccer players with no restriction for age, (iii) a control group, (iv) a measure of countermovement jump (CMJ). The inverse variance random-effects model for meta-analyses was used. From 7,136 records initially identified through database searching, 8 were eligible for meta-analysis, comprising 9 training groups (n = 99) and 9 control groups (n = 94). The magnitude of the main effect was moderate (ES = 1.01 [95%CI = 0.36–1.66], Z = 3.04, p = 0.002). Sub-group analyses were performed (i.e., PJT frequency, duration and total number of sessions), revealing no significant subgroup differences (p = 0.34–0.96). Among the studies included in this review, none reported injury or other adverse effects. In conclusion, PJT is effective in female soccer players for the improvement of vertical jump height. In future, research must identify specific dose–response relationships following PJT, particularly in the long term.  相似文献   

Fitness,physical activity and academic achievement in overweight/obese children     

Cristina Cadenas-Sanchez  Jairo H. Migueles  Irene Esteban-Cornejo  Jose Mora-Gonzalez  Pontus Henriksson  María Rodriguez-Ayllon 《Journal of sports sciences》2020,38(7):731-740

ABSTRACT

The aim of this study was to examine the associations of fitness and physical activity with academic achievement in children with overweight/obesity. A total of 106 (10.0 ± 1.1y, 61 boys) children participated. The fitness components were assessed by field and laboratory-based tests. Physical activity was measured via accelerometry. The academic achievement was assessed by a standardised test and school-grades. Field-based cardiorespiratory fitness was associated with language skills (ß-standardised- ranging from 0.281 to 0.365, p < 0.01). The field-based muscular strength was associated with grade point average, natural and social sciences, and foreign language (ß = 0.280–0.326, all p ≤ 0.01). Speed-agility was associated with some language-related skills (ß = 0.325–0.393, all p ≤ 0.01). The laboratory-based muscular strength also showed an association with mathematics skills (ß = 0.251–0.306, all p ≤ 0.01). Physical activity did not show significant association with academic achievement (p > 0.01). Overall, the significant associations observed for muscular strength and speed/agility were attenuated and disappeared in many cases after additional adjustments for body mass index and cardiorespiratory fitness, indicating that these associations are inter-dependent. Our study contributes by indicating that other fitness components apart from cardiorespiratory fitness, such as muscular strength and speed-agility, are positively associated with academic achievement. However, these associations appear to be dependent on body mass index and cardiorespiratory fitness.  相似文献   

The Tuscarora War: Indians,Settlers, and the Fight for the Carolina Colonies David La Vere. Chapel Hill: University of North Carolina Press, 2013.     

Daniel P. Murphy 《Journal of American culture (Malden, Mass. : 2003)》2014,37(4):439-440

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Development of perfectionism in junior athletes: Examination of actual and perceived parental perfectionism     

Luke F. Olsson  Andrew P. Hill  Daniel J. Madigan  George Woodley 《Journal of sports sciences》2020,38(6):669-675

ABSTRACT

Initial research suggests that parental perfectionism is central to the development of athlete perfectionism. However, it is unclear whether perceived or actual parental perfectionism is most important. The present study aimed to address this issue in two ways. First, we re-examined the predictive ability of actual versus perceived parental perfectionism on athlete perfectionism. Second, for the first time, we tested whether perceived parental perfectionism mediated the relationship between actual parental perfectionism and athlete perfectionism. A sample of 150 junior athletes and their parents completed measures of perfectionism (perfectionistic strivings and perfectionistic concerns). Junior athletes completed two measures, one of their own perfectionism and one of perceptions of their parents’ perfectionism. Parents completed one measure of their own perfectionism. Regression analyses showed that perceived parental perfectionism predicted athlete perfectionism over and above actual parental perfectionism. Mediation analyses provided support for our proposed model. Overall, the findings suggest that both actual and perceived parental perfectionism are important in the development of perfectionism in junior athletes.  相似文献   

The emergence of a paradigm in the curriculum field: A reply to Jickling     

Daniel Tanner  Laurel N. Tanner 《Interchange》1988,19(2):50-58

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Why we need literary translation now     

Daniel Simon 《Publishing Research Quarterly》2003,19(3):48-51

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Piaget and school education: A socio-cultural challenge     

Eduardo Martí 《Prospects》1996,26(1):141-158

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Book review     

Daniel L. Stufflebeam 《Educational Assessment, Evaluation and Accountability》1992,5(3):321-325

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