Effect of postural changes on 3D joint angular velocity during starting block phase

Abstract

Few studies have focused on the effect of posture during sprint start. The aim of this study was to measure the effect of the modification of horizontal distance between the blocks during sprint start on three dimensional (3D) joint angular velocity. Nine trained sprinters started using three different starting positions (bunched, medium and elongated). They were equipped with 63 passive reflective markers, and an opto-electronic Motion Analysis® system was used to collect the 3D marker trajectories. During the pushing phase on the blocks, norm of the joint angular velocity (NJAV), 3D Euler angular velocity (EAV) and pushing time on the blocks were calculated. The results demonstrated that the decrease of the block spacing induces an opposite effect on the angular velocity of joints of the lower and the upper limbs. The NJAV of the upper limbs is greater in the bunched start, whereas the NJAV of the lower limbs is smaller. The modifications of NJAV were due to a combination of the movement of the joints in the different degrees of freedom. The medium start seems to be the best compromise because it leads, in a short pushing time, to a combination of optimal joint velocities for upper and lower segments.     

A Flexible Latent Class Approach to Estimating Test‐Score Reliability

The latent class reliability coefficient (LCRC) is improved by using the divisive latent class model instead of the unrestricted latent class model. This results in the divisive latent class reliability coefficient (DLCRC), which unlike LCRC avoids making subjective decisions about the best solution and thus avoids judgment error. A computational study using large numbers of items shows that DLCRC also is faster than LCRC and fast enough for practical purposes. Speed and objectivity render DLCRC superior to LCRC. A decisive feature of DLCRC is that it aims at closely approximating the multivariate distribution of item scores, which might render the method suited when test data are multidimensional. A simulation study focusing on multidimensionality shows that DLCRC in general has little bias relative to the true reliability and is relatively accurate compared to LCRC and classical lower bound methods coefficients α and λ2 and the greatest lower bound.     

A positive psychological viewpoint for success at school – 10 characteristic strengths of the Finnish high-achieving students

People who exploit their strengths flourish; they are not only engaged with their goals, but also to their well-being and the content of life. In this study, interest focused on the high-achieving students in the Finnish general upper secondary education, in other words, on straight-A graduates’ characteristic strengths. This was a narrative study in which the data were obtained through written narratives and narrative interviews among 14 Finnish straight-A graduates. The data were analyzed with narrative analyzing methods. Ten typical strengths found and further categorized into three key dimensions were: (1) the thirst of knowledge and passion for learning, (2) fortitude and authenticity, and (3) love. This study implied that the youth’s school paths and well-being actively increased their own characteristic strengths.     

A neurodevelopmental profile of the rural hearing‐impaired child in the QwaQwa region,South Africa

Being hearing impaired does not only affect a child's academic performance, but can also influence a child's overall development and ability to succeed academically. Children with hearing impairment often experience delays in other areas of their development and an understanding of the inter‐relatedness of these delays are important in order to address all these aspects, and thus minimise the impact on a child's overall development. The paper provides a neurodevelopmental profile of 4‐year‐old to 8‐year‐old rural hearing‐impaired children based on the result of a psychometric assessment. Eighteen children were selected from a special needs school in the rural QwaQwa Free State area of South Africa and underwent a psychometric assessment using two test batteries (Griffiths mental developmental scales – extended revised and a neurodevelopmental evaluation scale). The neurodevelopmental profile will contribute to knowledge of the nature of the challenges faced by the hearing‐impaired child in rural education and the neurodevelopmental origin of these challenges.     

Validation of the Early Childhood Ecology Scale-Revised: A Reflective Tool for Teacher Candidates

Given increasing numbers of young culturally and/or linguistically diverse (CLD) children across the United States, it is crucial to prepare early childhood teachers to create high-quality environments that facilitate the development of all children. The Early Childhood Ecology Scale-Revised (ECES-R) has been developed as a reflective tool to help early childhood teacher candidates examine their beliefs concerning classroom ecology. Using cultural responsivity and classroom management theories as the theoretical framework, the authors posit that the ECES-R identifies five dimensions that promote a high-quality, culturally responsive classroom ecology. These include the sociocognitive, sociocultural, sociolinguistic, socioemotional, and sociophysical dimensions. Evidence for reliability and validity was established. Factor analysis supported the five proposed dimensions, with the identification of an additional dimension: sociocomfort.     

Stress,Anxiety, and School Burnout Post COVID-19: A Study of French Adolescents

This study examined the symptoms of exhaustion, school stress and anxious school refusal from a comparative developmental perspective in French adolescents enrolled in public and private general, technological and vocational schools. It is particularly important to consider academic stress levels, anxiety and school burnout in middle and high school students as they are linked to many mental health problems, such as depression or suicidal thoughts. In this study, four hundred and ninety-three adolescents completed an online questionnaire consisting of the School Burnout Inventory, the Echelle Toulousaine de Stress Scolaire perçu and the School refusal evaluation was developed. The results show a very high percentage of suffering among teenagers. The young people most affected are high school students and more particularly students in 10th and 12th grade, with nearly three-quarters of them suffering from school burnout and/or high school stress, without any distinction between the sexes or the type of schooling.     

Accuracy of a screening instrument to identify potential child abuse in emergency departments

Although screening for child abuse at emergency departments (EDs) increases the detection rate of potential child abuse, an accurate instrument is lacking. This study was designed to measure the accuracy of a screening instrument for detection of potential child abuse used in EDs. In a prospective cohort study at three Dutch EDs, a 6-item screening instrument for child abuse, Escape, was completed for each child visiting the ED. The data from the completed Escape instrument was used to calculate sensitivity, specificity, and the positive/negative predictive value per item. The clinical notes and conclusions of the screen instruments of all potentially abused children reported to the hospitals’ Child Abuse Teams were collected and reviewed by an expert panel. A logistic regression model was used to evaluate the predictors of potential abuse. Completed Escape instruments were available for 18,275 ED visits. Forty-four of the 420 children with a positive screening result, and 11 of the 17,855 children with a negative result were identified as potentially abused. Sensitivity of the Escape instrument was 0.80 and specificity was 0.98. Univariate logistic regression showed that potentially abused children were significantly more likely to have had an aberrant answer to at least one of the items, OR = 189.8, 95% CI [97.3, 370.4]. Most of the children at high risk for child abuse were detected through screening. The Escape instrument is a useful tool for ED staff to support the identification of those at high risk for child abuse.     

Relationships among training stress,mood and dehydroepiandrosterone sulphate/cortisol ratio in female cyclists

Abstract

In this study, we examined the effect of rapidly increased training volume and intensity on hormonal responses (salivary cortisol [C] and urinary dehydroepiandrosterone sulphate [DHEA-S]) and recovery-stress state perceived by 12 female cyclists. Over the 4-day experimental period, there was an average increase in training load of approximately 122% compared with that during the previous 12 days. Scores on subscales of the Recovery Stress Questionnaire for Athletes increased for the somatic component of stress (Fatigue, Emotional Stress and Social Stress; P < 0.05) and decreased the factor indicating recovery (General Well Being; P < 0.05) after the heavy training period. The training programme increased resting concentrations of salivary cortisol (P < 0.05) and decreased the DHEA-S/C ratio (P < 0.05). The increase in training load of cyclists was correlated with this hormonal ratio (r = ?0.48, P < 0.05). Changes in resting cortisol concentration as a result of heavy training stress were positively related to the change in Physical Complaints (r = 0.69, P < 0.01). Negative relationships were also found between changes in the DHEA-S/C ratio and changes in the somatic component of stress. The present results suggest that there is a dose–response relationship between increased training load, resting DHEA-S/C ratio and subjective assessment of stress and recovery, implying that this ratio could be used as an indicator of training status in female athletes.