Segment coupling and coordination variability analyses of the roundhouse kick in taekwondo relative to the initial stance position

The initial stance position (ISP) has been observed as a factor affecting the execution technique during taekwondo kicks. In the present study, authors aimed to analyse a roundhouse kick to the chest by measuring movement coordination and the variability of coordination and comparing this across the different ISP (0°, 45° and 90°). Eight experienced taekwondo athletes performed consecutive kicking trials in random order from every of the three relative positions. The execution was divided into three phases (stance, first swing and second swing phase). A motion capture system was used to measure athletes’ angular displacement of pelvis and thigh. A modified vector coding technique was used to quantify the coordination of the segments which contributed to the overall movement. The variability of this coordination (CV) for each ISP was also calculated. Comparative analysis showed that during the stance phase in the transverse plane, athletes coordinated movement of the trunk and thigh with a higher frequency of in-phase and lower frequency of exclusive thigh rotation in the 0° stance than the 90° stance position (P < 0.05). CV was also influenced by the different ISP. During the first swing and the majority of the second swing phase, predominant in-phase coordination of the pelvis and thigh was observed. Including exercises that require in-phase movement could not only help athletes to acquire coordination stability but also efficiency. The existence of a constraint such as ISP implies an increase of the variability when the athletes have to kick from ISP they are not used to adopt (i.e., 0° and 90° ISP) as an evidence of adaptability in the athletes’ execution technique.     

Factors associated with caregiver stability in permanent placements: a classification tree approach

Objective

Identify individual and environmental variables associated with caregiver stability and instability for children in diverse permanent placement types (i.e., reunification, adoption, and long-term foster care/guardianship with relatives or non-relatives), following 5 or more months in out-of-home care prior to age 4 due to substantiated maltreatment.

Methods

Participants were 285 children from the Southwestern site of Longitudinal Studies of Child Abuse and Neglect (LONGSCAN). Caregiver instability was defined as a change in primary caregiver between ages 6 and 8 years. Classification and regression tree (CART) analysis was used to identify the strongest predictors of instability from multiple variables assessed at age 6 with caregiver and child reports within the domains of neighborhood/community characteristics, caregiving environment, caregiver characteristics, and child characteristics.

Results

One out of 7, or 14% of the 285 children experienced caregiver instability in their permanent placement between ages 6 and 8. The strongest predictor of stability was whether the child had been placed in adoptive care. However, for children who were not adopted, a number of contextual factors (e.g., father involvement, expressiveness within the family) and child characteristics (e.g., intellectual functioning, externalizing problem behaviors) predicted stability and instability of permanent placements.

Conclusions

Current findings suggest that a number of factors should be considered, in addition to placement type, if we are to understand what predicts caregiver stability and find stable permanent placements for children who have entered foster care. These factors include involvement of a father figure, family functioning, and child functioning.

Practice implications

Adoption was supported as a desired permanent placement in terms of stability, but results suggest that other placement types can also lead to stability. In fact, with attention to providing biological parents, relative, and non-relative caregivers with support and resources (e.g., emotional, financial, and optimizing father involvement or providing a stable adult figure) the likelihood that a child will have a stable caregiver may be increased.     

Component structure,reliability, and stability of Lawrence’s Self‐Esteem Questionnaire (LAWSEQ)

Lawrence’s Self‐Esteem Questionnaire (LAWSEQ) was administered to 120 Year 1 pupils in six schools in Belfast, Northern Ireland. A principal components analysis indicated that the scale items were unidimensional and that the reliability of the scores, as estimated by Cronbach’s alpha, was satisfactory (α = .73). There were no differences between boys and girls on either total scores or the individual items comprising the LAWSEQ. A follow‐up study, involving 71 of the children in Year 3, confirmed these findings but the stability of the scores between the two occasions (as indicated by Pearson’s r) was extremely low.     

Does cardiopulmonary resuscitation cause rib fractures in children? A systematic review

BACKGROUND: There is a diagnostic dilemma when a child presents with rib fractures after cardiopulmonary resuscitation (CPR) where child abuse is suspected as the cause of collapse. We have performed a systematic review to establish the evidence base for the following questions: (i) Does cardiopulmonary resuscitation cause rib fractures in children? (ii) If so, what are the frequency and characteristics of these fractures that may help to distinguish them from rib fractures caused by physical abuse? METHODS: We performed a literature search of original articles, references, textbooks, and conference abstracts, published in any language from 1950 to 1 October 2005. Articles were identified from ASSIA, Caredata, Medline, Ovid Medline in Process, ChildData, CINAHL, Embase, ISI Proceedings, SIGLE, Science Citation Index, Social Science Citation Index, and TRIP databases. We included all studies that addressed rib fractures and CPR in children less than 18 years, and excluded review articles, expert opinion, consensus guidelines, and studies that were significantly methodologically flawed on critical appraisal. Each study underwent two independent reviews (with a third review if there was disagreement). Each reviewer used standardized criteria for study definition, data extraction, and critical appraisal, to determine the quality of the study and to establish if it met the inclusion criteria of this systematic review. FINDINGS: Of the 427 studies reviewed, 6 were included: 1 case control, 4 cross-sectional, and 1 case series. These represent data on 923 children who underwent CPR. Three children sustained rib fractures as a result of resuscitation; all three of these had fractures that were anterior (two mid-clavicular and one costo-chondral). We did not find any child in the literature who had a posterior rib fracture due to CPR. Resuscitation was performed variably by both medical and non-medical personnel. CONCLUSION: Rib fractures after cardiopulmonary resuscitation are rare. When they do occur, they are anterior and may be multiple. As the studies performed to date did not use the most sensitive techniques for detecting rib fractures, further prospective studies of children would be valuable to provide additional clarification on this question.