Equipment modification can enhance skill learning in young field hockey players

The aim of the study was to investigate whether performance of children can be improved by training with modified equipment that challenges movement execution. For that purpose, young field hockey players practiced with a modified and a regular hockey ball. The modified hockey ball enforces more variable movement execution during practice by rolling less predictably than a regular hockey ball and, thus, challenges the players’ stick–ball control. Two groups of 7- to 9-year old children, with 0 to 4 years of experience, participated in a crossover-design, in which they either received four training sessions with the modified ball followed by four training sessions with the regular ball or vice versa. In a pretest, intermediate test (i.e. following the first four training sessions) and a posttest, the participants dribbled an obstacle parcours with a regular ball. Results show that practice with the modified ball led to greater performance improvement than the intervention with the regular hockey ball. This performance improvement, however, was not predicted by experience and/or initial skill (i.e. pretest score). The findings indicate that by using modified equipment, sport trainers and physical education teachers can, presumably through enhancement of movement variability during practice, stimulate skill acquisition in young children

Measuring the Concurrent Validity of the Athletic Skills Track Using Expert Judgment

Purpose: The aim of this study is to measure the concurrent validity of the Athletic Skills Track (AST) by examining whether its outcome score correlates with the holistic judgments of experts about the quality of movement. Method: Video recordings of children performing the AST were shown to physical education teachers who independently gave a holistic rating of the movement quality of each child. Results: Both intra- and interrater reliability of the teachers’ ratings were moderate to good. The holistic judgments on movement quality were significantly correlated with AST time, showing that higher ratings were associated with less time required to complete the track. Next, hierarchical stepwise regression indicated that in addition to the holistic rating, also age, but not gender, explained part of the variance in AST time. Conclusion: The findings show that the AST has good concurrent validity and provides a fast, indirect indication for quality of movement

Physical map and one-megabase sequencing of the human immunoglobulin lambda locus

The human immunoglobulin lambda (IGL) locus is located on chromosome 22q11.1-q11.2 and contains the genes responsible for the immunoglobulin lambda light chains. This locus was recently mapped (physical map) and its 1-Mb DNA totally sequenced. In this review we focus on the characterization of the v-lambda genes, its chromosomal location, genomics and sequencing of the IGL locus.<br>O locus IGL humano está localizado no cromosomo 22q11.1-q11.2 e contém os genes responsáveis pelas cadeias leves de imunoglobulina tipo lambda. Este locus foi recentemente mapeado (mapa físico) e seu 1 Mb DNA totalmente sequenciado. Nesta revisão focamos os principais resultados de caracterização dos genes v-lambda, sua localização cromossômica, a genômica e seqüenciamento do locus IGL