Can young students understand the mathematical concept of equality? A whole-year arithmetic teaching experiment in second grade

European Journal of Psychology of Education - Ensuring students correctly understand the notion of equality is a fundamental problem in teaching mathematics. Is it possible to teach arithmetic in...     

Publication trends for single-case methodology in school psychology: A systematic review

Single-case design (SCD) is a research methodology that may be utilized to establish the presence of a functional relation between an independent and dependent variable. Recent research has found the design to frequently be used within school psychology in the evaluation of intervention procedures. However, the overall prevalence of the design within the broader school psychology literature is unknown. As such, the purpose of the current review was to identify trends in the use of SCD within school psychology publications. Furthermore, the review sought to identify institutions and journals that most frequently published SCD. Finally, the review sought to evaluate trends in experimental rigor of published SCD. Twelve journals were examined, with all publications since their inception reviewed and classified by publication type. Results of the review indicated that SCD was the least frequently published article type. However, data indicate an increase in the prevalence and rigor of the design in recent years. Whereas some journals and institutions were found to have steady rates of SCD publications, others were found to have recent increases in the publication of the design. Implications of findings as they pertain to practitioner practice and adoption of evidence-based practice are described.     

Jason Lezak again and again - linear mixed modelling analysis of change–over times in relay swimming races

The aim of this study was to examine the importance of the change-over time in swimming relay races. Top-class international 4 x 100 m freestyle races were analysed across a 10-year period including three Olympic Games and five European and World Championships. A total of 220 swimmers (116 female, 104 male) were included in this study with an average participation of 1.7 ± 1.2 races. To consider such repeated measurements and other factors (e.g., ranking in the relay race, position in the relay team) linear mixed models for longitudinal data were used for the statistical evaluation. Our results showed significantly longer change-over times for male medallists (0.23 ± 0.08 s) than non-medallists (0.20 ± 0.09 s) which reflects a very likely effect (94.2%). Furthermore, there were significant differences in change-over times between female and male swimmers depending on the current race positions. In total, the influence of change-over time on the final performance in 4 x 100-m freestyle relay appears to be overrated in previous studies.     

Learning relay start strategies in swimming: What feedback is best?

In the past, studies and book recommendations on relay starts in swimming have been predominantly focused on the change-over time (COT) as a performance criterion. Aside from the circular backswing start with parallel foot placement, few studies have analysed differences in the take-off movement including step approaches as well. Although trends could be identified, the results remained still somewhat inconclusive. In contrast, no study has examined as has examined whether a reduction of COT in between wall contact of the income swimmer and the take-off of the outgoing swimmer is an optimal relay start strategy, as advocated by various swimming experts. Therefore, the purpose of this study was to compare two different relay start strategies: offensive strategy minimizing COT and conservative strategy to maximize horizontal peak force (HPF). In this regard, a learning intervention with 24 elite-level swimmers (12 females, 12 male) was conducted to compare both strategies regarding relay start time, HPF and COT. Subjects were randomly assigned to two feedback groups: COT versus HPF at take-off. The results of this study showed a clear advantage for HPF feedback for relay start performance measured by wall contact of the incoming swimmer and head passage at 7.5?m of the outgoing swimmer. In addition, similar reductions in COTs were found in both training groups. In conclusion, swimmers should focus on force production rather than minimizing COT. For the latter, deteriorating consequences for force production must be considered.