Validation of an instrument for qualitative evaluation of the Crawl stroke

Abstract

The lack of instruments to evaluate the crawl stroke, based on recent assumptions regarding technical efficiency and range of styles for a single stroke, has posed difficulties to both swimming coaches and motor behavior researchers. The objective of this study was to propose and validate an instrument for evaluating Crawl stroke qualitatively. A proficiency list with the most frequent technical errors was elaborated, ranked according to the sub-components of the stroke in twelve categories. In order to perform the validation of the instrument, seven childrens (four boys and three girls), with at least one year of swimming experience and age of 10.5 (±2) years, had their displacements videotaped (above and underwater). Three competitive swimming experts, with academic graduation, evaluated the content of the checklist. Then, intra- and inter-examiners correlations were determined. The results confirmed that the content of the list showed clarity and satisfactory technical pertinence and good applicability. As for consistency and reproducibility, it is possible to infer that the checklist is adequate since the intra-examiner correlation was between 0.83 and 1.0 and 91% of the correlations were above 0.9. The inter-examiner correlation, on the other hand, was between 0.50 and 1.0 with 90% of the correlation above 0.9. Thus, the checklist used to evaluate the proficiency level for the proposed stroke seems to be valid and to take into account individual differences, magnitude and meaning of the technical erros.