Variables críticas del viraje de espalda en natación, Evolución a lo largo de la prueba e influencia del nivel del nadador

Resumen

In swimming, competition turn analysis has usually been done considering pre-established distances before and after the touch of the wall; in this situation, no other studies calculated in competition some backstroke turn kinematic characteristics besides turn time. Filming two groups of swimmers (national and regional) participants in the Spanish Swimming Championships and using 2D-DLT algorithm-based analysis for the study of 200 meter backstroke turns, we calculated specific backstroke turn variables in competition. Besides determining some kinematic turn characteristics, we checked the influence of swimmers level on «turn time», «distance in», «distance out» and «average speed out», analyzing also their evolution through the 200 meter event. Our results show that national level swimmers obtain statistical faster «turn time» and «average speed out», longer «distance in» and equal «distance out» than regional level swimmers. The evolution of the variables through the event shows a clear tendency of an increasing «average speed out» and a decreasing «distance out» for both swimmers groups, while national level swimmers keep «turn time» and other variables more stable through the event. Backstroke turn variables delimitated by technique elements seem to provide more accurate information in comparison with a classic turn variable like turn time.