Backstroke to Breaststroke Turning Performance in Age-Group Swimmers: Hydrodynamic Characteristics and Pull-Out Strategy.

Abstract

We compared the hydrodynamic characteristics and pull-out strategies of four backstroke-to-breaststroke turning techniques in young swimmers. Eighteen 11 and 12-year-old swimmers participated in a 4 week intervention program including 16 contextual interference sessions. The hydrodynamic variables were assessed through inverse dynamics, and the pull-out strategy kinematics were assessed with tracking markers followed by 12 land cameras and 11 underwater cameras. Swimmers randomly completed sixteen 30 m maximal backstroke-to breaststroke-open, somersault, bucket and crossover turns (four in each technique) with a 3 min rest. The data showed higher drag force, cross-sectional area and drag coefficient values for the first (compared with the second) gliding position. The crossover turn revealed the highest push-off velocity (2.17 ± 0.05 m·s−1), and the somersault turn demonstrated the lowest foot plant index (0.68 ± 0.03; 68%), which could have affected the first gliding, transition and second gliding depths (0.73 ± 0.13, 0.86 ± 0.17 and 0.76 ± 0.17 m). The data revealed the consistency of the time spent (4.86 ± 0.98 s) and breakout distance (6.04 ± 0.94 m) among the four turning techniques, and no differences were observed between them regarding time and average velocity up to 7.5 m. The hydrodynamic characteristics and pull-out strategy of the backstroke-to-breaststroke turns performed by the age group swimmers were independent of the selected technique.