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.
Highlights
Turning performance is determined by the efficiency of changing direction while swimming between the turn-in and turn-out phases
The optimized performance should derive from a balance between promising hydrodynamic propulsion and minimizing hydrodynamic drag [4,7]
Since no studies are available that focus on analysing backstroke-to-breaststroke turning performance in young swimmers, considering an integrated multifactorial approach, we aimed to compare the hydrodynamic characteristics and pull-out strategies regarding the turn-out performance of four backstroke-to-breaststroke turn techniques in certain age groups of swimmers
Summary
Turning performance is determined by the efficiency of changing direction while swimming between the turn-in and turn-out phases. Swimmers should approach the wall by maintaining speed without compromising the ability to turn and push off the wall as powerfully as possible (allowing the highest wall-out velocity with the least possible drag) [1,2,3]. The swimming-related literature emphasizes that the total turning performance results from increased turn-out efficacy throughout the push-off, glide and swimming resumption phases [4,5,6]. The optimized performance should derive from a balance between promising hydrodynamic propulsion and minimizing hydrodynamic drag [4,7]. Swimmers can improve their turn-out performance by improving their underwater gliding efficiency, both minimizing drag and optimizing underwater timing and distance [6]. Passive drag (Dp) is mainly determined by the swimmer’s
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