Kinematic analysis of above- and underwater swim start phases of male swimmers aged 16–18 years

Abstract

IntroductionSwim start technique analysis is usually conducted in elite swimmers or only limited to above-water phases. The aim of the study was to analyse kinematic parameters of above- and underwater kick start phases among young male swimmers.Material and methodsThe study group comprised male swimmers (FINA points per 100-m freestyle: 525 ± 84). The subjects performer a 15-m front crawl with kick start. The trials were recorded above and below water with 3 recording devices synchronized with the starting signal. Kinematic analysis by using 2 models (above- and underwater) of body was done. On the basis of time to cover 15 m, 2 groups were distinguished: quickly (FS) and slowly (SS) performing the swim start.ResultsFS and SS demonstrated differences (p < 0.05) regarding hip joint height at starting signal (1.56 ± 0.05 m vs. 1.45 ± 0.05 m), push-off angle (23.89 ± 6.50° vs. 35.12 ± 3.43°), hip joint angle upon completing push-off (163.83 ± 8.37° vs. 149.73 ± 9.93°), and horizontal velocity during flight (3.70 ± 0.35 m/s vs. 3.24 ± 0.22 m/s), submersion (4.88 ± 0.09 m/s vs. 4.36 ± 0.22 m/s), and glide phase (3.40 ± 0.17 m/s vs. 2.99 ± 0.29 m/s).ConclusionsThe obtained results indicate that position on the block significantly influences the movement course in consecutive phases. Young competitors should aim towards elevated hip positioning, allowing to maximize horizontal velocity during the flight, submersion, and glide phases.