The study aim was determining gender-related differences of underwater undulatory swimming (UUS) kinematic indicators and their impact on UUS velocity. Methods: The study included 18 girls (F: age 16.71 ± 0.64 years, FINA points 551 ± 68) and 23 boys (M: age 16.79 ± 0.57 years, FINA points 533 ± 66) training swimming. After marking characteristic anatomical points, subjects performed approximately 7 meters of UUS. A filming device placed behind the underwater window registered the trial. Recordings were analysed using the SkillSpector programme.

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Purpose. The aim of the study was to distinguish the kinematic indicators influencing the average horizontal velocity of swimming (v cOM ) with underwater dolphin kicks (UDK). Methods. The study involved 15 boys and 20 girls (mean age, 11.5 ± 1.00 years; height, 1.57 ± 0.09 m; training experience, 2.5 ± 1.00 years) practicing swimming 7 times a week. We determined the body height (H), the length of the body with the arms lifted (L b ), and the best result in the 50-m freestyle (pbt); characteristic anthropological points were marked on the body. The subjects performed UDK after a water-start for a distance of ca. 8 m (without a push-off from the wall). Movements were recorded with an underwater camera. The recordings were kinematically analysed with the SkillSpector program. On this basis, we calculated v cOM , frequency of movement (f), amplitude of movement (A), horizontal displacement in one cycle (D pk ), maximum flexion in the knee joints (KF max ), the product of f and A (I Af ), the Strouhal number (St), and relative amplitude of toe movement (A rEL ).Results. The movements of the subjects were characterized as follows: v cOM = 1.08 ± 0.13 m/s, f = 2.00 ± 0.

Purpose. swim 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. Methods. the study group comprised male swimmers (FINA points per 100-m freestyle: 525 ± 84). the subjects performed 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.Results. Fs 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). Conclusions. the 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.

Race analysis performed by faster and slower swimmers enables the definition of effective strategies for carrying out the competition. Until now, measurements of this type were mainly conducted among top-level athletes. The aim of the study was to determine the differences in swimming technique in sprint races between faster (FS) and slower (SS) regional-level swimmers. The performance of 33 swimmers (mean FINA points = 449) competing in 50 m and 100 m freestyle races was analysed. To determine the velocity (v), stroke rate (SR), stroke length (SL), and stroke index (SI), races were recorded with the use of cameras. Using the Student’s t-test and Mann–Whitney U test, the results were compared for two groups: FS (mean FINA points = 557) and SS (mean FINA points = 379). In the 100 m competition, differences between groups were noticed in v (1.70 and 1.51 m/s), SL (2.06 and 1.85 m), and SI (3.52 and 2.80 m2/s), while in the 50 m competition, they were noticed in v (1.95 and 1.73 m/s), SR (59.46 and 55.01 cycle/min), and SI (3.44 and 3.04 m2/s, respectively for the FS and SS groups). Adapting the technique to a shorter distance should be performed by increasing the frequency of movements. At the same time, the decrease in SL should be controlled. The indicator enabling the assessment of technical effectiveness, regardless of the distance, is the SI. The 50 and 100 m freestyle races require specific technical skills to be mastered. Therefore, the development of technique in swimmers should include its various variants.

The purpose of this study was to examine the relationship between a unique complex of predictors and 100 m front crawl race kinematics and swimming speed. In 28 male competitive swimmers (age: 19.6 ± 2.59 years), the following groups of predictors were assessed: (a) the morphologic, (b) the functional upper limb range of motion, and (c) the anaerobic indices of arm-cranking and a series of countermovement jumps. The Pearson product-moment correlation coefficient was calculated to distinguish the predictors and the swimming results. The main finding was that the indices of the power (arm-cranking) and the work (countermovement jump) generated in the anaerobic tests showed a significant and higher correlation with stroke length and stroke index than total body length, upper limb range of motion, or hand and forearm surface area. These results were obtained in accordance with the high swimming economy index relation to clear surface swimming speed. This study reveals that the strength generated by the limbs may represent a predictor of swimming kinematics in a 100 m front crawl performance.

Aim: Determining the relationship between time of swim start and the power of the lower limbs in boys and girls. Basic procedures: 32 swimmers, aged 15-16 years performed the CMJ (counter-movement jump) and the SJ (squat jump). The following were measured: jump height (H), maximal speed (vMAX) and maximal power as well as the average in absolute (respectively: P and PA) and relative terms (PREL and PAREL). Registration Recording of the start jumps to any style freestyle with the measurement of the time to cover the first 10 m of the distance was were conducted (t10). The following were determined: flight length and time (Lf, tf), height of hip joints at the time of start signal (Hh), angle in of the hip joints at the time of loss of contact with the block (AT) as well as at the time of immerging fingers in the water (AE), and the water attack angle (AA). The significance of differences between averages noted in the groups of boys and girls were evaluated and the correlations between variables were described. Main findings: The boys achieved lower t10 values and higher Lf, Hh and AT levels. In this group of subjects, only Hh negatively correlated with t10 (r=-0.57). Significant differences in the level of all variables noted for the boys and girls during the CMJ and SJ were observed. At the same time, none of the indicators characterizing CMJ were correlated with t10. In the group of boys, significant correlations were noted between t10 and H, vMAX, P, PREL, PA in SJ (-0.51≤r≤-0.72). Conclusions: There are differences between the boys and girls in performance of the start jump. One of their causes may be the disproportion in the strength of lower limb muscles. In boys, unlike girls, the SJ jump is valuable in testing the power of the lower limbs significantly correlated with the effectiveness of the start jump. The CMJ jump seems to be of low usefulness in predicting the effectiveness of a swim start.

Introduction: The introduction of a starting block with an adjustable and slanted footrest has caused the development of a new starting technique - the Kick Start. Therefore, research on swim start seems necessary, particularly concerning the Kick Start underwater phase. Aim: The study aim was to characterise the underwater phase of the Kick Start among young, male, competitive swimmers. Basic procedures. The study included 32 male, youth, competitive swimmers (mean age=16.61 years, height=1.80 m, body mass=72.47 kg, FINA Points=617). Participants executed three freestyle Kick Starts recorded using an underwater high-speed camera. Videos were kinematically analysed using the Skill Spector programme. Then, k-means clustering was applied. Results. Participants were classified into three clusters. Cluster FT (“flat trajectory”) comprised swimmers with a ”flat” course of underwater movement - low value of the angle of water attack (KA=0.92o), maximum depth of the head (hmax=0.85 m), distance (dmax=0.71 m), and time to maximum depth of the head (tmax=0.51 s). Group MT (“moderate trajectory”) had moderate values of the above-mentioned parameters (KA=10.27o, hmax=0.93 m, dmax=1.03 m, tmax=0.60 s), while Cluster DT (“deep trajectory”) achieved the highest values (KA=15.74o, hmax=1.05 m, dmax=1.38 m, tmax=0.73 s). The time to reach 15 m in Cluster FT was about 0.3 s slower than in Group MT and DT, although this dissimilarity was not significant. Conclusions. The course of underwater movement is mostly affected by the angle at which swimmers submerge. There is no “ideal” way to perform the underwater phase, however, it should not be executed too close to the water surface.