The kinematic analysis of the different start methods in swimming

The purpose of this investigation is to compare the affect of grab start (GC), front-weighted track start (OTC) and rear-weighted track start (ATC) on performance as kinematical in swimming. So firstly, necessary permission was taken from the Ethical Committe of Akdeniz University. Totally 12 elite competitive swimmers (mean ± S.D., age: 15,25 ± 0,97 years, training years: 6,83 ± 1,03 years, body height: 170,25 ± 5,79 cm, body mass: 61,58 ± 7,28 kg) who prefer OTC method and particpate in Turkey swimming championships on behalf of the same swimming club included in the study. Reaction, impulse, block and flight time, time from start to water touch, the horizontal and vertical velocity of the center of mass (CM) at takeoff, flight distance, horizontal velocity of the CM at the beginning of the water entry, angle of takeoff / entry, and the first 10 meters performances of participants were examined. In this study, 3D videography method was used. Swimmers performed three times GC, OTC and ATC. Two high speed and working synchronized recorded the starts of participants. The shots were directly transferred from camcorders to the computer. Kinematical analysis of acquaired data were made by using SIMI Motion 6.2 program. Data has been assesed by SPSS 18.0. Repeated Measures ANOVA tests and "Bonferroni Adjustment" were run for parametric data. For non-parametric data "Friedman Test" and Wilcoxon Test" were run. Results were shown as "mean ± S.D.". Results have been assessed according to the significant level < 0,05. Swimmers using the OTC (0.85 ± 0.04 s) left the block significantly earlier than ATC (1,16 ± 0,09 s) and GC (0,91 ± 0,05 s; p < 0,01). (0,85 ± 0,04 s), significantly later using the ATC (1,16 ± 0,09 s), (GC: 0,91 ± 0,05 s; p < 0,01). However ATC using athletes are advantaged as they left the blocks with significantly higher horizontalvelocity than both GC (3,87 ± 0,11 m/s) and OTC (3,89 ± 0,07 m/s; p < 0,01). In the ATC (4,54 ± 0,13 s), 10 m time compared to other methods (GC: 4,72 ± 0,12 s; p < 0,01, OTC: 4,69 ± 0,10 s; p < 0,05) was found significantly shorter. According to the findings, ATC?s disadvange by block and flight time turned into an advantage during horizontal velocity of the CM at takeoff which lengthens flight distance indirectly through the takeoff movement starts by rear foot. Besides this, ATC gets more advantage by a fast horizontal velocity with an optimum takeoff angle, then with an optimum entry angle if not lost during gliding phase because of water resistant. The most significant indicator which expresses this advantage of ATC is that it has clearly shorter 10 m time than other two methods. Keywords: 3D kinematic analysis, biomechanics, motion analysis, grab and track start, front-weighted and rear-weighted track start.