The kinematic analysis of 3 repeated 200 metres freestyle swimming performances of swimmers aged 13-15 years: The kinematic analysis of 3 repeated 200 metres freestyle swimming

The aim of this study is to investigate the differences in kinematic parameters of freestyle swimming with respect to young swimmers before and after 3x200 metres (m) performances. Seven male swimmers (mean age: 13.86±0.90; mean height: 164.79±6.89cm; mean mass: 54±5.54kg) participated in this study as volunteers without any injury history. Before the test, the cube calibration was used to calibrate the field for calculation of kinematic parameters. Also, appropriate warming time was given to all participants and then, reflector markers were attached to their selected joints. When the swimmers were ready, they were asked to perform 3x200m freestyle, and their performances were recorded by four underwater cameras (60hz). Stroke length, stroke rate, stroke count, and end time were calculated as performance parameters, while the values of segmental angles were calculated as kinematic parameters using SIMI Motion, version 8.7.2. The differences between the beginning of the first 200m and end of the third 200m performances with respect to kinematic parameters were identified using Wilcoxon Test in SPSS 18.0 (SPSS Inc., Chicago, IL, USA) program. Also, the relationships between performance parameters and kinematic parameters were assessed using Pearson Correlation Cofficient. The results of this study indicate that there is a positive relationship between elbow angle and stroke count (r=.946). Also, there is a negative relationship between stroke length (r=-.934) and stroke rate (r=-.867) at the pull phase, while there are significant relationships between wrist angle, velocity (r=-.838) and end time (r=.824) at the push phase (p<0.05). Keywords: Biomechanics; Freestyle; Swimming; Kinematic analysi