مقایسه متغیرهای منتخب کینماتیکی استارت تک‌پای جلو وزن و عقب وزن شناگران پسر نخبه

Objective: Over recent years, due to scientific advances in various aspects of sport, rapid development and improvement has taken place in sport performance standards as well as athletes' performance. In the swimming tournaments, on-time and correct start, plays an important role in the success of swimmers, especially speed swimmers. The aim of this study was comparising selected kinematic variables in front and rear- weighted track start of elite male swimmers. Methods: Fourteen elite male swimmers with an average age of 17.86&plusmn;1.92 years selected from among an available sample of those who had better starts and had the right foot (dominant legs) place in this study. The following kinematic parameters were analysed: take off angle, take off velocity, entry angle, entry velocity and flight distance. Using a top speed of 100 fps video camera to detect body position and biomechanical parameters during the performance of two start techniques. The statistical procedures to analyze the data included Kolmogorov-Smirnov test to chek for normal distribution of the data and T-test for comparing the kinematic quantities of two types of start with at 0.05 alpha levels. Results: The findings indicated that there was a significant difference in the flight distance between two start techniques (P<0.05) and that the distance at Frontand- weighted track start was more than the distance at rear- weighted track start. As to the other components, including angles and speeds from the platform, angle and speed of entering the water, no significant differences were found between two types of front- and rear- weighted track starts (p <0.05). Conclusion: Because of the difference in flight distance and time off the platform due to the positioning of the center of gravity in the two types of starts, coaches and swimmers can use either of the two starts depending on the type of competition (speed and endurance of swimming).