رابطه اي برخي شاخص هاي آنتروپومتريكي و بيومكانيكي با اجراي دو تكنيك استارت كرال پشت در بين شناگران دختر و پسر ملي پوش كشور

The Relationship Between Anthropometric Features and Biomechanical Parameters with Close and Open Hand Back Stroke Start Techniques Among Iranian National Swimmers

This study was undertaken to examine the relationship between a few anthropometrical features and biomechanical parameters with open and close hands of backstroke start techniques among male and female Iranian National swimmers. Six males and six females Iranian national swimmers with rang aged between 15-22 participated in this study. Anthropometrical and body composition features which were measured included: height, weight, neck and head circumferences, shoulder wide, length of trunk, arm and forearm, palm, thighs, shanks, feet, body fat percentage, throwing angle, initial velocity, the time and height to reach the peak, as well as the time and distance between the initial position till entering to the water were measured. To determine the body position and biomechanical parameters while performing the two techniques in backstroke start, a video camera and a checked board were used. Findings showed that in male swimmers for the closed-hands technique the length of thigh and body fat percentage were significantly correlated with the starting distance. In female swimmers for the closedhands technique, the length of forearm and circumference of the neck were significantly correlated with the starting distance. In the opened-hands technique, no correlation between male and female swimmers (regarding anthropometrical features) was observed. Though using this technique, a meaningful correlation between height of peak and starting distance was observed between the two groups of swimmers, whereas in the closed-hands technique the correlation between height of peak and starting distance was just observed in males group. All parameters have been meaningfully correlated with the total flight time in both techniques. Regarding the findings of this study, it is necessary to concentrate on the role of the biomechanical features to influence the start in both techniques in backstroke in male and female groups. The findings also proved the superiority of closed-hands technique in backstroke among male members of the group whereas in females group both opened or closed-hands techniques were equal.