Peculiarities of Barbell Motion Trajectory during Snatch Lift of Elite Female Weightlifters

IntroductionThe research of rational sports techniques, pattern of muscles strength change, and methods of improvement of results for certain drills is an integral part of progressive development of any kind of sports, including weightlifting [6, 21]. Trajectory of the horizontal component of barbell motion in sagittal plane in snatch lift and jerk weightlifting is one the most studied technique parameters in weightlifting [21, 24, 27].However, the analyses of references by native and foreign authors showed that the researches of barbell motion trajectory are mostly done in a more complicated coordination motion plane, namely barbell jerk and another motion - pushing from the chest. This is probably caused by the fact that snatch lift technique by the coordination component is simpler, while being similar to the jerk by the biomechanical structure [3, 24, 1]. We consider fundamental researches of elite weightlifters by A. Vorobiyov to be another reason. These researches defined three types of barbell motion trajectory with three sub-types in each that reflect patterns of both jerk and snatch lift. (fig. 1) [28].Another important fact is that scientists have paid attention to the question of which motion trajectory is the most efficient and popular among male and female weightlifters. So, a number of scientists [28, 2] advise to use trajectory A, while W. Baumann et al. [4, 15, 26] suggest type B to be the best one. Others [13, 26] state, based on the results of their researches, that type C is more widely used than others. Moreover, scientists [20] also recommend using type C as the best one.It should be noted that scientists still have no unanimous opinion about which trajectory is the most efficient. Moreover, the results were obtained from the researches mostly done with male weightlifters based on the results of first competition drill (jerk). Also, it should be noted that modern sport is characterized with increasing number of women's events. Certain kinds of sports that have been earlier considered only for men, including weightlifting, grow in popularity nowadays. Competition increases along with sports achievements. However, scarce scientific researches based on female athletes became an obstacle for the realization of educational and training process. Coaches use data obtained mainly from men's achievements.On the other hand, it should be noted that women's body, morphologic structure, functional capabilities, physical development, psychological component etc. differ significantly. At the same time, elite sports results depend on many factors. A slight deviation, a miss, and faults in training process may result in loss of a medal on a tournament.The facts mentioned before prompted us to conduct our own research and define barbell motion trajectories, namely in snatch lift for elite female weightlifters.Materials and MethodsParticipantsData on 140 elite women weightlifters, participants of Europe and World championships, have been used in the research. The data were obtained during Europe Championship in Budapest; Europe Championship in Minsk; World Championship in Istanbul; World Championship in Wroclaw. A total of 304 successful snatch lift attempts have been analyzed. Weight categories included: 48 kg - 13; 53 kg - 12, 58 kg - 24, 63 kg - 23, 69 kg - 31, 75 kg - 17, +75 kg - 20.Organization of the researchThe analysis of bio-kinematic characteristics of motion of elite women weightlifters was done via modern complex based on the use of automated systems of videograms processing on the basis of "Weightlifting analyzer 3.0" video-computer complex (Germany). Defining the type of barbell motion trajectory during snatch lifting became an important stage in our research. The basic motion of the grip end was done in sagittal plane. The analysis was performed by the three types of barbell motion trajectory (fig. 1). Type A is a type of trajectory, according to which the barbell approaches weightlifter's body in the first stage of the pull (point c) immediately after the first pull. …