ObjectiveThe purpose of this study was to determine the differences in technical characteristics between top-elite and sub-elite male weightlifters performing the snatch style in the 69-kg category. The obtained results can provide valuable information for lower level lifters and coaches to achieve better competition performance by altering their training methods accordingly.MethodsSix top-elite and six sub-elite weightlifters participated in this study. The heaviest successful snatch lift from the three attempts of each subject was analyzed. The video data were recorded under competition conditions at China National Weightlifting Championship and China Olympic Trial, which were analyzed by SIMI°Motion7.50 3D analysis system.ResultsThe results showed that the maximum vertical- and relative vertical height (normalized by athletes' height) of the barbell, the maximal vertical linear velocity and acceleration of the barbell were significantly greater in top-elite lifters (p < 0.05). In addition, the flexion angles of the knee joint were significantly greater in top-elite lifters during the first phase and the third phase of the snatch lift. Sub-elite lifters showed less flexion and significantly slower angular velocity in knee joint than top-elite lifters during the second phase of the snatch lift (p < 0.05).ConclusionThe findings of the present study demonstrated the differences in technical characteristics between the two levels. According to these findings, coaches of sub-elite lifters should focus on exercises suitable to the strength characteristics of the first and the third phase of the snatch lift. In addition, the flexor muscles of knee joint among the sub-elite lifters should be strengthened and the ability of generating and utilizing elastic energy during the second phase of the snatch lift should be improved.

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Objective. The purpose of this research was to use a new method the human and bar combination barycenter to exposit the differences between successful and failed characteristics of snatch attempts in competition. Try to establish an effective biomechanical method that can uncover the main factors for the failed snatch. The obtained results will provide valuable information for weightlifters to improve the success rate in snatch by altering their technical issues accordingly. Methods. A 3-D video analysis method was used to compare the characteristics of the heaviest successful and failed attempts of ten elite weightlifters in the men’s 73 kg category. The video was captured under competitive conditions at the 2019 World Weightlifting Championships, the 2019 Asian Weightlifting Championships, and the 2020 China Olympic Trial. The video data were digitized using the SIMI°Motion7.50 3-D system (Germany). Results. Significant difference ( P > 0.05 ) was not found between the successful and failed attempts in the parameters, such as the maximal vertical rising velocity, the maximal vertical height, and the vertical displacement of the barbell. The maximal descending acceleration of the human body, the time duration, the angles of the hip, and knee joints were no significant difference. However, significant differences were found in the variation of the human and bar combination barycenter on the X -axis in the inertial ascent stage and the squat support stage ( t = 2.862 , P < 0.05 ; t = 3.376 , P < 0.05 ). Conclusions. A probable cause of the failed snatch is that the displacement of human and bar combination barycenter on the X -axis is not enough to reach the position for supporting barbell during the inertial ascent stage and the squat support stage. The reason is that the strength of reclining of torso at the end of the force phase is insufficient. Insufficient knee flexion in the knee flexion phase ( M 2 ), which leads to a lower maximum vertical velocity of barbell, may be an indirect factor leading to the failed snatch. The cumulative variation of human and bar combination barycenter on the X -axis can effectively determine the technical characteristics between the success and failure in snatch.

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