A THREE-DIMENSIONAL KINEMATIC ANALYSIS OF HANDBALL THROWS
Keywords: 3-D film analysis, team handball, throwing technique
AbstractINTRODUCTION: The success of a shot in a game of team handball depends very often on the throwing velocity. One of the most important factors affecting ball's velocity is the technique of motion. This technique can be improved by the training process, but for the high performance players that progress is very difficult to achieve. In order to improve the efficiency of that process scientists and coaches should define the most important characteristics of the throwing technique and then develop them during training. The first step leading to this goal is to identify the main parameters of the handball throwing technique. The purpose of this study was to quantify selected kinematic variables of the handball throwing and, in particular, to establish the relationships between athletes' movement patterns and throwing velocity. METHODS: Ten high-performance handball field players took part in the experiment. The average values of basic parameters of physical characteristics of the subjects were: 86.5±9.8 kg body mass, 1.89±0.09 m body height and 22.4±1.8 years of age. The subjects were video taped by two cameras at 60 Hz (CamCoder Panasonic) throwing on the spot from the distance of 7m (penalty shot) to the goal. The cameras were placed perpendicularly at the distances of 14.3 m to the right of, and 31.0 m behind the player. Three-dimensional coordinates of 16 points of each subject with a ball were calculated by combining the images from both cameras. Each throw was digitized and analyzed using the Ariel Performance Analysis System (APAS). Fifty sequences were digitized: 30 frames prior to and 20 frames after the release of the ball. Statistical analysis of the results was carried out with the use of Statistica v. 5.0 software. RESULTS: The following kinematic parameters were defined: duration of the movement, linear and angular displacement of the body parts, and their derivatives - linear and angular velocities. The throwing technique analysis was based on the values of those parameters. The results show that the huge differences of throwing technique parameter values exist even among the high performance handball players. The linear velocity of the ball was 24.45 m/s ± 1.97 m/s (range: 21.11 m/s ¸ 28.50 m/s), horizontal linear displacement of the hand with a ball (XY plane) - 1.74 m ± 0.14m (1.60 m ¸ 2.10 m) and rotational energy of shoulder - 286 J ± 109 J (95 J ¸ 511 J). CONCLUSIONS: The parameters describing the performance were used to estimate the efficiency of the throwing technique. The differences between the values of trunk momentum and the momenta of distal parts of upper limb (arm, forearm, wrist) appeared to be one of the most important factors in the evaluation of throwing technique.
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