Postgraduate K.B. Yasin
Associate Professor, PhD I.V. Petracheva
PhD Yu.N. Kotov
Russian State University of Physical Culture, Sport, Youth and Tourism (SCOLIPC), Moscow

Keywords: kinematics, handball, straight shot technique.

Background

A top priority goal of a handball technique mastering and excelling process in modern handball is to improve the shot execution technique by making the shots more precise and powerful. The more diverse are the shooting techniques in game play the more efficient is the combinatory side of the handball game [1, 5]. Success rates of the straight (walking-position) one-step shots executed by the second-wave offensive players from mid- and long-distances remain low even in the defence-unbounded situations and even when the shots are made by high-ranking handball players [2, 3, 4]. The straight shot technique may seem simple only at the beginner stages of the training process, but the technique perfection and application problems are always rated among the most challenging ones.

Objective of the study was to identify a set of the key shot execution indicators for the straight shot technique efficiency rating purposes.

Methods and structure of the study. The study data was obtained using standard side-view-only video captures of the straight (walking-position) shooting technique. Qualitative and quantitative data of the shot execution sequence were generated by Movement Video Analysis test unit designed for the human movement sequence remote profiling and analyzing based on a remote process video capturing technology. Biomechanical data readings were taken at 50 Hz frequency rate. Star Trace Tracker software toolkit was used to process the video data arrays and generate the movement chain models using coordinates of the markers placed in different points of the shooter’s body to track and profile the linear and angular characteristics of the shot execution technique.

Subject to the study were handball players, students (n = 21) of the Olympic Reserve College #2 (Moscow) aged 21±2.37 years, 1.88±0.09 m high and weighing 81.1±4.74 kg. We used 42 kinematic characteristics to perform a prior cluster analysis to break down the subject into three skill groups. A single-factor dispersion analysis we performed gave us the means to identify a set of the shot technique discriminating indicators to form these groups of differently skilled handball players. “Statistica-10.0” Statistical Software Processing Toolkit was used to perform the mathematical and statistical processing and analysis of the input data.

Study results and discussion. The subject athletes were requested to execute straight shots 9 meters from the goal making three speeding-up steps including the last crossover step. Pulling the throwing hand with the ball back, the handball players made the last crossover step to take the walking position and start the smashing arm throw move. In the preparatory phase of the shooting sequence, the handball players were given time to take the optimal starting stance for the shooting sequence being effective.

Figure 1. Phases of the straight (walking-position) shooting movement sequence

Given on Figure 1 are the key snapshots of the body positions in the phase switchover points of the movement sequence, i.e. the interface postures that served as benchmarks to profile and rate the individual shooting techniques.

In the speeding-up sequence, we made an emphasis on the biomechanical characteristics of the final phase on the whole and the last third step in particular. The back-leg knee bent angles of the Group 1 players (n=7) were found to average 158^о; compared to 151^о of the Group 2 players (n=8); and 161,8^о of the Group 3 players (n=6); albeit the differences of the average knee bent angles were found statistically insignificant (p>0.05).

Table 1. Biomechanical characteristics of speeding-up steps in straight shot sequence executed by handball players’ Groups

Given in Table 1 are the averaged biomechanical data of the leg movements in the speeding-up sequence. The maximal vertical speed rates of the hip joint in Groups 1, 2 and 3 were estimated to make up 1.46 m/s, 1.07 m/s and 0.81 m/s, respectively. The average rates of the maximal angular speeds of the hip joint were found significantly different across these Groups (р≤0.05). These finding gives the reasons to conclude that the higher is the skill level of the player, the faster is the speeding-up sequence and the higher is the contribution of the back leg to the throw. This conclusion is supported by the comparisons of the maximal horizontal/ vertical speeds of the back-leg knee joint in the ball speeding-up sequence.

The final segmental speed in the shooting sequence was found by summarizing the speeds of the bodily segments harmonized in time in the sequential speed-up of the segments and the throwing arm in the upward movement.

Figure 2. Average maximal horizontal speeds of arm segments in straight shot sequence performed by handball players of three Groups

Given on Figure 2 are the average maximal horizontal speeds of the arm segments in the straight shot sequence performed by the handball players of three subject Groups. The Group 1 players showed the higher maximal speeds of the relevant arm segments versus the Group 2 and 3 players. Speeds of the shoulder/ elbow/ wrist/ middle finger distal phalange joints of the Group 1, 2 and 3 players were found to average 4.78; 10.1; 14.4 and 17.5 m/s; 4.28; 9.61; 13.1; and 15.7 m/s; and 4.3; 9.29; 12.7; and 15.3 m/s, respectively. Average ball release speeds of the Group 1, 2 and 3 players were found to make up 24.4; 23; and 22.3 m/s, respectively, with the statistical differences of these rates found significant (р≤0.05).

Figure 3. Average maximal vertical speeds of arm segments in straight shot sequence performed by handball players of three Groups

The maximal vertical speeds of the middle finger distal phalange/ wrist/ elbow joints of the Group 1 and 3 players were found to average 12; 8.93; and 3.69 m/s; and 8.52; 5.88; and 2.71 m/s, respectively (see Figure 3), with the differences found statistically significant (р≤0.05). The higher-ranked handball players were found to develop higher maximal speeds of the arm segments in the final phase of the ball speeding-up movement sequence.

Conclusions

The study found statistically significant differences in the average maximal horizontal and vertical speeds of the arm segments across different skill Groups of the subject handball players, with the higher-ranking players showing notably higher speeds. Therefore, it were the ball release speeds and the maximal arm segment speeds in the final phase of the ball speeding-up sequence that were identified as the key characteristics of the straight shot technique indicative of the player’s skill level.

The higher was the skill level of the player, the higher was found to be the speeding-up step sequence and the back-leg extension speed, with the higher average horizontal and vertical speeds of the back-leg knee joints. Therefore, in the biomechanical-characteristics-based straight shot technique standardization process, due consideration will be given both to the final-phase speeding-up rates of the arm segments and the leg movement rating indicators of the last crossover step in the shooting sequence. 

References

1. Kotov Yu.N. Biomekhanicheskie kriterii ratsional’nosti tekhniki broskov v pryzhke gandbolistok (Biomechanical criteria of rationality of jump shot techniques of handball players ) / Yu.N. Kotov, A.V. Voronov, I V. Petracheva // Teoriya i praktika fiz. kultury. – 2012. – # 4. – P. 72–74.
2. Performance and kinematics of various throwing techniques in team-handball / H. Wagner [et all] // Journal of sports science and medicine. – 2011. – N 10. – P. 73–80.
3. Pori, P. Jump shot performance in team handball-a kinematic model evaluated on the basis of expert modeling / P. Pori, M, Bon, M. Šibila // Journal faculty of sport. – 2005. – N 1. – P. 40–49.
4. Šibila, M. Basic Kinematic Differences between Two Types Of Jump Shot Techniques In Handball / M. Šibila, P. Pori, M. Bon // Journal of faculty of sport. – 2003. – N 1. – P. 19–26.
5. Van den Tillaar, R. Тhree-dimensional analysis of overarm throwing in experienced handball players / R.VD. Tillaar, G.A. Ettema // Journal ap. biomechanics. – 2007. – N 23. – P. 12–19.

Corresponding author: Qaisyaseen1986@gmail.com

Abstract
The work contains a comparative analysis of the characteristics of straight (walking-position) one-step shots for three groups of subjects. The study data was obtained using standard side-view-only video captures of the straight (walking-position) shooting technique. Players with higher skill levels had maximum values of horizontal speeds of arm segments exceeding those of other groups of players. The higher was the skill level of the player, the higher was found to be the speeding-up step sequence and the back-leg extension speed, with the higher average horizontal and vertical speeds of the back-leg knee joints. Therefore, in the biomechanical-characteristics-based straight shot technique standardization process, due consideration will be given both to the final-phase speeding-up rates of the arm segments and the leg movement rating indicators of the last crossover step in the shooting sequence.