Background. Rich theoretical and experimental evidence on the biomechanics of weightlifting exercises has currently been collected (Bauman, Gross, & Quade, 1988; Garhammer, 1991; Gourgoulis, Aggelousis, & Mavromatis, 2000; Isaka, Okada, & Funato, 1996; Шалманов, Скотников, & Панин, 2012). Most of the studies were mainly carried out in laboratory settings, with long-term treatment of the obtained data. In recent years, scientists’ interest has shifted to the study and evaluation of the technical mastery of athletes in the setting of the highest level competition, in the extreme conditions of sport fight. This was facilitated by the development of specialized hardware and program sets (Шалманов & Скотников, 2013; Шалманов, Скотников & Ланка, 2013), opening the possibility for biomechanical control of athletes technical and speed-strength fitness both during the technical training process and competition. One of the ways of evaluating the effectiveness of techniques is based on the idea of using motor capacity by an athlete, which is called efficiency of realization. Methods. To register the trajectory of the bar and calculate kinematic and dynamic parameters of its movement a specialized hardware-program complex (APC) has been developed. In the APC, a photo-video camera “Canon” is included; a marker is fixed on the end of the bar as well as a computer with software. Recording was carried out during major competitions (Cup of Russia, the Russian Championship, and the XХVII World Summer Universiade) in 2012–2014. The total number of athletes surveyed was 331 people (184 men, 147 women). The paper presents the results obtained in the snatch in men. Results. The regularities in the change of kinematic and dynamic bar movement parameter with an increase in weight category and sport result were determined. The main indicator determining sports result in a classic snatch was the absolute maximum power developed by the athlete during acceleration of the bar in the final phase of its lifting: r = .75, p < .001. The indicator of absolute power is the most informative to assess the level of athlete speed- strength fitness, realized due to the efficiency of sports technique and prediction of sports result. Conclusions. The regression equation between the result in the snatch and the maximum absolute power in the final acceleration of the bar give a possibility to evaluate the technique of the effectiveness of each athlete: if it is better or worse than the average one and to what extent. This analysis gave one more possibility – to compare the set up performance with the performance that the athlete, taking into account their level of physical conditioning (maximal power), would achieve if they improve their technique.
Zuša, A., Lanka, J., Vagin, A., & Cicchella, C. (2015). Body segments cooperation during forehand stroke production in young and adult tennis players J. Hum. Sport Exerc., 9(Proc1), pp.S161-S168. The purpose of the study was to investigate biomechanical characteristics of the forehand stroke production in adult and young tennis players, such as body segments cooperation, separation angle (x-factor) and max speed of a racquet. Kinematic data was collected with an optoelectronic motion capture system Qualisys. Participants in the experiment were 6 mid-level adult tennis players (age 19.5 ± 2.3 years, weight 66.8 ± 7.7 kg, height 170.5 ± 7.8 cm, sports experience 13.2 ± 1.7 years) and 4 young tennis players (age 11 ± 0.6 years, weight 43.5 ± 4.8 kg, height 156.3 ± 4.8 cm, sports experience 5 ± 0.5 years). The task of the motion was to carry out 3 forehand strokes for 3 times, the position of the feet and type of stance was not regulated. Results showed that racquet speed during forehand follow through phase, is significantly higher in adult players. Adult athletes have significantly higher x-factor values, which indicates that they more effectively implement muscle-tendon complex pre-stretching principle during backswing and forward swing phase. As well as adults, young tennis players also perform principle of sequential action of body segments during the stroke production, according to their technical skills and level of training.
Zuša A, Lanka J, Čupriks L. Glenohumeral joint muscles strength of the young tennis players. J. Hum. Sport Exerc. Vol. 7, No. Proc1, pp. S8-S16, 2012. This paper consists from two parts. First is small theoretic review about shoulder and upper arm kinematics, biodynamics in forehand and serve strokes. Second is dedicated to study young tennis players' glenohumeral joint muscles strength peak torque, analyzing an asymmetry level of dominant and nondominant side. Five 11 years old girls, weight 42.6 kg (± 5.1), height 157,8 cm (± 5,8) have participated in study. Tests performed with use of Technogym's isokinetic device REV-9000. Mode of the testing -isometric muscle contraction. Verbal and visual feedbacks were utilized to increase the motivation of the subjects. Based on the results of this testing we created individual shoulder joint muscular strength models, that reflects peak torque of right and left shoulder flexion and extension, shoulder abduction and adduction, shoulder internal and external rotation.
Background. Tennis is assumed as asymmetric sport, prolonged training practice could affect muscle strength imbalance. Muscle strength functional ratio imbalance could be a reason for poor posture, physical weakness and increased risk of injury. The purpose of the research was to evaluate young tennis players’ main muscle group strength topography and to investigate the level of different muscles groups’ bi-lateral and contra-lateral imbalance. Methods. The participants of the study were six young right handed competitive tennis players (girls, age 11.4 ± 0.5 years, tennis experience 4.7 ± 0.6 years). Examination of main muscles groups was performed with an isokinetic dynamometer. Results. Young tennis players have pronounced bi-lateral imbalance between shoulder joint extensors and flexors (25%), internal and external rotators (36%), left elbow flexors and extensors (58%), wrist pronator and supinator (the right hand 17%, left 48%), hip flexors and extensors (35%); knee joint flexors and extensors (60%); ankle dorsal flexors and plantar flexors (59%); spine and abdominal muscles (48%). It was detected that young tennis players have pronounced contra-lateral imbalance between right and left internal rotators of the shoulder joint (27%) and external rotators (26%), wrist joint supinators (41%). Conclusions. To avoid the increase in muscle bi-lateral imbalance it is highly recommended to pay more attention to shoulder adductors and shoulder external rotators, elbow flexors and extensors, wrist supinators and extensors, knee extensors, ankle plantar flexors and spine flexors. For contra-lateral imbalance prevention in addition to train non-dominant upper extremity muscles: shoulder internal and external rotators, wrist supinators.
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