На главную
В библиотеку
Обсудить в форуме
При любом использовании данного материала ссылка на первоисточник обязательна!
Реклама:
|
PART MOVEMENT CHARACTERISTICS ANALYSIS OF ADOLESCENT WEIGHTLIFTER’S BODY Geng Haijun, Wang Xinna Hebei institute of Physical Education（China） The essay give an analysis on snatch from the perspective of sports biomechanics. And study the technical features the snatch process through sports biomechanics parameters. It is found that the time spent on each process of snatch is not reasonable so that the lifting rhythm is destroyed from some aspect, which is the point that the athlete should pay attention to during training. The athlete should adjust the angle of each lifting process to a suitable position when start using strength. Keywords: weightlifting athletes, snatch, body part, movement characteristics Аннотация. Гэн Хайцэюнь, Ван Синьна. Анализ кинематических особенностей тела штангистов подросткового возраста. Рассматривается выполнение техники рывка штангистами подросткового возраста с точки зрения спортивной биомеханики. Показаны технические особенности выполнения рывка штангистами по анализу основных звеньев тела и кинематическим параметрам. Исследование показало, что не совсем правильным считается выполнение рывка с распределением по времени, в чем нарушается главное правило тяжелой атлетики. Штангисты на этапе приложения силы для выполнения рывка должны найти подходящий угол в звеньях тела для рывка. Ключевые слова: штангист, рывок, части тела, параметры движения. Анотацiя. Ген Хайцеюнь, Ван Синьна. Аналiз кiнематичних особливостей тiла штангiстiв пiдлiткового вiку. Розглядаеться виконання технiки ривка штангiстами пiдлiткового вiку з точки зору спортивноi бiомеханiки. Показанi технiчнi особливостi виконання ривка штангiстами за аналiзом основних ланок тiла i кiнематичним параметрам. Дослiдження показало, що не зовсiм правильним вважаеться виконання ривка з розподiлом за часом, в чому порушуеться головне правило важкоi атлетики. Штангiсти на етапi додавання сили для виконання ривка повиннi знайти вiдповiдний кут в ланках тiла для ривка. Ключовi слова: штангiст, ривок, частки тiла, параметри руху. Introduction Sports talents are the foundation for sustainable development of competitive sports. Today, in China, weightlifting has been a world leader, and whether it can continue to stay focused, the key depends on the training of sports talents ［2］. Then the action of the technical specification young athletes had a thorough discussion of this issue, so as soon as possible to master the technical specification of the action, has some practical significance and theoretical value.Research purposes To eight young women's weightlifting athletes for the study, under the experimental conditions of their snatch action shooting, with three-dimensional constant-speed camera and analytical methods, access to technology players snatch kinematics of the process data and make the reasonable diagnosis to the technical athletes action, provide a reference for coaches and athletes. Results and discussion In the weightlifting movement analysis, every part of the body movement of athlete’s features such as link angle, angular velocity and the grip and also away from the station and other commonly is used as parameters ［3］. The following indicators on the use of the above analysis of athletes in the action phase characteristics.Starting position stage The task of starting position is to do the preparatory work to cite, so that all parts of the body are beginning to mention the bell in the best position for the reasonable force fully prepared. Table 1 Angle of the body part in the preparatory phase
In the preparatory phase of three lower extremities joint angles directly affect the technology in next phase. The three joint angles are too small that athlete’s squat, so that makes the body less flexible, is not conducive to the next stage of development effort, which should pay close attention in peacetime training. As can be seen from Table 1, in the preparatory stage, three joints in the lower limb, hip athletes generally small angle and ankle angle, shoulder angle generally too large, too large shoulder angle is the angle of the lower limbs three small joints of the results, because only increase the shoulder angle in order to make contact with the body to normal posture bar, and keep the bar close to the body, but that makes the shoulder away from the body, an increase of the resistance arm, so that the next stage, more laborious. The correct starting position should be in minimizing the premise of the body center of gravity to keep the joints (especially the lower limbs three joints) at a reasonable angle of force, to prepare for the next phase. In hand from the side, some athletes used in the grip, narrow grip, is not conducive to the economy of force athletes. Because the wide grip can increase upper body forward from the degree of upper body work to make the distance longer, power of larger muscle groups (hip extension and trunk extensor muscle group) can be fully exploited; wide grip relatively lower the height of the bar, saving force; using a wide grip reduces the inner arms and the angle between the bars, thus reducing the arms upward movement of the line. Wide grip the demand grip strength on hand and higher wrist flexibility requirements; this may be one of the reasons that the three players did not use the wide grip. Therefore, they can make appropriate adjustments according to their grip conditions. The stand distance of the eight athletes is within the normal range. Station from the main forces that pull the legs can be fully exploited and concentrated. Pull on the legs too wide, the leg muscle strength will be weakened and when too close, will also affect leg strength into full play when the starting position is easy to tense the leg muscles. In addition, athletes also use the station away from a relationship with the athlete's leg strength, if the athlete's leg strength is relatively large and ankle, hip and knee flexibility off than poor, the standing distance may be appropriate to increase, and vice versa, can be reduced station from. Therefore, the athlete can adjust the station away according to its own conditions, to facilitate the development effort. The stage of mention bell below-knee Rising the bar to a certain speed to the knee, prepare for putting bell for the next phase is the main task of this stage. The power of this phase is mainly comes from extensor muscles, then by the hip muscles from stretching, the bar under the action of these two forces with the body stretched slowly increased. When starting to rise the bell, the extensor muscles forced to actively and decisively, but not too hard［6］. Table 2 The stage of rising bell below-knee to mention various aspects of physical characteristics Unit: (°)
From Table 2, stretch amplitude and the strength contribution of three joints of the lower extremity athletes at this stage is the same that is greater than the hip extension is greater than the extensor stretch ankle. Because at this stage in the full use of the power of extensor muscles while pulling the bar to create the conditions for the hip extension, hip extension and then moderate. This phase of the ankle joint with the body only a slight stretch and stretch, so the ankle joint extension is the smallest of the three legs. But some athletes stretch the ankle angle is greater than the angle of hip extension, ankle extension is too large, is not conducive to major knee and hip joint force. This training should attract attention. Mention at this stage should not bent bell, because the legs and upper body strength than arm is small and premature to mention bell bent legs and upper body strength will suppress the play, is not conducive to full play to the large muscle groups power. The stage, only requires a positive traction arms straight barbell close to the natural pull the calf, then his arms are static nature of the work the muscles supporting the work. From Table 1 and Table 2 of the shoulder, elbow angle can be seen that eight players have five players on the shoulder, elbow have a greater change. This shows that athletes do not master the order of the joint force, can not full play the forces of all aspects. The stage of rising bell above lap The main task of this stage is to exert the most favorable conditions. At this stage, the bar continues to rise from the knee to the thigh on the top 1 / 3 of the moment, the knee angle from big to small, once again back flexion, hip angle from small to big, so that upper body stretch. The length of time at this stage by the grip, body characteristics, circumstances and the balance of power in different parts of the flexibility of the joints is determined［1，5］. Table 3 Lap bell stage to mention the knee and hip flexion and extension as well as barbell vertical velocity changes
From Table 3 that, in time, in eight athletes, there are four reached or exceeded 0.2 seconds, while the average time for elite athletes is 0.14 seconds. If this phase for too long, will not lead to coherent and coordinated action, so that the bar has been greatly weakened inertia force obtained a direct impact on the effect of this stage. In addition to this stage, the three players back to the bend value is too small, because moderate knee extensor muscles of the back bend can get a short "breather" opportunity to mention the knee extensor in the bell in a favorable point of view to be used again, resulting in maximum force when mobilized to participate in extensor muscle mechanical force to create the most favorable conditions. Meanwhile, back knee bent forward and leading to the sinking hip, so hip angle increases, reducing the resistance arm, hip extensor muscles to contract quickly created favorable conditions for the speed and force more economic effort. The other two players back bent knee angle is too large, which is not conducive to further stretch the knee. Because the back knee flexion at this stage is only temporary, for the next phase of knee extension force to prepare again, if at this stage, back bent knee angle is too large, will lead the next phase of knee extension in an unfavorable angle, while excessive knee flexion will lead to barbell back to the speed of decline, damage to force the next phase of the rhythm. Over the knee back of knee flexion may be caused by lack of muscle strength. Suggested that the two players to strengthen the knee strength training, bearing in mind the physical aspects of this phase angle. Eight athletes hip extension range at this stage generally too large, because this stage is only a transitional phase, the development effort for the next stage of preparation, and therefore should not over-extend the hip. If the angle of hip extension is too large at this stage, will result in early release of hip muscle strength, force is not conducive to the next stage. This phase speed of the bar in the vertical direction generally consistent with the laws of this stage, and for the next phase of the force ready. Force phase This stage is in a very short period of time, give full play to the greatest muscle strength, so that the upward movement of the bar to obtain the maximum acceleration in order to rise to the necessary height to squat to support and create favorable conditions. The force is characterized by extensor muscles, hip extensor muscles, shoulder muscles and elbow flexor muscles and leg muscles enough explosive force to make a drastic contraction of kick, hip extension, trunk extension, shrug, put elbow and toes action Pull the bar, all of these actions must be done in a flash, so hard to achieve both muscle coordination and concentration［7，8］. Table 4 Force the body part of the extended phase range
Table 4 shows, this stage is only an athiete, a longer length of time, the other players time to time in force normal range, indicating that athletes at this stage in time force, and maintain the movement coordination. The extent of the knee extension angle of eight athletes are great differences, there are three players stretching more than 60 degrees angle, they may be on a stage in the knee angle is too small, and not in one of the most reasonable force angle. Angle of the knee extension angle solution small angle, the knee may be the last stage of the angle is too large. In both cases do not make the best force in the knee angle, and thus can not fully play extensor muscle strength. Recommended that more attention in future training start time of the joint force angle. The extent of the hip angle stretching eight athletes generally small, the angle is too small is not conducive to stretching the hip muscles stretch full force. Because the force phase kick and stretch the hip is the force at the core of athletes at this stage looking for their own and can give full play to all the joint muscle strength of the force point is necessary, in force position of the body joints at a reasonable of the force point of view, on this basis, try to stretch joints, muscles to play the greatest strength of the joints. Full force when the toes to stretch the ankle, can increase the force strength, improve barbell squat position and the transition from the role. Only eight players in the high forest stretching the ankle angle is too small can be targeted for training in this respect. As can be seen from Table 4, eight players have noticed this stage a positive shrug mention elbow, which is worthy of recognition. Provide a positive shrug elbow can enhance the strength of force, more importantly; control the movement and the bar next to the skin from the braking effect on the body, the body promptly after the fully extended into the squat. In summary, stretching from the joint perspective of eight athletes are not fully in line with the hip extension angle greater than the angle of knee angle ankle extensor stretch than the law, because at this stage to give full play to the strength of large muscle groups, so as to bring heavier weights. Recommended attention in future training in the joints begins to exert an appropriate point of time, but also in the process of force to fully extend the hip and knee. Inertial upswing Studies have found that if the end of the bar to force to do the maximum vertical velocity projectile motion, may continue the upward movement of the bar is less than the distance from the actual inertia of the bar increased distance［4］. This shows that the inertia of athletes in barbell upward phase still put some upward force pulling the bar. Inertia in the barbell upward phase, the body has started buckling down, we can only put up his arms on the bar pulling force. Following this stage the shoulder, elbow angle changes as follows. Table 5 Inertial upswing shoulder, elbow angle change unit: (°)
As can be seen from Table 5, eight players have different degrees of stretching the shoulder joint and shoulder stretch elite athletes within the angle range, indicating the strength of the shoulder joint to play at this stage it is reasonable to help the development effort of completion. Elbow of the buckling strength less than four players, which affected the elbow muscle power play, in peacetime training, should attract attention. Conclusions and recommendations: Player for every aspect of the snatch, the time course of distribution is not very reasonable, to some extent to break the weight of the rhythm. Suggested in the note experience in training athletes lifting movement rhythm. Awareness training should be the major components of reasonable force in order. Athletes in the force phase angle of the body of the main aspects to be further adjusted to find the appropriate force angle. Recommend athletes experience a first angle with the decomposition under the action of muscle in the case, in looking through the whole snatch action appropriate to force their own point of view. Prospects for further research Further action on the women's weightlifting athletes throughout the Kinematics of the process, find out the impact of the action during the action technical factors, to promote the development of women's weightlifting. References: 1. Ai Kangwei. Weightlifting snatch and turning the squat compared with the kinematic characteristics of force. Sports Science. 2005, vol.7, p. 39. 2. Dai Guangyu, Money, Light Kam. Olympic weightlifting. People's Sports Publishing House, 2001, 320 p. 3. Guo Yong Li, Yu Daifeng. Human Movement Science Experiment tutorial. Chinese Literature and History Press, 2003. 280 p. 4. Hu Zhenhao. Woman snatch the biomechanical characteristics of technology. Zhejiang Sports Science. 2003, vol.4, pp. 52-53. 5. Li Shiming. Biomechanics theory and methods. Science Press, 2006, 240 p. 6. Liu Weizhong. Women weightlifters caught jerk force phase characteristics of isokinetic muscle strength. Shanghai Institute of Physical Education, 1997, vol.2, pp. 58-65. 7. Ren Jingping, Liu Xuezhen. China's best female weightlifters snatch technique of biomechanics analysis. Capital Institute of Physical Education. 2006, vol.5, pp. 45. 8. Zhang Jinghong. Lifting force action sports biomechanics analysis. Zhejiang Sports Science, 2000, vol.6, pp 48. Информация об авторах: Гэн Хайцэюнь Ван Синьна Поступила в редакцию 23.03.2012г. Information about the authors: Geng Haijun Wang Xinna Came to edition 23.03.2012. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
При любом использовании данного материала ссылка на первоисточник обязательна!
Реклама:
|