M.V. Abakumova¹
Dr.Hab., Dr. Biol., Professor K.D. Chermit¹
PhD, Associate Professor A.G. Zabolotniy^1
1Adyghe State University, Maykop

Keywords: javelin throwing technique.

Background. The javelin throwing technique is based on the spatial and temporal structure of linear and angular movement sequences exercised by the kinematic chains of the locomotor system of athletes, which ensures high speed of the projectile at the instant of release. The athlete gains speed and gradually reaches the maximum to perform the springing strides. The transference of speed to the javelin is carried out during the final effort. The high release speed transferred to the projectile through the wrist is generated in the links of the kinematic chain of the athlete’s locomotor system and, to a great extent, determines the result achieved [1, 2, 4]. However, modern literature does not have any information describing the process management mechanism, which ensures that the speed capacities of the links in the kinematic chain are added up to achieve a systemic effect - the maximum projectile release speed. In particular, the dominant links in the kinematic chain and the spatial and temporal structure of the angular speed building process in the kinematic chains of the locomotor system, the basic and specific features of the technique, the rhythmic structure of the activity of the links in the kinematic chain and latent errors remain unstudied. The above positions can be determined through a systemic analysis of the kinematic sequence of actions for angular speed building during the final effort. The realization of this task becomes possible due to the use of a 3-dimensional optical motion capture software system. The systematization of the data obtained will help determine the directions of the methodical support of the training process of javelin throwers of different skill levels.

Objective of the present study was to identify kinematic characteristics of the technique of throwing auxiliary projectile.

Methods and structure of the study. The kinematic characteristics of the auxiliary projectile throwing technique of the  Honored Masters of Sport of Russia Dmitry Tarabin and Maria Abakumova were studied using the 3-dimensional optical motion capture software system [3]. The study was performed at the Ergonomic Biomechanics Study Laboratory of Adyghe State University.

Kinematogram of final effort in auxiliary projectile throw

Results and discussion. The study of the angular movement speed in the kinematic chains of the locomotor system during the auxiliary projectile throw enables to divide the test execution technique into four phases: the unsupported phase, the amortization phase, the phase of taking up the final position, and the final effort phase. Each phase includes the sequence of actions for angular speed building typical for each type of throw.

Thus, in the unsupported action phase, D. Tarabin was found to have a simultaneous hip flexion at the rate of 414 degrees/ sec, knee extension at the rate of 364 degrees/ sec, and ankle flexion at the rate of 561 degrees/ sec (see the table). The maximum angular speeds were recorded at the end of the unsupported actions.

M. Abakumova was found to have another unsupported action pattern: a simultaneous hip flexion at the rate of 134 degrees/ sec, knee flexion at the rate of 240 degrees/ sec, and ankle flexion at the rate of 654 degrees/ sec. The main difference in the unsupported actions of the throwers was that at the moment of placing the right foot on the support, M. Abakumova bended her leg in the knee, and D. Tarabin – straightened it.

Maximum angular speeds in joints in auxiliary projectile throw (HMS of Russia D. Tarabin and M. Abakumova)

After touching the support with the right foot, both athletes moved to the amortization phase, where the direction of the angular movements, which had been established in the unsupported phase, was preserved while the movement speed decreased. D. Tarabin continued simultaneously bending his right leg in the hip, straightening his knee and bending his ankle. The amortization phase lasted 0.05 sec only. He interacted with the support with the forefoot. By the end of the amortization phase, the angular movement speed decreased: in the hip joint - from 414 to 366 degrees/ sec, in the knee joint - from 364 to 269 degrees/ sec, and in the ankle joint - from 551 to 502 degrees/ sec. The amortization phase was completed at the moment of transition from the ankle flexion to the ankle extension.

The amortization phase was different for M. Abakumova. After touching the support, she continued simultaneously bending her right leg in the ankle, knee, and hip. The amortization phase lasted 0.39 sec. She interacted with the support with the whole foot. The angular movement speed in the amortization phase decreased: in the hip joint - from 134 to 95 degrees/ sec, in the knee joint - from 240 to 173 degrees/ sec, and in the ankle joint - from 654 to 39 degrees/ sec. The amortization phase was completed at the moment of transition from the ankle flexion to the ankle extension.

In the phase of taking up the final position, the athletes’ actions were predominantly identical, and the angular speed building was realized by gradually achieving the maximum speed of extension in the ankle and knee joints. The dominant link in the kinematic chain of the locomotor system was the ankle joint, where the highest extension speed was built (see the table). The differences in the throwers’ actions could be seen in the phase duration when throwing with a run-up - 0.24 sec (M. Abakumova) and on a take-off - 0.315 sec (D. Tarabin). The longer duration of this phase enables to longer maintain the high speed of flexion in the hip joint and that of extension in the knee and ankle joints, which creates greater flexibility in the kinematic chain and allows making the final effort using its inertia.

The final effort phase was realized by the gradual achievement of the maximum speed of extension in the hip, shoulder, elbow, and wrist joints. The sequence of actions for building maximum angular speeds was similar for both athletes. At the same time, the phase duration varied. It was 0.4 sec for M. Abakumova and 0.18 sec for D. Tarabin. D. Tarabin spent half as much time on the final effort, which was due to the higher angular movement speed.

Conclusions. The study of the spatial and temporal structure of angular speed building in the kinematic chains of the locomotor system, detected in the Honored Masters of Sport D. Tarabin and M. Abakumova, makes it possible to differentiate between the two final effort techniques: throwing on a take-off and throwing with a run-up.

Throwing on a take-off is based on the unsupported actions performed by the thrower after coming out of the cross-step. Building the high speed of extension in the right knee joint upon placing the right foot on the support enables to swiftly start a repulsion by continuing the knee extension initiated in the unsupported action phase. In addition, the high speed of flexion in the ankle joint allows taking up an advantageous position for performing a powerful reverse movement after placing the foot on the support. In this case, it is only the forefoot that interacts with the support.

The combination of the above actions makes it possible to perform the last step by making a take-off. This technique was throwing on a take-off. Its advantage is the possibility to use more of the inertia of the run-up and minimize the speed losses during the transition from the cross-step to the springing stride. The main technical complexity of such a throwing technique is the need to accurately reproduce the rhythmic structure of the movements under conditions of high speed, i.e., to "play in time".  In this regard, athletes using such a throwing technique may encounter problems associated with action stability. Besides, the process of training of athletes using this throwing technique is more likely to require continuous development of the javelin throwing technique. The visual indicator for determining this throwing technique is that the support is touched with the right forefoot when the last step is taken to make the final effort.

Throwing with a run-up is based on the supported actions of the throwers. The passive actions of the thrower in the unsupported position make it possible to reduce the movement speed, which, in turn, reduces the potential for a run-up, though creates conditions for increasing the accuracy of subsequent actions. The longer duration of the amortization phase by bending the support leg in the hip, knee, and ankle joints enables to create the most advantageous angular positions for the realization of the speed-strength potential of the athlete, while the static interaction with the support with the whole foot through a run-up - to use the reaction force. This technique was called throwing with a run-up. Its advantage is the possibility to unleash the speed-strength potential of the athlete. However, the speed potential of the run-up is to be sacrificed here. The visual indicator for determining this throwing technique is that the support is touched with the whole right foot when the last step is taken to make the final effort.

References

1. Koftun A.I., Boyko Yu.I. Simulator practice in javelin throwers training. Scientific and technical progress and physical education in the Far East. Collected scientific works. Khabarovsk, 1988. pp. 54-58.
2. Hasin L.A., Rafalovich A.B. Javelin throwing structure, built based on analysis of results of high-speed video filming. Moscow, 2015. pp. 139-145.
3. Chermit K.D., Zabolotny A.G. Changes of kinematic characteristics when doing squats in power lifting. Teoriya i praktika fiz. kultury, 2013. No. 8. pp. 73-77. 
4. Campos J., Brizuela G., Ramon V. Three-dimensional kinematic analysis of elite javelin throwers at the 1999 IAAF World Championships in Athletics. Available at: http://www.iaaf-rdc.ru/ru/docs/publication/64.html.

Corresponding author: zabolotniy-tol1@yandex.ru

Abstract

Objective of the present study was to identify kinematic characteristics of the technique of throwing auxiliary projectile.

Methods and structure of the study. We studied the kinematic characteristics of the auxiliary projectile throwing technique of the Honored Masters of Sport of Russia Dmitry Tarabin and Maria Abakumova using the 3-dimensional optical motion capture software system. The study was performed at the Ergonomic Biomechanics Study Laboratory of Adyghe State University.

Results of the study and conclusions. The study revealed the kinematic sequence of actions for building angular speed in the kinematic chain of the locomotor system of athletes. We identified the phase structure of the final effort and the sequence of actions for angular speed building. The data obtained made it possible to differentiate between the two final effort techniques: throwing on a take-off and throwing with a run-up. Throwing on a take-off is based on the unsupported actions of the thrower, while throwing with a run-up is based on the supported actions of the thrower. In addition, it was found that throwing on a take-off requires from the athlete to primarily develop his coordination mechanisms of control of the angular speed in the kinematic chain of the locomotor system, while throwing on a run-up requires organizing a pedagogical action aimed to promote the development of the strength display mechanisms.