897 research outputs found
ANGULAR MOMENTUM IN THE STRAIGHT TKATCHEV ON HIGH BAR
No full textAngular momentum in the straddle Tkatchev was reported as part of a study by Arampatzis and Brüggemann, (2001). The Tkatchev is an interesting skill as it requires the gymnast to reverse the direction of rotation between the bar circling action (the longswing) and the flight phase from release until regrasp
ON THE WAY FROM STRADDLED TO STRETCHED TKATCHEV ON HIGH BAR
No full textReversing the direction of rotation is the main issue for the flight element Tkatchev on high bar. The principles are well described. There is a lack of knowledge to apply this to motor learning. Aim of the study is to analyse an individual gymnast’s performance and support the change from straddled to stretched Tkatchev. An instrumented high bar (force measurement) was used to give the gymnast immediately feedback about the performance. The gymnast was informed about the magnitude of the force maxima during the preparatory giant swing. After 5 training sessions with 42 trails the gymnast transferred more energy (higher forces) to the bar. But this results not in a higher angular momentum during the Tkatchev flight. Possible causes for this result where discussed. The complex demands on energy transfer and precise performance are important
Consistency of performance in the Tkatchev release and re-grasp on high bar
No full textThe Tkatchev on the high bar is a release and re-grasp skill in which the gymnast rotates in a direction during flight opposite to that of the preceding swing. Since the release window is defined as the time during which the gymnast has appropriate linear and angular momentum to ensure the bar can be re-grasped, it was speculated that the release windows for this skill would be smaller than for dismounts which are less constrained. One senior male gymnast competing at national level performed 60 Tkatchev trials. A four-segment planar simulation model of the gymnast and high bar was used to determine the release windows in 10 successful and 10 unsuccessful performances of the Tkatchev recorded using a Vicon motion analysis system. Model parameters were optimised to obtain a close match between simulations and recorded performances in terms of rotation angle (1°), bar displacements (0.01 m) and release velocities (1%). Each matched simulation was used to determine the time window around the actual point of release for which the model had appropriate release parameters to complete the Tkatchev successfully. The release windows for the successful trials were small compared to those of dismounts. The unsuccessful trials were associated with later release and later timing of the actions at the shoulders and hips
Functional phases and angular momentum characteristics of Tkatchev and Kovacs
No full textUnderstanding the technical requirements and underlying biomechanics of complex release and re-grasp skills on high bar allows coaches and scientists to develop safe and effective training programmes. The aim of this study was to examine the differences in the functional phases between the Tkatchev and Kovacs skills and to explain how the angular momentum demands are addressed. Images of 18 gymnasts performing 10 Tkatchevs and 8 Kovacs at the Olympic Games were recorded (50 Hz), digitised and reconstructed (3D Direct Linear Transformation). Orientation of the functional phase action, defined by the rapid flexion to extension of the shoulders and extension to flexion of the hips as the performer passed through the lower vertical, along with shoulder and hip angular kinematics, angular momentum and key release parameters (body angle, mass centre velocity and angular momentum about the mass centre and bar) were compared between skills. Expected differences in the release parameters of angle, angular momentum and velocity were observed and the specific mechanical requirement of each skill were highlighted. Whilst there were no differences in joint kinematics, hip and shoulder functional phase were significantly earlier in the circle for the Tkatchev. These findings highlight the importance of the orientation of the functional phase in the preceding giant swing and provide coaches with further understanding of the critical timing in this key phase
OPTIMISATION TO IMPROVE CONSISTENCY IN THE TKATCHEV ON HIGH BAR
No full textThe purpose of this study was to improve the consistency of performance of the Tkatchev release and re-grasp on high bar. A simulation model (Hiley & Yeadon, 2003) was used to optimise the technique in the giant circle leading up to release in order to maximise the size of the window within which the gymnast could release and successfully re-grasp the bar. The optimal simulation resulted in a release window considerably larger (93 ms) than the gymnast’s actual performances (mean 29 ms).
However, when the technique was required to be robust to small errors in timing the size of the release window was smaller. Performing the final hip and shoulder flexion and extension actions earlier and over a larger angle range than in the actual performances lead to the increase in size of release window
Achieving consistent performance in a complex whole body movement: the Tkatchev on high bar
No full textIf the magnitude of timing and angle variability in whole body coordinated movements were known, this would allow more realistic levels of variability to be included within optimizations of technique. The aim of this study was to determine the technique for improved consistency of performance of the Tkatchev release and regrasp on high bar, while incorporating realistic levels of coordination precision. The effect of gymnast strength and flexibility on consistency of performance was also investigated. Twenty trials (10 successful and 10 unsuccessful) by one national gymnast were recorded using an automatic motion capture system and were analyzed to determine variability in coordination of the giant circle technique prior to release. The standard deviation in the hip and shoulder angles and timings at four key instants in the gymnast’s performances were 2.3° and 12 ms. A gymnast–high bar simulation model was used to optimize the technique in the giant circle to maximize the success percentage for which the gymnast could release and regrasp the bar with coordination variability introduced into each simulated technique. When the optimal solution was perturbed randomly in 1000 simulations to the level seen in the gymnast performances 69% produced a successful performance compared with only 17% for the gymnast. An increase in strength (by 25%) and a reduction in variability (by 25%) lead to improved consistency (91% success rate). Flexibility did not appear to play a role as none of the optimizations approached the bounds set by the gymnast’s performances
Modeling joint kinetics in the Tkatchev release move
No full textThis study developed a three-dimensional computer simulation model of the Tkatchev release move on the men's horizontal bar. The model used the Hanavan human body model and the inverse dynamics approach to predict resultant forces and torques at the joints during performance. The model was used to determine aspects of the performance that contribute to the risk of injury and to determine strength and flexibility requirements for the skill;This study was done in two parts. In Part 1, kinetic parameters were calculated from actual performances of Tkatchevs. Two college-level male gymnasts each performed 9-10 Tkatchevs during a single videotaping session to provide data for developing the model. Videotape of selected performances was digitized and analyses were done to determine joint forces and torques. The high bar was instrumented with strain gages to provide data on reaction forces at the bar;Joint forces of more than 5 times the gymnast's body weight were found, with peak forces occurring at the shoulders and back. Peak torques of up to 670 N-m were found with the highest peaks occurring at the shoulders and upper back;In part 2, the computer simulation model was developed. The joint angles and initial conditions from experimental calculations were used as the initial input for the model. The model was validated using experimental data, then the data were modified and the joint forces and torques were calculated under various conditions;It was found that the force and torque patterns in the simulation closely followed those in the analysis, with minor problems in the giant swing portion. The differences noted could be attributed to the errors involved in the Hanavan body model, in the analysis method, and in the method used to compute the center of gravity trajectory;Several simulations were run to demonstrate the model. The effects of the changes on the angular velocity of the mid-trunk, the forces at the shoulders and the forces at the lower back were summarized to demonstrate the use of the model.</p
The Influence of Body Position on the Straddled Tkatchev’s Flight Phase in Men’s Horizontal Bar
No full textTo examine the effect of level of expertise on the flight phase of the straddled Tkatchev we analysed six male gymnasts (mass = 64.0 +/- 3.0kg, height = 1.67 +/- 0.06m) split into three proficiency levels Elite, Intermediate and Beginners. The preparation phase, flight phase and re-grip phase were sub-divided into ten steps that focussed on three different angularities (bar, shoulder and torso). Angular dimensions between the shoulder and torso and leg were measured using digitised points at the shoulder, trochanter major and lateral malleolus using Sportscode Elite (V10, Sportstec, Australia). A one-way ANOVA was conducted to determine differences between the groups. The results found different angles and body positions influence the flight phase of the Tkatchev. A late flexion in the downward phase with a straight position at the vertical line below the high bar influences the following movement of the Tkatchev positively. An early-piked position with a late straight/hyperextension upward phase increases the energy of the gymnast to reach a greater height above the bar. Both come with a shorten time of preparing and increased time during flight phase. By staring the preparing phase of Tkatchev before reaching the handstand position the gymnast also shorten the time of the giant swing. But then the athlete has to be faster in each execution for each segment, especially in hip flexion during the countermovement. The best time of re-grasping the bar is with a bonded body position and at an angle degree of 412°
RAZVOJ PRVIN NA DROGU GLEDE NA JAPONSKE VIRE
No full textMore recently a total of 800 elements have been recorded in the Gymnastics Code of Points. However few of theses elements made gymnastics history. As such we wonder by whom, when or where these various elements are performed. The purpose of this study was to collate data elements on the Horizontal Bar (HB) in men’s artistic gymnastics and to suggest new elements in the future. The method of study was undertaken by bibliographic analysis. This article refers mainly to journals that were published by the Japan Gymnastic Association, and a list that was made regarding the occurrence of new elements on HB in Men’s artistic gymnastics. From the analysis, the author gatherd data regarding various elememts that were performed. For example, Swing forward and vault backward straddle to hang (Tkatchev) was performed by Tkatchev A. in the 1979 World cup. A Tkatchev stretch was performed by Liukin V. and Nishikawa D. in the 1988 Seoul Olympics. In conclusion, developments of HB elements are greatly influenced by the improvement of apparatus, rules of the era. In the near future, directions of new occurring elements on the HB may add twists to the existing elements.V današnjem pravilniku FIG za ocenjevanje v moški orodni telovadbi je okoli 800 prvin. Za malo teh prvin se natančno ve, kdaj so bile prvič izvedene, kdo jih je prvič izvedel in kje jih je izvedel. Namen članka je bil raziskati pojavnost prvin na drogu z namenom predvideti nove prvine. Uporabljena je bila bibliografska metoda. V članku so predvsem uporabljeni japonski viri, izdani s strani Japonske telovadne zveze in narejen je bil seznam glede na čas pojavitve posamezne nove prvine. Upoštevane so bile različne izvedbe posameznih prvin, npr. Tkačev je izvedel iz predkoleba skok nazaj raznožno v ponovni prijem leta 1979 na svetovnem pokala. Prvič sta stegnjenega Tkačeva izvedla Ljukin in Nišikava na olimpijskih igrah leta 1988 v Seulu. Napredek na drogu so omogočili predvsem razvoj orodja in razvoj prvin. V prihodnosti lahko predvsem pričakujemo prvine z dodanimi obrati
Practical use of airborne simulation in a release-regrasp skill on the high bar
No full textLe but de cette étude est de prédire les améliorations individuelles dans la technique du lâcher-reprise de type Tkatchev. La simulation informatisée permet de confirmer les effets de la correction des paramètres sur la trajectoire aérienne et le mouvement angulaire du corps au-dessus de la barre
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