Kinematic variables of table vault on artistic gymnastics

Vault is one of the artistic gymnastics events, either for males and females competitions. Since 2001, vault regulations include an approach running of 25 m, a springboard and a rectangular table with a surface measuring 1.20 m x 0.95 m.  e table height is di erent among males (1.35 m), females (1.25 m) and juniors categories (1.15 m).  e competition regulations require from a gymnast to perform two vaults from  ve groups, characterized by di erent approaching positions on the table (FIGURE 1). For males, the number of vaults coded in each group are: 34 in group I (forward handspring), 24 in group II (handspring with 1⁄4 turn in the  rst  ight phase, Tsukahara), 19 in group III (round o entry, Yurchenko), 16 in group IV (round o entry with in group the  rst  ight phase, Nemov) and 14 on group V (round o entry with turn in the  rst  ight phase of the jump, Scherbo), in a total of 107 vaults coded. For females, the number of vaults coded in each group are: 24 in group I (handspring), 14 in group II (handspring and salto), 12 in group III (1⁄4 or 1⁄2 turn in the  rst  ight phase, Tsukahara), 19 in group IV (round o entry and salto, Yurchenko) and 11 on group V (round o entry with 1⁄2 turn in the  rst  ight phase), in total of 80 vaults coded. Due to those coded vaults, research would be needed about general concepts of vaulting biomechanics, to develop principles for qualitative application of biomechanics to improve movement performance and to reduce the risk of injury. Abstract


Introduction
Kinematic variables of table vault on artistic gymnastics CDD.20 Vault is one of the artistic gymnastics events, either for males and females competitions.Since 2001, vault regulations include an approach running of 25 m, a springboard and a rectangular table with a surface measuring 1.20 m x 0.95 m. e table height is di erent among males (1.35 m) 1 , females (1.25 m) 2 and juniors categories (1.15 m) 3 .e competition regulations require from a gymnast to perform two vaults from ve groups, characterized by di erent approaching positions on the table (FIGURE 1) 1 .
For males, the number of vaults coded in each group are: 34 in group I (forward handspring), 24 in group II (handspring with ¼ turn in the rst ight phase, Tsukahara), 19 in group III (round o entry, Yurchenko), 16 in group IV (round o entry with in group the rst ight phase, Nemov) and 14 on group V (round o entry with turn in the rst ight phase of the jump, Scherbo), in a total of 107 vaults coded 1 .For females, the number of vaults coded in each group are: 24 in group I (handspring), 14 in group II (handspring and salto), 12 in group III (¼ or ½ turn in the rst ight phase, Tsukahara), 19 in group IV (round o entry and salto, Yurchenko) and 11 on group V (round o entry with ½ turn in the rst ight phase), in total of 80 vaults coded 2 .
Due to those coded vaults, research would be needed about general concepts of vaulting biomechanics, to develop principles for qualitative application of biomechanics to improve movement performance and to reduce the risk of injury 4 .

Abstract
The table vault is an event of male and female Artistics Gymnastics.Although it can be performed in a variety of rotations and body positions in different phases, it can be separated in three groups: handspring, Yurchenko and Tsukahara.It is believed that kinematic variables of vault may vary according to group of vault or gymnast body position, but few studies compares the real differences among the three groups of vaults, comparing and describing the variables in different phases.Vault kinematic variables could be diversifying according to the approach or position of the vaulting, but little has been studied about the biomechanical differences, comparing and describing behaviours at different stages.The aim of this study was to organize critical, objective and to systematize the most relevant kinematic variables to performance on vaulting.A Meta analysis over the basis Pubmed, Sport Discus and Web of Science were performed about this issue.From the selected references, we described and analyzed the kinematics of the table vault.Vault can be characterized in seven phases of analysis.Most of the studies are descriptive, and some do not descript all phases.Differences among vault variables according to group vaults, technical level and gender were analysed only in recent studies.There still gaps of knowledge about kinematic variables of table vault, in order to provide comprehensive information about all possibilities of vaults in this gymnastic event.It is concluded that kinematic variables of table vault depends upon vault group and may be considered to the improvement of technical performance.More researches are needed to approach the coaching interface with biomechanics applicable knowledge.KEY WORDS: Gymnastic; Vaulting; Kinematics.erefore, one main need for research in gymnastics and biomechanics is to present objective and systematic knowledge about the apparatus and provide information to the coaches in eld 5 .
An understanding of the biomechanics variables related to the vault groups, body position (tucked, piked or stretched), the number of rotations around the transversal and longitudinal body axis, gymnasts sectors and categories would provide information about the research gaps.Also, to present coaches with a comprehensive understand about what is already known 6 .If there are di erences between vault groups would explain individual gymnast performance needing to attend e scienti c questioning about the reference parameters that base coaches actions 6 .Due to the complexity and variability of motor actions in gymnastics, it is pertinent to analyze each event separately.Close monitoring of the evolution of skill on table vault apparatus is paramount for gymnastics coaching 13 .
Coaches' access to applied biomechanics knowledge is also limited because the youth of biomechanics means there are fewer narrative or meta-analysis review papers on sport biomechanics issues 4 .In Artistic sports where it is important the presentation, the technical level and the increase of complexity, it is necessary to analyse kinematic aspects of performance, and competition requirements.It is necessary to organize biomechanical-based classi cation for the exercises in artistic gymnastics [7][8][9][10][11] .In order to approach such proposal, is there biomechanics di erences regarding the vault types and table height?Is there the group vault more preferable or e cient?e understanding of the performance variables in a sportive movement is fundamental to improve gymnasts technical achievements 4 .Such variables, when interpreted and manipulated, are important to understand the adaptations and limitations of movement patterns, by complete characterization of sportive movement, and to elaborate a plan of action to improve performance 12 .

Method
This meta-analysis research was conducted based in papers within the data basis: Pubmed, Sport Discus and Web of Science. is search was performed in those databases from 1980 up to 2015.Moreover, book of abstracts with reviewing process from International Society of Biomechanics, International Society of Biomechanics in Sports and Brazilian Society of Biomechanics were included.
e keywords used in English were: "gymnastics" and "vault" and "kinematic"; and in Portuguese: "ginástica" and "salto" and "cinemática".From the resulting references, papers that have considered vault kinematics were selected for analysis in the present study.Biomechanics and kinematics are adequate to characterize the mechanics of causes and e ects of movements and variables of performance 12 .

The gymnastics table
For an adequate understanding, the studies describing the characteristics and predictors of performance in vaults were grouped variables.e dependent variables were the vault group (group one to ve) and body posture (tucked, picked or extended), as during vault 2nd ight phase it is another factor of differentiating and increasing complexity and vault value.The independent variables were the gender (male or female), category (seniors, juniors or beginners) and technical level (Olympic, World Championship, international or national).Some studies refer to the former horse used for vault.ey were included to allow observing the interdependence and relations among vault phases.e table vault is composed by a sequence of complex movements and is presented on male and female competitions [1][2]20 . As sown in

Results and discussion
determine the variables which can lead to performance improvement or score increase 6 .
Besides being recognized as empiric by great part of scienti c community, importance of such variables, most of the studies are descriptive, some are comparative among vault parameters to the nal score 5,14 .ere are few studies comparing the main variables in the vault event [15][16] , in special over di erent vault groups, in which the biomechanical factor is di erent 17 .It is believed that the kinematic variables of vault may vary according to the vault group, gender or technical level, but still lack of knowledge about the real di erences among vault groups, mainly when considering direct methods of measuring [18][19] .Sport coaches naturally want the best for their athletes to help them improve performance and reduce their risk of injury 4,6 .
After these considerations, the question arises from this scenario: what are the main parameters or vault phases that should be considered about gymnastics table vault?Are there essential variables which predict vault performance?Do the kinematic variables of vault vary over vault group, gender or technical level?e aim of this study is to present comprehensive information about the movement patterns of table vault, discuss the most relevant kinematic variables of vault performance and point out lacking points in research about this gymnastics event.
FIGURE 2, each vault can be divided into seven phases: 1) running; 2) jumping on springboard; 3) springboard support; 4) rst ight phase; 5) table support; 6) second ight phase and 7) landing 5,17,[21][22][23] .e vaults may be categorized in: a) continuous rotation (were the movement rotations happen on the gymnast transversal plane) handspring and Yurchenko; and b) change of direction, which the movement rotation axis of the 2nd ight is reverted in relation to the rst ight 25 .us, the main rst ight groups can be grouped in handspring, Tsukahara and Yurchenko 5,26 .
Within the 40 studies we have found, 18 studies (45%) described handspring group, four studies (10%) described Yurchenko group and two (5%) described Tsukahara group.No studies were found about vaults from group VI or V.One reason for it could be because the entry for these groups are performed with ½ turn or more in the 1st ight phase, so they are more complex to be performed with similar vault values as the other groups.Besides, the number of codi ed vaults for group IV and V is only half of the number of codi ed group I, and two thirds of group II vaults, containing less options for a vault that best t for a gymnast, considering the best vault values and penalties applicable.
Vault preparation occurs during running to springboard.e gymnast runs to increase the kinetic energy and increase the mechanical energy to the linear and angular rotations to be performed on the vault 2nd ight 16 .Following, after the contact and leave the springboard, the 1st ight is the displacement with the feet from springboard to the hands contacting the table.After the 1st ight, the contact table phase begins with the preparation for the 2nd ight.On 2nd ight, the gymnast performs rotations and get ready for the vault nal phase, which is the landing 16,27 .Vault lasts about two seconds of running, 0.1 s of springboard contact, 0.2 s of 1st ight and table contact, and one second of 2nd ight 28 .
The biomechanical characteristics that limits vaulting performance are related to the execution velocity, linear and angular body segments positions 24 and the vault phases duration 5,27 (described in FIGURE 1).e score attributed by a judge is highly related with the 1st ight duration, 2nd ight duration and height peak 23,29 ; while for T 21 the centre of mass (CM) horizontal displacement reach at 2nd ight peak would be the best predictor of judges' scores.To explain the relation between biomechanical parameters and vault values of di erent men's vault groups, A 24 applied a mathematical model to explain the nal phase (2nd ight) of vault.Vaulting performance depends on: CM position and height in final phase; 1st flight mechanical parameters during table contact; base of table spring properties; segments acceleration and torques between gymnast and table 30 ; strength, exibility and acceleration 31 .
However, S 32 determined important mechanical variables for optimal vault performance: variation of hand placement, reaction forces at hand support phase, minimal distance between body CM and the edges of the table, minimal and maximum distances between body and the edge of the table while crossing the apparatus, position at which the gymnast hits the vaulting board, distance of the vaulting board, and landing distance behind the table.
Hetch vault (group 1 handspring -reverse rotation on 2nd ight) was found in three (11%) studies.It was a compulsory vault in Men's Artistic Gymnastics during the Olympic cycle 1993-1996.e Hecht vault required a low trajectory of CM during preight, with a low vertical CM velocity and low angular velocity of the body at horse contact 33 .In contrast, the optimum handspring somersault required a high pre-ight trajectory, with a high angular velocity of the body and a high vertical velocity at horse contact 33 .
is is useful for technical development considerations when learning from Hecht to handspring vaults.
Hetch vault is an unusual vault in gymnastics [34][35] .Unusual for elite competitions because it is not coded anymore 1 , but it is considered the rst vault e running approach is preliminary phase that allows gymnast to reach peak horizontal velocity at jumping, what will be relevant for the next phases 44 .It is when the gymnast accelerates towards the table until the last movement before springboard contact.Some studies about vault biomechanics 25,29,45 had shown that as higher velocity peak is; more favourable is the development of propulsion to reach enough height and distance for 2nd ight rotations.Furthermore, there are many studies reporting successful vault performances such as run speed, maximum speed on springboard, 1st ight and 2nd ight position 8,17,20,23,29,32,44 .
For kinematics comparisons between the actual table and horse in vault, the running approach and springboard contact characteristics remained unchanged, as equipment modi cations did not change gymnast performance in these initial phases 13 .An analysis of men's and women's vault showed that during ten years the running approach velocity have increased, except for Yurtchenko group vault 44 .For those authors, the technical improvement of gymnastics during these ten years led a rise of the vault values, what means increasing the number of rotations and the complexity of body positions, in uencing on large velocity necessities 44 .Yurtchenko characteristics appear to be a factor limiting velocity, as round o entry requires more precise movements than jumping straightforward over the springboard.
Technical level of gymnast can determine the running approach acceleration to springboard.

Approach running
for beginners.Contact phase were studied and shoulder angles were emphasized to build models to understand the performance of Hetch vault 35 .Studies about juniors or beginners categories were found, and the Hetch vault would be a good example of search for any kinematics variable di erences from juniors to seniors, over an identical skill.Another paper advance on the relation between wrist and shoulder angles on junior female handspring vaults 36 .
ese comparisons would allow more knowledge about the common gymnast's errors and how to develop the vault technical progressions.
Optimization studies were applied to optimize performance scores for vaults with xed rotation potential [37][38][39] .e increase in height of 0.4 m between real condition (2.7 m) and optimum simulation (3.1 m) may seem rather high but is consistent with the heights reached in elite performances of handspring double front somersault (Roche) vaults (3.0 ± 0.1 m) which requires similar angular momentum 29,39 .
For Kasamatsu and Tsukahara vaults, horizontal CM velocity decreased, vertical CM velocity increased, and angular momentum was produced in the board contact phase.In addition, horizontal and vertical velocity decreased in the vault contact phase.However, no di erence was observed between both vaults.e contribution of upper limbs to angular momentum about the centre of mass was higher for Kasamatsu vault than that for Tsukahara vault at vault takeo 40 .e CM height contributes to vertical reception on landing, contributing with improved control.For high scores handsprings vaults, it was observed larger horizontal velocity and translational kinetic energy at takeo from the board, larger vertical velocity and greater amplitude on 2nd ight and superior landing performance 41 .
For the Roche (handspring plus double salto tucked forward) vault comparisons, gymnasts with high score in competition had: 1) greater height of body CM and a more fully extended body position at the horse take-o ; 2) greater height of body CM at the peak of post-ight, knee release, and touchdown on the mat; 3) greater horizontal and vertical displacements of body CM, greater somersaulting rotation, and longer time from the knee release to mat touchdown; and 4) markedly smaller landing point deductions 29 .
Modelling handspring was found with the former horse used for vault 42 and for the current table 39,43 , while was not found for other vault groups.It was veri ed that changing the apparatus from horse to table has changed handspring vertical take-o velocity 13 .But no studies were found regarding kinematics changes of other vaults.
Č et al. 17 presented biomechanical characteristics of vault and the most important factors for a successful vault jump.ese factors included morphologic characteristics, run velocity, length of ight on the springboard, duration of board contact, position of feet from springboard edge, duration of 1st ight phase, duration of support on table phase, duration of 2nd ight phase height of jump, distance from take-o 2nd ight phase, and landing.
Within the 40 studies found, only 13 (32%) compared vault groups.e following vault phases are depicted for a deeper understanding of its importance regarding to di erent vault groups.e descriptions of principles can be used to improve the application of biomechanics in the qualitative analysis of sport technique 4 .e jump on springboard starts when a gymnast jumps from the running track, after the last approaching step.Its objective is to transmit the impulse produced on running and on springboard to 1s and 2nd ight phases 10 .e energy provided from this approach will be redirected to the table by the springboard action 27 .At this instant it is important the gymnast posture, force generated by the gymnast, where this force is applied over the springboard, the velocity acquired and how the energy will be transferred 15,27,[46][47] .
When gymnast's feet contact the springboard with foot, the ground reaction force peak is around ten times the body weight 48 .ere is any factor related to the other phases that influence the Springboard contact springboard contact (vertical velocity, horizontal velocity and entrance angle), except the approach running 46,49 .However, the springboard support phase can in uence the subsequent phases [15][16] .
e position at which gymnasts hit the vaulting board is also important.Considering the handspring vault, jumping over the distal part of the springboard reduces more the gymnast horizontal velocity than jumping over the middle part 32 .In addition, the horizontal velocity of impacts was 18% higher over the distal part of the springboard, contributing more to the inversion of the gymnast due to larger horizontal velocity on anteroposterior direction 27 .
is consideration is important as the developing categories of gymnasts who do not have enough power to springboard should precisely jump over the springboard distal part to achieve the handspring vault.Moreover, the handspring group is one of the most challenging vaults for gymnasts who are as tall as the table height, and are passive to fall over the table with their back.One rule adjustment in Brazil is to allow one springboard to be place over another for beginners' categories, lowering the di erence between table and gymnast height and improving the propulsion 3 .Considering Tsukahara group, for example, the lateral hand position base is larger over the table, facilitating the small gymnast to pass over the table, besides allowing gymnasts to have visual contact during all vault phases, facilitating any skill corrections needed.Any of the found research relates table and gymnasts height to model the minimal kinematics parameters required to pass over the table, what would be useful for coaching purposes.Just one paper 31 associated training and kinematics variables in initial gymnasts categories (11-13 years old).
Another study analysing men's and women's vault kinematic parameters associated springboard contact and vault performance 15 .Women reached the springboard contact with lower entrance angle than men.By reducing 7% of horizontal or vertical velocity on springboard, it would reduce respectively by 13% and 25% of the distance on 2nd ight 15 .Because 2nd flight distance is one parameter evaluated by judges 1-2 , the entrance velocity over the springboard can in uence gymnast nal score 15 .
e distance of vaulting board 32 and high take-o velocity was directly related to judge's score 26 .e rst ight phase starts at the rst instant gymnast takes o the springboard until contact the V et al. 20 analyzed the running velocity of the last ten steps from the nalist gymnasts of the world championship (elite) and of the world cup (high level).In the last ten steps, gymnasts increase progressively velocity and reach the peak in the last step, being the elite (9.95 m/s) faster than high level (8.57m/s) gymnasts.erefore, elite gymnasts are more prepared to perform better vaults, due to larger nal velocity and impulse, better adjustment and running precision 20 .
All vaults of Stuttgart World championship had the running approach analysed, and velocity patterns were depicted accordingly vault group and gender.Handspring vaults had shown larger mean velocities, followed by Tsukahara and Yurchenko group vaults.Men were faster than women (handspring: 8.3 m/s versus 7.7 m/s; Tsukahara: 8.2 m/s versus 7.5 m/s), except for Yurchenko vaults (7.3 m/s for both genders).
ese di erences on running velocities may occur due to interaction of lower table height and lower vault value (number of rotations and body position) for women competition.e decreasing acceleration pattern during running was inversely proportional to velocity increase, aiming to target springboard.Considering the number of steps as a scale to estimate gymnast velocity 20 or distance 44 peak velocity occurs close to springboard, suggesting that larger velocity facilitates the subsequent execution of 1st ight.
An increased necessity of running acceleration is related to vault score, and if there is an error during approaching, hardly it can be corrected 26 .Generally, gymnast builds up kinetic energy during a sprint and that energy is partitioned into linear and angular momentum during springboard phase.These moments dictate the linear and angular momentum carried into the vaulting table 24 .

First fl ight phase
table.Its aim is to displace body from springboard to the table, promoting velocity and optimum entrance angles for the 2nd ight 5,16,30 .On the 1st ight phase, it is de ned the vault group related to its rotation, by maintaining the same direction to contact the table (handspring and Yurtchenko) or by changing the direction (Tsukahara) 18,30 .D et al. 11 monitored women hips kinematics in the main vault phases of di erent group vaults.e rst ight mean acceleration was: for Tsukahara piked (group 2) 17.09 m/s 2 , for Yurchenko stretched salto backward (group 3) 19.02 m/s 2 and for Handspring tucked salto forward (group 1) 21.83 m/ s 2 , showing that for junior gymnasts, the vault group can in uence the rst ight acceleration 11 .
In Tsukahara vault group, there is a chance that gymnast touches the table with one hand before than another, this also might be a reason for the larger time of support 19 . is fact assists gymnast to complete a turn of up to 180°.e duration of 2nd ight was larger for handspring, compared to Tsukahara group vault.However, the body position was not considered, what could in uence in these results.
K and J 30 investigated the variations of body entrance angle on 1st ight (as consequence of segments angular position variation) or angular moment on 1st flight (by segment angular velocity variation) would a ect vault performance, understanding the posture of rotations and the 2nd ight phase.It was analyzed the vaults performance of women's elite gymnasts, according to international judges observations and a model optimal vault was developed.is model had shown that when the angle body (entrance) is kept low during table contact, the angular momentum of 1st ight increases, with incoming earns on support phase, producing e cient vaults.erefore, the increase only in angular momentum to improve performance no 2nd ight may not happen due to the highly increase of velocity angular required.Similarly, higher body angles on contact were unattainable.A rise of CM on takeo of table was essential to reach height and distance su cient on 2nd ight.To compensate such factors, observed that, although as gymnasts lower angle body optimum, they increases partially CM rise and, mainly, velocity acquired, what provided larger height on 2nd ight.
Similarly, Y et al. 47 analyzed elite gymnasts vault from Canadian national championships to establish how the characteristics of 1st ight determine 2nd ight performance.ey found that peak height of CM on 2nd ight was correlated to CM vertical velocity on contact with the table; rotation velocity of body was correlated with shoulder angle on instant of support phase begin, and that the nal result of vault, judges scores, were correlated with a height peak of CM during 2nd ight.Since 1st ight performance limits of 2nd ight performance, the 1st ight must occur in an e cient manner.us, as larger the velocity is acquired a rise of CM during 1st ight and entrance angle, as better the nal performance of gymnast will be improved 30,47 .
Considering velocity, Y et al. 47 studied how 1st flight vault influences 2nd flight by means of vertical and horizontal velocity on vault Hetch and handspring vault.ey have found that gymnasts that performed vault Hetch have shown horizontal velocity of 5.56 m/s and vertical velocity of 3.38 m/s, while those performing vault handspring have shown horizontal velocity of 5.31 m/s and vertical velocity of 3.76 m/s.During table contact, the gymnast interacts with the table to further re ne post ight linear and angular momentum requirements, to achieve the vault's desired distance, height and rotations 24 .e simulations presented in handspring double salto 43 demonstrated that changes in horizontal velocity and contact technique both have an in uence on post-ight rotation potential.is nd reinforces that increasing horizontal approach velocity would improve performance 25 .S 32 determined mechanical variables important for optimal vault performance: variability of hand position, reaction force during the support phase of the hands, minimal distance between body CM and the far edge of the table while crossing the table, minimal and maximum distances between body and the far edge of the table while crossing the apparatus.e morphologic characteristics are important factors for a successful vault jump 24 .is is functional for beginners.It is usual to nd gymnasts smaller than the vault table, without enough power to proper 2nd ight over the table.Depending how far from the table's edge gymnasts place their hands, more susceptible they are to fall over the table, what characterize invalid vault (score will be zero), besides letting then to risk of injuries.e arms are in line with the torso at table touchdown and so the gymnast would need to modify his technique in order to achieve maximal rotation potential.Increasing both vertical velocity and angular momentum at table touchdown will improve performance 43 .
when a gymnast lands softly, knees should not be bent to lower body momentum of inertia, because lowering momentum of inertia increases angular velocity, and the movement became faster, leading to additional steps during landing.
In brief, the approach running is in uenced by the vault group, gender 20 and technical level 26,44 .Distance of springboard to table was investigated by only one paper 49 on handspring vault, focusing on how the distance can in uence the approach running.Nonetheless, other kinematics variables were di erent in other vault phases for expert German gymnasts.Changing the springboard distance to table by only 0.10 m a ected how far gymnasts' wrists were to back edge of the vaulting table and the take-o angle 49 .Further studies would help on improving other vault group performance, for beginner's categories and intermediate vault values as well, within an immediate possibility of changing vaulting parameters.
First ight duration was di erent according to the vault group 11,47 .No additional studies were found comparing gender or technical level di erences.Although vertical velocity was similar in all phases, the mechanical needs are unequal, suggesting that the propulsion on vault is in uenced by vault group, constraining the angular parameters as source of variation 19 .Second ight duration were di erent according to the vault group 19,30,40 ; and technical level 21,29,54 .No other studies were found comparing gender di erences or relating vault and table height.
Body posture (tucked, picked or extended) during 2nd ight phase, a ects vault value and vault complexity, even though it was not the focus of evaluation of most studies found 43 .It is expected that by changing body posture would e ect on kinematics.For example, the same vault in the code of points has more value added according to the body posture adopted on 2nd ight [1][2] .
From five vault groups in the code of Points, we grouped them into three main vault groups: handspring, Tsukahara and Yurchenko.A kinematic variable depends upon the vault type.Handspring is a direct vault, without turns before de 2nd ight. is means that less precision is needed to springboard for table contact, allowing larger velocity and height achieved on 2nd ight.
Tsukahara is characterized by a body round off rotation in 1st flight, what mean loss of velocity compared to another group vaults.Hands placement makes the gymnast to spend more time over the table, lowering the 2nd flight height.However, more vaults with higher score value are The 2nd flight phase starts immediately after the end of support phase and ends before gymnast reaches the landing mats with his feet.is is when gymnast has to maintain a body posture, showing or not rotations on longitudinal and or on transversal axis.According to the gymnastics Code of Points 1-2 , judges must consider on 2nd flight height and distance gymnast achieved from the table, as criteria for applying penalties.An excellent 2nd ight depends on the characteristics of previous phases 20-21, 23, 29, 46 .As faster is the last table approach, larger is the potential to generate impulse no vault.Y et al. 39 found that increasing touchdown velocity and angular momentum lead to additional 2nd ight height and therefore to additional rotation potential.
e fast and intense impact on springboard and the push with upper limbs on support phase might increase height of 2nd ight, due to increase of kinetic energy.With larger height in 2nd ight, more time is available to complex rotations on transversal or longitudinal axis 20 , facilitating gymnast's control of subsequent phase.
e landing is determined when gymnast reaches the mat and nishes the vault.It is fundamental evaluation criteria for judges and in uenced by performance of 1st and 2nd ights.While the 1st ight depends of contact phase with springboard, the execution of landing depends on each of precedent phases and re ect the overall quality of vault 29 .In this phase, gymnast must reach the mat sticking on it, without more steps or jumps, and CM must be over the support base and any step, instability or oscillations of arm position may result in judges' deductions [1][2]50 .
All kinetic energy stored is lost on the landing mat and on gymnast body, and the impact magnitude depends about height of ight and complexity of movement 51 .For a safe landing, without more steps or fall, it is important that the gymnast reach the mat with a correct posture, increasing the chances to "stick" the landing (without moving) and allowing the adequate use of ground reaction force to hold rotation with lower muscular e ort 24,[50][51][52] .
For M

51
, knee angle de nes if the landing is stable or not.If the gymnast show knee angles over 63°, means that the landing was wrong, and penalties are applied.Studies describing the main landing errors and variables that would in uence that errors 53 suggest soft landings are the most e cient, while rigid and deep landings may imply larger errors.Even
found in Tsukahara group than in Yurchenko group.Furthermore, Tsukahara vault group can be easier developed with beginners because the visual contact over the table.
Yurchenko is characterized by round off on springboard, what induces less velocity than handspring, but it uses more the springboard mechanical energy than Tsukahara, because is direct (no turns before 2nd ight).As handspring, simultaneous hand placement allows base to gymnast reach 2nd ight higher than Tsukahara group vaults.
Most of studies are descriptive, and only the recent studies are comparing the di erences of some high complexity vaults.Still to be researched the vault kinematic variables focusing di erences among vault group, body posture on 2nd ight, gender and technical level.ere is a lack of information about performance within low and intermediary score vaults, for initial categories in both genders, in order to help gymnast development.In other gymnastics events, for example, studies regard about skill progressions [55][56] , a closer source of knowledge for coaching biomechanics interface 6 .