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Performance Analysis of the female Yurchenko layout on
the table vault
Gabriella Penitente, PhD
Academy of Sport and Physical Activity, Sport Department, Faculty of Health & Wellbeing,
Sheffield Hallam University, UK
Abstract
This study proposed a performance analysis method of the gymnastics vault
that accounts for the open-score judging system. The model aims to identify the
mechanical faults that explain the deductions assigned by judges relative to the
on-board and pre-flight phases of the Yurchenko-style vault. In the attempt to
identify the weakness of technique and to diagnose the likely causes of poor
performance, an extensive analysis was undertaken using a deterministic
model. Twelve Yurchenko layout vaults with and without full twist in the post-
flight performed by female gymnasts during the team competition of the 2006
Italian Championship were filmed with three cameras operating at 100 Hz.
Spearman`s correlation coefficient was used to measure the strength of the
relationship between the mechanical variables of the model and the judges`
point deductions. Significant correlations indicated that the loss of points
depended mostly on the range of flexion of the shoulders at the impact with
board, a disproportionate flexion of the knees during the on-board phase and
the inaccuracy of the pre-flight. Comparing results with existing literature
large differences were noticed, this underlines the need for up to date
information on the modern vaulting techniques.
Keywords: Gymnastics Vault, Handspring, Kinematics, Yurchenko, Performance
model
1. Introduction
In gymnastics the vault is the only apparatus that lends itself to an in depth performance
analysis, as it involves the execution of a single acrobatic element (Prassas et al., 2006). The
deterministic model approach has been utilized frequently in vaulting performance analysis
(Prassas et al., 2006; Lees, 2002; Chow and Knudson, 2011). It has been used by Takei to
investigate several vault styles performed during competitions in the late `80s and `90s
(Takei, 1989; Takei, 1990; Takei, 1991a; Takei, 1991b; Takei, 1998; Takei and Kim, 1992;
Takei, 2007; Takei at al. 2000) by measuring correlations between crucial variables and the
score assigned by judges.
Biomechanists have extensively investigated vault performances (Prassas et al., 2006; Sands
et al. 2003). However, the reduced number and often outdated investigations conducted on
data collected during competition situations ((Takei, 1989; Takei, 1990; Takei, 1991a; Takei,
1991b; Takei, 1998; Takei and Kim, 1992; Takei, 2007; Takei at al. 2000; Known et al. 1990;
Nelson et al., 1985; Ragheb and Fortney, 1988) makes the actual body of knowledge lacking
International Journal of Performance Analysis in Sport
2014, 14, 84-97.
84
in external validity. In the last decade the International Gymnastics Federation (FGI)
approved a number of changes with the specific intend to re-modernize the profile of the
discipline. The first major change came in 2001 with the replacement of the `horse` with the
`table` vault apparatus. The wider surface of the table encouraged female gymnasts to
perform vaults from the Yurchenko-style group (round-off entry vaults) (Uzunov, 2010). The
second change, in 2004, was the introduction of the `open-end` scoring system. Today
gymnasts receive ‘awarded scores’ by two panels of judges; one detects the difficulty score
(D-score), determined through the Code of Points (CP); the other assigns the execution score
(E-score) that evaluates the quality of the technical performance. The base E-score is 10.00
and judges deduct points that reflect pure technical faults. It is recognized that with this
scoring system the impact that the deductions assigned for technical faults have on the final
score, has become particularly important for the vault event (van Deusen, 2011). The
aforementioned changes created the urgency to inform coaches with updated knowledge and
understanding of the modern vault technique and its performance analysis. This urgency was
already acknowledged by McNitt-Gray et al. in 2000, when on the basis of their analysis on
the Sydney Olympics Games horse vault performances, they concluded that increasing the
length of the vault apparatus by a factor of three would require female gymnasts to adapt
either their pre-flight or post-flight mechanics. Moreover, their investigation showed that
with this change in length, many of gymnasts would fail to clear the apparatus and hit the
table, 25% with their head and 35% with their feet.
The only biomechanical studies that analyzed Yurchenko vaults during competitions date
back to the Olympic Games in 1984 (Nelson and Gross, 1985; Ragheb and Fortney, 1988;
Fortney and McNitt-Gray, 1989) and in 1988 (Known et al. 1990); while a study from Elliot
and Mitchell in 1991 compared training drills with competition simulated trials. Although
more recent studies have been published on this vault style (Koh et al., 2003; Koh and
Jennings, 2007; Koh and Jennings, 2003), not a single one provides up to date information
about the execution on the table apparatus, and during competition situations.
The primary aim of this study was to renovate Takei`s deterministic model to better
accommodate the modern scoring system. Further adjustment of Takei`s model was
necessary to allow a three-dimensional (3D) analysis of the vault on the table.
The analysis of the pre-flight and on-board phases of Yurchenko vaults performed by female
elite gymnasts during an official competition was used to demonstrate a practical application
of the analysis. Similarly to Takei`s model, the proposed analyses aimed to identify the
influence of mechanical faults in the earlier phases of the vaults on the judges` point
deductions. In the light of past investigations, the study also identified key changes in the
modern Yurchenko vaults technique.
2. Methods
2.1. Data Collection
Data was collected during a `Serie A` female team competition in the 2006 Italian
Championship. Eight teams were admitted in this competition, two gymnasts from each team
performed on each apparatus and, in accordance with the FGI regulations, each gymnast
performed one vault.
Ethical approval was granted, and approval of the Italian Gymnastic Federation was obtained.
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All the twelve Yurchenko vaults performed during the competition were selected for the
analysis. These included five Yurchenko layout vaults with a full twist in the post-flight
(YUT) and, seven Yurchenko layout vaults (YUL) with a level of difficulty (D-score) of 5.00
and 4.40 points respectively (FGI, 2006). Both vaults include a round-off onto the board, a
back handspring onto the table (pre-flight) and a straight backward somersault (post-flight)
(Figure 1). The increased level of difficulty for the YUT is determined by the addition of a
full twist (full rotation around the longitudinal body axis) in the post-flight phase.
Figure 1 – Body positions at key instants of impact on the board, maximum flexion of the
knees and take-off from the board (on-board phase) and at the instant of impact on the table
(pre-flight phase) during the Yurchenko layout vault.
Three high-speed cameras (BASLER 610, 3CCD, 1Mpixel) synchronized via genlock were
instrumented around the vault podium, each filming at a nominal rate of 100 Hz, with the
angle between their optical axes set at approximately 120°. The x-axis (horizontal) of the 3D
reference system was directed along the runway, the z-axis (vertical) was orthogonal to the
floor, and the y axis (transversal) oriented orthogonal to the x-z plane. An eight points`
calibration cube of the dimension of 1.00x1.10x1.10 meters located in front of the table
instead of the board was used to scale pixels in meters. Each trial included the following
phases: on board, pre-flight, repulsion and post-flight. For the present study only the on-board
and pre-flight phases were taken into account. The instants of impact on the board (IMPB)
and on the table (IMPT) and the instant of take-off from the board (TKB) were identified
from the videos and used to define the on-board phase (between the IMPB and the TKB) and
the pre-flight phase (between the TKB and the IMPT).
The SIMI Motion System software was used to digitize approximately fifty frames of the
movies from the impact on the board to the impact on the table. The gymnasts’ body was
characterized by a 14-segment model (head, trunk, arms, forearms, hands, upper leg, lower
leg, and feet). The data were filtered with a low-pass second-order filter with a cut-off of 6Hz
(Jackson, 1979). The 3D location of the CM was computed using the Dempster’s
anthropometric parameters (1955).
2.2. Score Analysis
According to the CP of the FGI (2006) the `specific apparatus deductions` on the vault are
assigned during the pre-flight, repulsion and post-flight phases for poor technique associated
86
with insufficient height and distance in the post flight, and for lack in dynamic of the
execution. Judges evaluate errors based on specific criteria on a scale including small,
medium and large mistakes related with deductions of 0.1, 0.3 and 0.5 points. The deductions
associated to each of the four phases of the vault (pre-flight, table contact, post-flight and
landing) were calculated.
The CP established that the evaluation of the landing phase is based on the `general landing
penalties` rules common to every apparatus dismount element. Therefore, to better focus the
analysis on the penalties assigned for vault-specific faults, the landing phase was not
considered.
The final score of each gymnast was analyzed by a certified international judge involved in
the competition. The videos clips recorded from the same point of view of the judges’ panels,
confirmed that all the gymnasts performed at a standard consistent with level of difficulty
declared (D-score). Hence, E-deductions were calculated utilizing equation 1.1.
E-deductions = 10.00 – [Final score – D-score] 1.1
The E-deductions were further elaborated by subtracting the landing penalties including
steps, hops and landing performed outside the marked corridor (landing area). The residual E-
deductions score was then used to identify the `specific apparatus deductions` associated with
faults occurred during the post-flight phase. We will refer to this as `Partial E-deductions`.
Partial E-deduction= [E-deductions – Landing deductions] 1.2
To focus the analysis on the most important part of the performance, the penalties assigned
during the post-flight phase were isolated by subtracting the pre-flight and on-table penalties.
We will refer to this variable as `Post-flight E-deductions`.
Post-flight E-deduction= [Partial E-deduction – Pre-flight deductions – On table deductions]
1.3
2.3. Vault Model
Takei`s deterministic model of the pre-flight and on-board vaulting phases (Takei, 1989;
Takei, 1990; Takei, 1991a; Takei, 1991b; Takei, 1998; Takei and Kim, 1992; Takei, 2007;
Takei at al. 2000) was used as baseline. Although the hierarchy of the variables as proposed
by Takei was not modified, kinematic variables relative to the transversal plane of motion
(i.e. horizontal, vertical and medio-lateral velocity) and relative angles of the body (i.e. knee
angle) were added into the model, while variables derived by inverse dynamic were excluded
as the gymnasts` body mass was not available. These modifications resulted in a model of the
vault suitable for the evaluation of norms related to the modern scoring system. The
kinematics variables included in the model are reported below.
The temporal data (a) expressed in seconds were used to determine the duration of the on-
board and pre-flight phase. The linear spatial data (b) measured in meters, included the
horizontal displacement of the CM on the board and during the pre-flight. The height of the
CM was measured at the instants of impact with the board and with the table (which
coincides with the peak of the pre-flight) and at the instant of take-off from the board. In
addition, other vertical displacement data were included, the height of the CM measured at
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the instant in which the CM reached the lowest point on the board; the upward displacement
of the CM during the on-board phase; the relative height of the CM on the board calculated as
difference between the height between the take-off from the board and the peak of the pre-
flight phase. The medio-lateral displacement of the CM during the pre-plight was also
reported. The linear velocities (c) were obtained by differentiating the linear displacements of
the CM. The horizontal, vertical and medio-lateral velocities at the impact and take-off from
the board, the resultant velocity at the take-off from the board were expressed in m/s. The
angular spatial data (d) relative to the absolute body angle (the angle between the horizontal
line and the line passing through the CM and the toes at impact with the board and take-off
from the board), the relative flex-extension angles of hips, knees and shoulders at the impact
and take-off from the board and maximum flexion of the knees on the board were measured
in degrees (°); the average value between left and right limbs was used for the analysis. The
angular velocities (e) were calculated by differentiating the angular displacement relative to
the body angle at the impact and take-off from the board, and during the on-board phase. The
angular velocity of the hip and the shoulder in the on-board phase were also calculated and
expressed in rad/s.
The kinematic variables of the on-board and pre-flight phases were organized in a flowchart
diagram including six levels (Figure 2 and 3). For the first stage of the analysis, the mean
Partial E-deductions were placed at the first level of the model to identify the impact that the
on-board and pre-flight phase technique have on the overall performance. Subsequently, the
mean Post-flight E-deductions were placed at the first level of the model to evaluate the
relation between faults in the preliminary phases and deductions assigned in the post-flight.
2.4. Data Analysis
Statistical analysis was performed with SPSS version 17.0 (SPSS Inc., Chicago, Illinois). The
normality in distribution was assessed by means the Shapiro-Wilk test (p = 0.05). Due to
failure of the normality test of some kinematic variables and considering the deductions
assigned by judges as an ordinal variable, non-parametric statistical methods were used for
the analysis of the data. To verify the biomechanical similarity between the two types of
Yurchenko vaults, all the kinematic variables were tested using the Mann –Whitney test (p =
0.05).
The six level model was used to analyze first, the correlations between the selected
mechanical variables and the E-deduction relative to the `Partial E-deductions` and second, to
the `Post-flight E-deduction`. Spearman’s rank rho correlation coefficient (rs) was used to
assess the variables-deductions relationship. Due to the large number of variables that can
potentially contribute to explain the variability if the judges’ deductions`, the p critical value
was set at 0.065 (Takei, 2007). The coefficient of determination (rs –squared) was also
calculated.
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Figure 2 - Six- levels deterministic model. The model shows the correlations between the
Partial E-Deductions assigned by judges 'and the mechanical variables characterizing the on-
board and pre-flight phases.
89
Figure 3 - Six- levels deterministic model. The model shows the correlations between the
Post-flight E-Deductions assigned by judges 'and the mechanical variables characterizing the
on-board and pre-flight phases.
90
3. Results
The maximum theoretical rate of deductions associated to each of the four phases of the vault
(pre-flight, table contact, post-flight and landing) is reported in percentage in Figure 4.
Figure 4 – Calculated maximum theoretical rate of deductions associated to each phase of the
vault by the Code of Points.
These calculations show that the post-flight phase is the most important phase of the vault.
More than 50% of the judges` evaluation focussed on this phase.
Tables 1 to 3 report the descriptive statistics relative to the mechanical variables selected for
the analysis.
Table 1. Temporal and Linear Displacement data relative to the CM
YUT
YUL
On-Board Time (s)
0.154 (0.11)
0.146 (0.01)
Pre-Flight Time (s)
0.126 (0.02)
0.150 (0.03)
On-Board Horizontal Displacement (m)
0.72 (0.08)
0.63 (0.05)
Pre-Flight Horizontal Displacement (m)
0.52 (0.08)
0.60 (0.10)
On-Board Minimum Height (m)
-0.016 (0.01)
0.012 (0)
Board Take-Off Relative Height (m)
0.288 (0.02)
0.283 (0.04)
Pre-Flight Peak (m)
1.61 (0.04)
1.63 (0.09)
Pre-Flight Medio-lateral Displacement (m)
0.011 (0.01)
0.029 (0.02)
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Table 2. Angular position of the body, hips, shoulders and knees at the instants of impact and
take-off from the board.
YUT
YUL
Body Angle Board Impact (°)
60 (0.5)
61 (2.1)
Body Angle Board Take-Off (°)
97 (2.4)
96 (2.1)
Shoulder Angle Board Impact (°)
69 (10.7)
66 (11)
Shoulder Angle Board Take-Off (°)
198 (9)
198 (6.2)
Hip Angle Board Impact (°)
124 (10)
116 (8)
Hip Angle Board Take-Off (°)
203 (6)
194 (9)
Knee Angle Board Impact (°)
146 (7)
141 (9)
Knee Angle Board Take-Off (°)
156 (5)
159 (6)
Knee Maximum Flexion on-Board (°)
132 (7)
130 (3)
Table 3. Linear and angular velocities relative to the CM at the instants of impact and take off
from the board and during the on-board phase
YUT
YUL
Board Impact Vertical Velocity (m/s)
-0.56 (0.14)
-0.65 (0.17)
Board Impact Horizontal Velocity (m/s)
5.27 (0.6)
5.17 (0.33)
Board Take-Off Vertical Velocity (m/s)
3.84 (0.11)
3.71 (0.2)
Board Take-Off Horizontal Velocity (m/s)
4.14 (0.46)
3.98 (0.27)
On-Board Change of Vertical Velocity (m/s)
4.41 (0.20)
4.36 (0.15)
On-Board Change of Horizontal Velocity (m/s)
-1.12 (0.86)
-1.19 (0.42)
Board Impact Medio-lateral Velocity (m/s)
0.08 (0.2)
0.08 (0.1)
Board Take-Off Medio-Lateral Velocity (m/s)
0.12 (0.2)
0.07 (0.1)
Board Impact Body Angular Velocity (rad/s)
3.3 (0.6)
3.5 (0.6)
Board Take Off Body Angular Velocity (rad/s)
3.3 (0.3)
2.6 (0.3)
The Mann-Whitney test confirmed that the mechanical differences relative to the on-board
and pre-flight phases of the two Yurchenko vaults layout, one with full twist (YUT) and one
without twist (YUL), in the post-flight were not significant. Therefore, the twelve trails were
compounded in the successive correlation analysis.
3.1. Model
Following the deterministic model, after the Partial E-deductions (1st level), in the 2nd level
two crucial variables were identified, the angular distance and the trajectory of the CM during
the pre-flight. These two variables were not measured due to the difficulty to synthetically
represent them with a single value; so the correlations between the kinematics variables of the
on-board and pre-flight phases and the penalties assigned by judges resulted statistically
significant are presented from the 3rd level of the model.
The Partial E-deductions significantly correlated with the horizontal velocity of the CM at the
impact with the board (rs = - 0.594, p = 0.042), 5th level of the model. This indicated that
gymnasts with a greater horizontal velocity at the impact with the board were less penalized.
The coefficient of determination (rs –squared) indicated that 35.3% of the variance in the
Partial E-deductions was explained by the horizontal velocity at the impact with the board.
At the 6th level of the model, the Spearman`s rho revealed a significant correlation between
the Partial E-deductions and the maximum flexion of the knees on the board (rs = 0.571, p =
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0.052). The gymnasts that during the downward motion of the on-board phase flexed their
knees less received lower score deductions. rs –Squared indicated that 32.7% of the variance
in the Partial E-deductions was accounted for by the maximum flexion of the knees reached
when in contact with board.
The correlation between the biomechanical variables of the model and the `Post-Flight E-
deductions` (1st level) revealed more critical variables Among the variables determinant for
the angular displacement of the CM at the 3rd level of the model, the duration of the pre-flight
was significantly correlated with the penalties assigned by judges in the post-flight (rs =
0.623; p = 0.03). This positive correlation meant that the increase in the duration of the pre-
flight phase increased the penalties assigned by judges in the post-flight. 38.8% of the
variance in the post-flight penalties was explained by the duration of the pre-flight. At the 4th
level the angular position of the hip at the take-off from the board revealed a significant
correlation (rs = - 0.622; p = 0.031). Thus, the gymnasts who took off from the board with the
hips more extended were less penalized during the post-flight. rs-squared showed that 38.7%
of the variance in the post-flight deductions was accounted for by the angular position of the
hips at the take-off from the board.
Regarding the variables that determine the trajectory of the CM during the pre-flight, the time
that the gymnasts spent in contact with the board, at the 6th level of the model, was
significantly correlated with score deductions (rs = -0.57; p = 0.53). A longer time on the
board was associated with less penalties assigned in the post-flight and 28% of the variance
in the post-flight penalties was explained by the duration of the on-board phase.
Also at level 6, the penalties of the post-flight significantly correlated with the vertical and
horizontal displacement of the CM during the pre-flight (rs = 0.564; p = 0.056 and rs = 0.586;
p = 0.045, respectively). This correlation showed that the gymnasts who performed the pre-
flight with a larger vertical and horizontal displacement were penalized more in the
successive post-flight. The coefficient of determination showed that these two variables
explained respectively 31.9% and 34.3% of the variance in the post-flight deductions
assigned.
4. Discussions
The results from the study represented a 3D kinematics performance analysis model of the
earlier phases of the YUT and YUL vault executed by elite female gymnasts in a competition
situation.
The statistical analysis showed that the on-board and pre-flight phases were similar and that
the mechanical differences between the YUT and the YUL were not significant.
The comparison of results with previous Yurchenko analysis studies confirmed that the
modern technique is considerable changed.
Know, Fortney and Shin (1990) found a significant difference in the duration of the on-board
phase between the two vaults, with the YUT having a shorter time on-board than the YUL
(YUT 0.148 s, YUL 0.157 s). It must be considered that the current study was undertaken in a
modernised era of female gymnastics; the boards are from fibreglass rather than wood,
gymnasts are better prepared and physically stronger and the vaulting apparatus changed
from horse to a table.
93
In the past the distance between the board and the horse vault was measured to avoid missing
contact with the apparatus. The increased vaulting surface (from the horse to the table) has
given gymnasts a larger range for the length of their pre-flight. As the results showed in
Table 1 the pre-flight of modern gymnasts has actually shortened (Ragheb and Fortney, 1988;
Elliot and Mitchell, 1991) on the table rather than increased.
Results relative to the linear velocities of the CM confirmed the aforementioned changed in
execution strategies. The changes in horizontal velocity between the impact and the take-off
from the board in this study showed a more efficient on-board action. The loss in horizontal
velocity while on the board was, in fact, reduced in comparison to the past (Know, Fortney
and Shin, 1990).
The analyses of the vertical velocities at the take-off from the board showed modern
technique is more effective, it was 0.3 m/s and 0.26 m/s higher when compared with the
results obtained by Know, Fortney and Shin (1990). The considerable lower vertical take-off
velocity reported by Elliot and Mitchell (1991) (2.7 m/s) might imply a less efficient
gymnast-board interaction in the past. Overall, now gymnasts are able to increase their
average vertical velocity on the board up to 4.41 m/s when performing the YUT (3.57 m/s in
the past – Known et al., 1990) and, 4.36 m/s when performing the YUL (3.62 m/s in the past -
Known et al., 1990).
A comparison of the angular kinematics of the shoulders at the take-off from the board
showed that the shoulders flexion is considerably higher (198°) than in the Elliot and
Mitchell`s study (160°) (1991). The increased shoulder angle might be interpreted as an
increased level of confidence in diving backward towards the table, instigated by the
increased vaulting surface.
Through the analysis of the deterministic model developed, it was possible to identify a
specific pattern of linear and angular kinematic variables that explain technical faults during
the on-board and pre-flight phases. This model was further used to understand the impact that
these faults had on the overall competition score and thus to clarify how poor performance in
the earlier phases determined points deductions in the post-flight.
In the first instant, it is possible to infer that a large flexion of the shoulders at the impact with
board combined with a too large flexion of the knees during the on-board phase caused
points` deductions. It is important to notice that while the excessive flexion of the knees may
have a negative effect on the explosiveness of the `punch action`, the results obtained
demonstrated that the downward motion of the CM on the board is essential for a good
performance. In fact, to effectively use the board it is necessary to gain a sufficient level of
compression of its springs. A proper `punch action` technique characterized by a hollow body
position with the knees slightly bent, enables gymnasts to use the spring`s recoil to maximize
the transfer of power in to the successive phases. Although the angular velocity of the
shoulders did not appear to be a critical performance factor for these elite gymnasts, it is
important to notice that for less advanced performers, hitting the board with the upper limb
excessively flexed may compromise the swing action of the arms. This in turn, may decrease
the angular momentum necessary to generate the somersault rotation in the pre-flight (Koh
and Jennings, 2007).
The model consistently displays the interdependence between inaccuracies in the pre-flight
and deductions in the post-flight. In particular, a too long range, a too high peak and a too
94
long duration of the pre-flight were detrimental for the performance. It could be suggested
that gymnasts who `over-stretched` the pre-flight in an attempt to approach the far end of the
table as close as possible to ensure to clear the apparatus.. Results showed that gymnasts
should avoid to re-bound straight up resulting in a too high pre-flight. Instead, they should
generate more rotation to reach the table earlier and avoid point deductions in the post-flight.
There are two limitations that need to be acknowledged and addressed regarding the present
study. The first is the unavailability of body mass parameters of the gymnasts. It was not
possible to measure the gymnasts, due to the restrictions of the organization of the
competition. This precluded the opportunity to calculate crucial variables such as the angular
momentum and the momentum of inertia of the body. The second limitation is that the model
is used to analyse data from 2006, this means that innovations of the last 6 years regarding
the Yurchenko vault have not been integrated in the model.
5. Conclusions
In conclusion, this deterministic model of the YUT and YUL provided evidence that the
modern technique used by female gymnasts to perform the on-board and pre-flight phases is
considerable different from the past and that it is still evolving. The changes detected in the
study suggested that although it is important to recognize the valuable contribution of studies
conducted on the mechanics of horse vaulting, the existing information should be applied
with caution to the contemporary circumstances. Results from this study showed that
combined innovations and changes, the evolution of apparatuses and the introduction of the
`open-end` scoring system and the increased level of physical fitness reached today by female
gymnasts, demands further research on gymnastics vaulting.
Now that gymnasts can perform Yurchenko-style vault without the fear of missing the
apparatus after the pre-flight phase, it remains to further investigate how to optimize the path
of the pre-flight by identifying the ideal board to table distance in relation to gymnasts` body
size and gymnasts` physical strength characteristics.
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