Run-up Velocity Research Articles

KINEMATIC CHARACTERISTICS OF THE APPROACH RUN ON HANDSPRING VAULT BY HIGH LEVEL MALE GYMNASTS HIGH LEVEL MALE GYMNASTS

The approach run is a fundamental precondition for successful vault performance, as it enables the gymnast to develop maximum controlled horizontal velocity. The purpose of this study was to investigate the length, frequency, and velocity of steps during the run-up phase (approach run) in the execution of the handspring vault on the vaulting table. Nine high-level male artistic gymnasts, who performed the handspring vault under training conditions, volunteered to participate in the study. Five video cameras—four stationary and one scanning—were used to record the run-up phase, the hurdle step, and the take-off from the springboard. The gymnasts performed six trials of the handspring vault with a three-minute rest between each trial. Results showed that the final step was shorter than the penultimate step, and the penultimate step was longer than the preceding step. Additionally, the gymnasts demonstrated a gradual increase in their run-up velocity, a key requirement for a successful jump, up to the penultimate step. The average step frequency among gymnasts ranged from 3.20 to 4.88 steps per second, while the average step velocity across the six attempts was between 4.03 and 7.37 m/sec. Finally, a gradual increase in the gymnast’s velocity was observed up until the last step, with the final step being shorter than the penultimate step and the penultimate step being longer than the one before it.

Run-up velocity and jumping ground reaction force of Chinese female gymnasts

The run-up velocity and jumping ground reaction force directly influence gymnasts’ ability to perform more difficult manoeuvres and win competitions on vault. However, the variables influencing them among elite female gymnasts remain inadequately understood and warrant detailed investigation. This study aimed to analyse critical variables including run-up velocity and jumping ground reaction force, and to compare these factors across different vault types while further exploring the correlations among them. The study hypothesized that there are significant differences in run-up velocity and jumping ground reaction force across vaulting types, and that these differences will affect athletes’ performance. To test this hypothesis, the study analyzed data from performance tests on 16 elite Chinese female gymnasts, focusing on vaulting run-up velocity and jumping ground reaction force. Descriptive statistics were used to summarize the data, and binary logistic regression analysis was employed to investigate the relationships between the variables. The study found significant differences in interval run-up velocities between the Front handspring vaults and the Tsukahara vaults, particularly before the last 10 m (p = 0.04) and the last 5 m (p = 0.03). Specifically, the Front handspring vaults had higher velocities before the last 10 m, while the Tsukahara vaults had higher velocities within the last 5 m. Differences were also noted in the lengths of the penultimate (p = 0.03), last (p = 0.01), and hurdle steps (p = 0.04). The jumping ground reaction force showed a strong negative correlation with run-up velocity before the last 10 m (ρ = -0.469, p < 0.01) and the last 5 m (ρ = − 0.604, p < 0.01). However, no significant associations were found with the 25 m run-up velocity (p = 0.346). Significant differences were observed in the hip joint angle (p = 0.001) and the trunk-to-ground angle (p = 0.001), but not in the landing angle (p = 0.435) and take-off angle (p = 0.594) during the take-off phase. These findings suggest that revising the run-up rhythm and improving pedaling techniques could contribute to the successful performance of more difficult vaulting maneuvers for female elite gymnasts in China.

Influence of run-up velocity on cricket bowling

Influence of run-up velocity on cricket bowling

Kinematic Contribution to Javelin Velocity at Different Run-Up Velocities in Male Athletes.

In javelin training, many athletes improve their throwing technique by throwing from a slower run-up velocity than in competitions. However, whether the acquisition of javelin velocity in throwing from a slower run-up velocity is the same as in full run-up throwing is unclear. The purpose of this study was to clarify the differences in the contribution of each movement to the javelin velocity caused by changes in the run-up velocity within an individual. Twelve collegiate male javelin throwers were included in this study. Athletes performed two types of throws: one-cross throwing (Cross) and full run-up throwing (Run). The coordinates of reflective markers attached to the thrower's body and the javelin were recorded using an optical motion capture system. The percentage contribution of each joint movement to the javelin velocity was calculated and compared between Cross and Run. Cross had a lower contribution of trunk forward lean to forward and upward javelin velocities compared to Run. On the other hand, Cross had a higher contribution of trunk counter-clockwise rotation to forward and upward javelin velocities than Run. These results suggest that as the velocity of run-up changes within an individual, the acquisition of javelin velocity also changes.

Sex difference in soccer instep kicking

ABSTRACT We aimed to clarify the differences in soccer instep kicking dynamics between sex groups. The instep kicking of seven female (height: 160.3 ± 6.1 cm; mass: 54.3 ± 5.2 kg) and seven male (height: 173.0 ± 5.9 cm; mass: 70.0 ± 9.0 kg) players were recorded by a motion capture system (500 Hz). Joint moments of the kicking leg were computed and normalized by the body mass and height. Statistical parametric mapping was used to compare the entire kicking motion between the two groups. Significantly slower resultant ball velocity seen in female players was most likely explained by their significantly slower run-up velocity, shorter leg length and lower foot–ball velocity ratio. Female players exhibited significantly smaller knee joint moment in the latter part (80–86%) of kicking. Also, significantly smaller positive work done by knee extension moment and the ratio of work (knee extension/hip flexion) were found in female players. These results suggested that the suppressed knee extension moment action was identified as a key kinetic characteristic in the instep kicking of female players, and to compensate for this action, they more rely on the work due to hip flexion moment to execute the instep kicking.

Prediction of Jumping Distance Using Run-Up Velocity and Age for Female Long Jumpers

It is the flight distance which is approximately ninety percent of jump distance in long jump. On the other hand, there are many biomechanical factors that determine the flight distance and horizontal velocity is considered to be the most effective factor. The aim of this study was to create a jump distance estimation model based on run-up velocity that can practically be used by trainers. The research data was included 858 valid trials of 156 female Turkish long jumpers (ages: 17.8±3.4 years). According to the correlation results of the current study; a nonlinear regression model was used between the variables found to have the highest correlation (age, last 10 meter run-up velocity, jump distance). According to this model, 79.10% of the jump distance can be estimated with the variables of age and run-up velocity in the last ten meters. Developed to be used for female long jumpers at a broad performance level, this model may make it possible to make technical evaluations about whether the velocity, technique and strength of a female long jumper are stable. Keywords: long jump, velocity, age, prediction model

ECCENTRIC PEAK TORQUE OF THE KNEE FLEXORS AND EXTENSORS RELATES TO BACKWARD SOMERSAULT HEIGHT IN FEMALE JUNIOR ARTISTIC GYMNASTS

Artistic gymnastics consist of a high amount of jumping actions with rotations around one or more axes. To achieve an optimal flight height to perform the desired number of rotations, the movement pattern and the floor characteristics have to be concerted optimally. To account for the required leg stiffness to utilize the floor’s elasticity, the leg musculature has to generate high forces during the ground contact in an eccentric manner. Thus, eccentric strength of the knee musculature might play an important role for somersault height and run-up velocity in the vault. We investigated the correlation of eccentric peak torque of the knee flexors and extensors and vertical jumping height with backward somersault height and sprinting velocity in female junior artistic gymnasts. The results showed medium to strong, significant correlations between eccentric peak torque and backward somersault height as well as sprinting velocity. Vertical jumping height revealed significant correlations with somersault height and sprinting velocity. Eccentric strength seems to play an important role in joint stiffness regulation to utilize the elastic recoil of gymnastic floors and springboards. In the sprint approaching the vault, the same mechanism seems apparent and is in accordance with findings regarding the sprint in different sports.

THE INVESTIGATION OF APPROACH RUN IN TERMS OF AGE, GENDER, BIO-MOTOR AND TECHNICAL COMPONENTS ON VAULTING TABLE

Vault is one of the main apparatuses for both female and male gymnasts in artistic gymnastics (AG). The optimal vaulting technique depends on many variables, such as the approaching run. Gymnastics is one of the early specialization sports as it is necessary to start training at an early age. For this reason, the aim of the current study was to investigate the relationship among age, biomotor and technical components in relation to the approach run velocity and other variables in AG. Furthermore, similarities and differences between genders were researched. Twenty female and twelve male gymnasts took part in the study. Speed, agility, explosive power, run-up velocity were measured. Additionally, Reactive Strength Index (RSI) and Peak High Velocity distances (PHV_Distance) were calculated. Kinematic parameters during the handspring vault were calculated by a two-dimensional video analysis. A statistical comparison between genders was performed by the Mann Whitney U test. The relationships between parameters were given by Spearman correlation coefficients (r). Anaerobic power, 0-20 m speed, 20 m speed velocity, and the hand contact time were significantly different between genders (p&lt;0.05). The approach run significantly correlated with the chronological age (r=0.66; p=0.002 for female and r=0.96; p&lt;0.001 for male gymnasts), PHV_Distance (r=0.69; p=0.001 for female and r=0.97; p&lt;0.001 for male gymnasts) and the biological age (r=0.69; p=0.001 for female and r=0.97; p&lt;0.001 for male gymnasts). As the approach run velocity increases, vaulting performance is affected positively. While speed tests significantly correlated with the approach run in male gymnasts, there was no correleation for females. In addition, trainers should keep in mind that the relationship between bio-motor development and biological age of gymnasts is important in training programs.

Is gait-based visual regulation identical to gaze-based visual regulation in inexperienced athletes' long jump run-ups?

In long jumping, athletes need to hit a take-off board with both high precision and high run-up velocity to leap as far as possible. It is commonly agreed that visual regulation plays a crucial role in long jumping. To identify visual regulation, researchers have typically relied on analyses of variability in step parameters (i.e., "gait-based visual regulation"). The aim of the current study was to examine whether gait-based visual regulation coincides with measures of actual gaze control, referred to as "gaze-based visual regulation". Therefore, 15 participants performed long jumps and run-throughs while wearing a mobile eye-tracker. To compare gait-based with gaze-based visual regulation, a digital camera recorded all trials for subsequent frame-by-frame analyses of step parameters. Results revealed that gait-based visual regulation coincided with the step of the longest gaze (i.e., dwell time) on the take-off board but not with the step of initial gaze on take-off board. This finding supports the notion of visuomotor control of motor variability by means of longer gazing periods at the take-off board. In addition, our results provide initial insights to coaches and athletes on the particular requirements of visual regulation and the relationship between gait and gaze in the long jump approach.

Runup on a vertical column in strong water wave events

Runup on a slender cylindrical column exposed to long, steep waves, at finite and great depth is quantified by high speed camera technique in wave channel. Ratio between water depth (h) and cylinder diameter (D) is h/D=10,4.16,2.5. Breaking and non-breaking wave events are made by focusing technique. The trough-to-trough period (TTT), crest height (η0.m), frequency (ω=2π/TTT) and reference speed (g/ω) of each wave event are defined (g denotes acceleration of gravity). Wavenumber (k) is obtained from the dispersion relation. Experimental runup maximum (Rum) is presented in terms of variable Z=[2ω2(Rum−η0,m)/g]1/2. Measurements at finite water depth collapse along a linear relationship kη0,m=a+bZ where coefficients are obtained from the experiments. Results from other studies including large scale measurements fit to this curve, for h/D<5, kh<2 and kD<0.52. Results at great water depth with h/D=10 show, beyond a threshold wave slope, a similar relationship. Growth factor (1/b) is then much stronger. Gradual transition between results at finite depth and great water depth occurs for 5<h/D<10 and kh>2.5. Measured runup velocity along the column is up to 1.8 times the reference speed at great depth (h/D=10) and up to 1.2 times the reference speed at finite depth. Wave slope kη0,m is up to 0.56.

THE REGULATORY INFLUENCE OF THE VISUAL SYSTEM: AN EXPLORATORY STUDY IN GYMNASTICS VAULTING

Approach runs in order to maximize approach velocity are an inherent component in many sports. The goal of the study was to investigate the regulation of a complex motor task in gymnastics vaulting and the impact of the visual system within these processes. It was hypothesized that a visual perception-based strategy incorporating time-to-contact information derived from the variable tau is used to optimize the run-up in particular. Kinematic parameters of 10 gymnasts performing handsprings were examined. The analysis revealed that, on average, onset of visual control took place three steps prior to the hurdle. Linear regression showed that tau margin is dependent on the velocity of the approach run. The study supports the idea of a regulation of the run-up that is based on a visual strategy in which the influence of the vaulting table is crucial. The gymnasts were able to adapt the step length and duration respective to the movement velocity in order to facilitate an optimal transition of the run-up towards the take-off board and subsequent the vaulting table. In the process the influence of run-up velocity relating to the value of tau at the onset of visual control is of utmost importance.

The Effects of an Eight over Cricket Bowling Spell upon Pace Bowling Biomechanics and Performance within Different Delivery Lengths.

Pace bowlers must often perform extended bowling spells with maximal ball release speed (BRS) while targeting different delivery lengths when playing a multi-day match. This study investigated the effect of an eight over spell upon pace bowling biomechanics and performance at different delivery lengths. Nine male bowlers (age = 18.8 ± 1.7 years) completed an eight over spell, while targeting different lengths (short: 7–10 m, good: 4–7 m, full: 0–4 m from the batter’s stumps, respectively) in a randomized order. Trunk, knee and shoulder kinematics and ground reaction forces at front foot contact (FFC), as well as run-up velocity and BRS were measured. Paired sample t-tests (p ≤ 0.01), Hedges’ g effect sizes, and statistical parametrical mapping were used to assess differences between mean variables from the first and last three overs. No significant differences (p = 0.05–0.98) were found in any discrete or continuous variables, with the magnitude of difference being trivial-to-medium (g = 0.00–0.73) across all variables. Results suggest pace bowlers sustain BRS through a single eight over spell while tolerating the repeatedly high whole-body biomechanical loads as suggested by maintaining the kinematics or technique at the assessed joints during FFC. Practically, the findings are advantageous for bowling performance and support current bowling load monitoring practices.

DIFFERENCES IN VAULT RUN-UP VELOCITY IN ELITE GYMNASTS

The aim of this study was to compare differences in run-up velocity between Handsprings, Tsukahara and Yurchenko entry on vault. A sample consisted of 48 jumps performed on vault, 19 Handsprings, 17 Tsukahara and 12 Yurchenko entry on vault. Data were collected on a World Cup competition held in Osijek, 2017. Run-up velocity was measured by speed radar gun (Stalker ATS, S PRO II). Descriptive statistic was calculated for all variables and differences in run-up velocity were determined by one-way ANOVA and Bonferroni post-hoc test at the level of statistical significance at p&lt;.05. Average run-up velocity at Handspring entry was 8,06 m/s, Tsukahara, 8,06 m/s and Yurchenko entry on vault table was 7,66 m/s. ANOVA showed that exist statistical significant differences in run-up velocity between handspring and Yurchenko and between Tsukahara and Yurchenko entry. The results of this study indicated that different entry on vault table has different run-up velocity, which will help coaches and scientists to improve the vault technique.

FASTEST BOWLING DELIVERY IS ASSOCIATED WITH SELECTED KINEMATIC FACTORS IN JUNIOR PACE BOWLERS

The purpose of this study was to determine whether there are significant relation exists between ball release velocity and kinematics factors when bowls fastest delivery by U-19 pace bowlers. 10 male injury free junior pace bowlers (18.1±0.94 years) were enrolled from Ghazipur, Uttar Pradesh and filmed in an outdoor turf pitch (20.12 mtrs.) having sufficient area for run-up by four HD video cameras of 50 Hz and 60 fps frame rate were positioned at sagittal and frontal plane at a distance of 11 mtrs. For the digitization of data Kenovea – 8.24 was used. The Pearson Product Moment Method was calculated through IBM-SPSS 20. The result of the study shows that fastest ball release velocity has a positive significant association (0.638); inverse significant association (-0.747) and (-0.666,) among the shoulder angle at ball release, run-up velocity and trunk lateral flexion (TLF) respectively. In conclusion, kinematic factors like shoulder angle, run-up velocity and trunk lateral flexion are important issues to generate ball speed in junior pace bowlers. Article visualizations:

An analytical model of final average droplet size prediction of wave spray cloud

This study introduces an analytical model to predict the final average droplet size within a spray cloud that is formed due to wave interactions with marine objects. The process of spray cloud formation from wave impact involves several complicated processes, and each of these phenomena should be taken into account when considering an analytical approach. Following this process-based approach, the model first considers the wave characteristics and relates wave properties to the maximum impact pressure also considering the effect of air entrapment occurrence. Secondly, the maximum impact pressure is correlated empirically to the maximum wave run-up velocity. Finally, wave run-up velocity is linked with water sheet breakup models, which leads to the prediction of the final average diameter of ligaments and droplets. The prediction model is compared with experimental measurements from experiments conducted in a tow tank to form a spray cloud due to wave impact with two lab-scale models. Several measuring techniques such as image processing, bubble image velocimetry (BIV), and digital particle image velocimetry (DPIV) methods were implemented to measure the physical quantity of each phenomenon during the event of wave interaction. The effects of initial wave characteristics, the geometrical parameters of the impact condition and water sheet thickness at the moment of impact, on the final average droplet diameter were investigated. A sensitivity analysis of most of the principal parameters was performed to show the high veracity of the prediction model.

Estimation of jumping distance using run-up velocity for male long jumpers

Передумови та мета дослідження. Метою даного дослідження є дослідження взаємозв'язку між швидкістю розгону і довжиною стрибка і створення моделі оцінки стрибка, яку тренери можуть використовувати практично для спортсменів з великим рівнем працездатності. У стрибку в довжину близько 90% відстані - це дальність польоту спортсмена, а горизонтальна швидкість має найбільший вплив на відстань польоту між біомеханічними факторами і вона дуже важлива в таких стрибках. Тому, зокрема, швидкість спортсмена в останніх десяти метрах розбігу вважається найважливішою детермінантою цієї дії. Матеріал і методи: дані дослідження складалися з 328 дійсних стрибків 73 турецьких чоловіків-стрибунів, яким було 18,7 (+- 2,8) року. В результаті статистики кореляції, отриманої в цьому дослідженні, була побудована лінійна регресійна модель між останньою швидкістю в десять метрів і швидкістю стрибка, яка, як спостерігалося, мала найвищу кореляцію. Результати: Було відзначено, що швидкість розгону в останні десять метрів пояснює 76% дистанції стрибків. На основі оціночного рівняння можна стверджувати, що збільшення швидкості розгону для чоловіків-стрибунів на 0,1 м / с збільшить їх довжину стрибка на 10,7 см. Висновки. Було відзначено, що особливо швидкість в останніх 10 метрах розгону була одним з найбільш значущих предикторів успіху і модель оцінки, встановлена з використанням значення швидкості розгону, мала найсильніші відносини для отримання високоточних оцінок як для низьких, так і для високих значень.

An Experimental Study of the Run-Up Process of Breaking Bores Generated by Dam-Break Under Dry- and Wet-Bed Conditions

In this study, a series of dam-break laboratory experiments were carried out to investigate the run-up process of breaking bores under dry- and wet-bed conditions. Detailed measurements were conducted to reveal differences in the run-up hydrodynamic characteristics under these two conditions, e.g. the bore front profile, the maximum run-up height and duration, and the instantaneous bore front velocity. Two successive bores were observed under the wet-bed run-up process, while multiple bores (three bores in general) were generated during the dry-bed run-up process due to the significant bottom friction effect. A linear relationship with the uniform gradient is found between the maximum run-up height and the initial water head for both dry- and wet-bed conditions, indicating that difference in the maximum run-up height between the dry- and specified wet-bed cases or among various wet-bed cases is not sensitive to the initial water head. Under the same initial water head, although the dry-bed run-up process takes a longer duration than that of wet-bed cases, the maximum run-up height is smallest for the dry-bed case and gradually increases with the increase of the initial downstream water depth for wet-bed cases. Under the wet-bed conditions, temporal variation of the bore front run-up velocity can be classified into two stages, i.e. the acceleration stage induced by the relatively large incident bore front water depth (large onshore hydrostatic pressure gradient) and the deceleration stage governed by the offshore-directed gravity force and bottom friction. Nevertheless, due to the small incident bore front water depth, run-up process under the dry-bed conditions does not show the acceleration stage.

Three-Dimensional Numerical and Experimental Simulation of Wave Run-Up Due to Wave Impact With a Vertical Surface

This paper describes a numerical simulation of the interaction of a single nonlinear wave with a solid vertical surface in three dimensions. A coupled volume of fluid (VOF) and level set method (LSM) is used to simulate the wave-body interaction. A Cartesian-grid method is used to model immersed solid boundaries with constant grid spacing for simplicity and lower storage requirements. Mesh refinement is implemented near the wall boundaries due to the complex behavior of the free surface around the body. The behavior of the wave impact, the water sheet, and the high-speed jet arising from the wave impact are all captured with these methods. The numerical scheme is implemented using parallel computing due to the high central processing unit and memory requirements of this simulation. The maximum wave run-up velocity, instant wave run-up velocity in front of the vertical surface, the sheet break-up length, and the maximum impact pressure are computed for several input wave characteristics. Results are compared with a laboratory experiment that was carried out in a tow tank in which several generated waves were impacted with a fixed flat-shaped plate model. The numerical and experimental data on sheet breakup length are further compared with an analytical linear stability model for a viscous liquid sheet, and good agreement is achieved. The comparison between the numerical model and the experimental measurements of pressure, the wave run-up velocity, and the break-up length in front of the plate model shows good agreement.

Measurement of spray-cloud characteristics with bubble image velocimetry for braking wave impact

The process of spray-cloud production and flow kinematics arising from breaking wave impact on a fixed flat-shaped plate and a bow-shaped plate models were investigated based on the image velocimetry method. During wave impact and water sheet formation on a flat surface, an enormous amount of aerated flow is created in front of the surface. This process produces a significant number of bubbles in the resulting flow. The Bubble Image Velocimetry (BIV) was used to measure the wave run-up velocity. The BIV method uses these bubbles as a tracer and measures bubble velocity by correlating the texture in the bubble images. A high-speed camera was employed to record images for calculating fluid velocity. Instead of using a laser light sheet, a diffused LED backlight illuminated the bubble images. Two perpendicular plane views were used to capture the footages: a side and a front view. The wave run-up velocity measurements at the moment of impact are compared with the results of several published experimental results. Aside from the BIV method, spray characteristics were examined based on the Digital Particle Image Velocimetry (DPIV) method. This method was used for the area that the concentration of bubbles is low or no bubbles are present. Measurements of droplet size, and velocity, as well as wave run-up velocity, were major concerns in this study. Results of velocimetry from both views were compared, and a satisfactory agreement was achieved among >90% of the data. The highly transient process of spray formation from the liquid sheet breakup was discussed, and the drag coefficients and drag forces were calculated in two different stages of spray formation. Several pressure sensors were used to measure the impact pressure and three capacitive wave probes to measure the free surface profile. It was observed that higher impact pressure leads to the production of more dense and finer spray with a higher transition velocity. Moreover, it was illustrated that smaller size droplets have a higher velocity in compare with the medium and large size droplets, however, because of the effect of drag force these small size droplets cannot reach the maximum spray heights.

体操競技の跳馬における助走速度とその測定方法

体操競技の跳馬における助走速度とその測定方法