Ball Launch Research Articles

Mechanisms of speed-accuracy trade-off in tennis topspin forehand of college players

ABSTRACT This study aimed to elucidate the mechanisms underlying the speed-accuracy relationship in a tennis topspin single-handed forehand groundstroke. Groundstrokes at three different speeds by nine college players were captured, with the variability of the ball landing position evaluated as indices of accuracy. Variabilities of ball launch variables (speed, launch angle, spin, etc.) and conversion ratios from these variabilities to the variability of the ball landing position were quantified. These variabilities and their conversion ratios could be influenced by different efforts exerted to generate ball speeds and different ball trajectories required to hit a target at each speed, respectively. The speed-accuracy trade-off was observed only in the hitting direction. While the variability of the spin axis increased, it had minimal influence on the ball landing position. Conversely, the conversion ratio in the hitting direction of the velocity elevation angle significantly increased, while its variability remained unchanged. Consequently, the geometrical requirements of ball trajectories can be responsible for the speed-accuracy trade-off. Therefore, even skilled players capable of maintaining consistent ball launch variables regardless of the shot speed should deliberately choose a moderately slower ball speed to avoid an inevitable increase in the variability of the ball landing position due to geometrical requirements.

A Mobile App Driven Smart Ball Launch System for Solo Sports Training

Abstract: In today's world, athletes face intense competition in a variety of sports, but there are few opportunities for them to practice or evaluate their performance on their own, making it difficult for them to grow. Thus, a system is proposed in this paper that allows players to conveniently practice alone without requiring human assistance and may also help them in analyzing their skills. The method mostly concentrates on tennis game. The automatic ball launches for practice is the main aim of the system. With the assistance of a Node MCU that can interact over the internet, the system gives the user exact control over when to launch balls, what kind of ball to launch, and how to launch them remotely. Which is possible on mobile devices due to Blynk app interface. Typically, the system offers three different ball launch types: over spin, backspin, and rapid ball launch. It also allows for exact speed control of the motors used to make the ball launch.

Rapid Audiovisual Integration Guides Predictive Actions.

Natural movements, such as catching a ball or capturing prey, typically involve multiple senses. Yet, laboratory studies on human movements commonly focus solely on vision and ignore sound. Here, we ask how visual and auditory signals are integrated to guide interceptive movements. Human observers tracked the brief launch of a simulated baseball, randomly paired with batting sounds of varying intensities, and made a quick pointing movement at the ball. Movement end points revealed systematic overestimation of target speed when the ball launch was paired with a loud versus a quiet sound, although sound was never informative. This effect was modulated by the availability of visual information; sounds biased interception when the visual presentation duration of the ball was short. Amplitude of the first catch-up saccade, occurring ∼125 ms after target launch, revealed early integration of audiovisual information for trajectory estimation. This sound-induced bias was reversed during later predictive saccades when more visual information was available. Our findings suggest that auditory and visual signals are integrated to guide interception and that this integration process must occur early at a neural site that receives auditory and visual signals within an ultrashort time span.

DIFFERENCES IN KINEMATIC PARAMETERS BETWEEN FIRST AND SECOND SERVES IN TENNIS BY ELITE PLAYERS OF THE GERMAN LEAGUE

The primary goal of this research was to determine the differences in kinematic parameters between the first and second serves in tennis among the elite players of the German league. The sample of respondents in this research consisted of 30 elite male senior players of the German League who have "Leistungklasse" from 1 to 7. The kinematic parameters that were analyzed are: Height of ball impact (KPVUL), Racket speed (KPBRE), Ball speed (KPBLO), The angle at the elbow joint of the arm that hits the ball (KPULZ), Oscillation of the vertical projection of the center of gravity of the body (KPOVP), Jump height (KPVSK), Ball launch height (KPVIL), The point of contact between the ball and the racket "sweetspot" (KPMLR), Ball rotation "Top spin" (KPRLO). The video recording required for kinematic analysis was acquired with two Casio EX-F1 digital cameras at a frequency of 200 images per second. The camera was placed at an angle of 900 in relation to the recording plane, and they were at a distance of 10 m. Space calibration was performed with the help of a calibration frame (200 x 200 cm). We have installed Zepp Tennis Smart Sensor 2.0 in the handle of the Wilson Pro Staff RF97 Autograph racket, using the Zepp Tennis application software. "Kinovea" software was used for service analysis and obtaining kinematic parameters from video recordings. By analyzing the results of the T-test for independent samples, it can be seen that there are statistically significant differences in five of the nine analyzed kinematic parameters : KPBRE – kinematic parameter of racket speed (Sig.=.000), KPBLO – kinematic parameter of ball speed (Sig.=.000), KPULZ – kinematic parameter angle in the elbow joint (Sig.=.000), KPMLR – kinematic parameter point of contact between the ball and the racket (Sig.=.000), as well as a variable KPRLO – kinematic parameter of ball rotation (Sig.=.000). Larger numeric values in variables: KPVUL – kinematic parameter ball impact height, KPOVP – kinematic parameter of oscillation of the vertical projection of the center of gravity of the body, KPVSK – kinematic parameter jump height and KPVIL – kinematic parameter ball impact height, show a difference but it is not enough to be statistically different. Key words: tennis, kinematic analysis, racket speed, Zepp sensor

A comparative study in the vertical work done and the ball launch angle between the Float and crushing services of jumping in volleyball

The aim of the research is to find out - Recognizing the vertical work done and the angle of launching the ball for the skills of the smash and Float serve from jumping in volleyball. - Recognizing the differences in the vertical work done and the ball launch angle for the skills of the smash and Float serve from jumping in volleyball. The researchers hypothesized: - There are statistically significant differences in the vertical work done and the ball shooting angle between the skills of the smash and Float serve from jumping in volleyball. The researchers used the (descriptive) approach for its relevance to the nature of the research, and the research sample consisted of (6) players representing the Mosul University team for the year 2021 in volleyball, and the questionnaire, measurement, scientific observation, test and evaluation were used as means of data collection, where the research variables were determined through the analysis of similar studies and special literature With my smashing and Float serve skills from volleyball jump. Mass and length were measured, players were tested with three serves of each type (crushing and wavy), and the best serve of each type was evaluated for kinetic analysis. The scientific observation was carried out using a video camera placed next to the player with a distance of (4.35) meters and a lens height of (1.45 meters) and a scale drawing of one meter in length was used, images in the horizontal and vertical positions, to calculate the coefficient of change from the image to the truth to obtain the kinematic variables. The data was statistically processed using the SPSS program to obtain (arithmetic mean, standard deviation and t-test for related samples) and the equations that are related to the biomechanical variables. The researchers concluded: - The value of the completed vertical work was of a higher value when performing the skill of crushing serve because of the higher value of the vertical distance traveled to the center of mass of the body. - The value of the ball shooting angle was a higher value when performing the skill of Float serve. Through the conclusions, the researchers recommended: - The necessity of emphasizing on jumping high during the performance of the transmission skill to obtain the maximum height of the center of mass of the body and thus obtaining the appropriate amount of kinetic thrust. - Emphasis on training the rapid strength of the lower extremities for volleyball players because of its importance in achieving a higher jump and thus the height of the center of gravity of the body mass and achieving greater vertical work. - Paying attention during training to the Float serve from the jump, provided that the ball is not thrown at a great height and that the height is appropriate, which provides a good flight angle.

Development of a Golf Putting Training System for Quantitative and Intuitive Golf Ball Launch Information Instruction

Development of a Golf Putting Training System for Quantitative and Intuitive Golf Ball Launch Information Instruction

The Contribution of Ball Launching and Ring Entrance Angle Variables in 3 points Jump Shot in Basketball

The research aimed at identifying the values of ball launch and ring entrance angle and relations among them as well as identifying the contribution of ball launch and angle variables in 3 point jump in basketball. The researchers hypothesized statistical relation between ball launch and entrance angle. They used the descriptive method on (10) basketball players best known for their 3 point jump shot. Each player is given (10) attempts and only attempts with a larger entrance angle in recorded. The results showed that the height of ball launch players an integral role in decreasing entrance angle as well as ball launch angle did not correlate with the entrance angle. Finally, ball launch variables have no effect or contribution on ball entrance angle.

Comparing power hitting kinematics between skilled male and female cricket batters

ABSTRACT Organismic, task, and environmental constraints are known to differ between skilled male and female cricket batters during power hitting tasks. Despite these influences, the techniques used in such tasks have only been investigated in male cricket batters. This study compared power hitting kinematics between 15 male and 15 female batters ranging from university to international standard. General linear models were used to assess the effect of gender on kinematic parameters describing technique, with height and body mass as covariates. Male batters generated greater maximum bat speeds, ball launch speeds, and ball carry distances than female batters on average. Male batters had greater pelvis-thorax separation in the transverse plane at the commencement of the downswing (β = 1.14; p = 0.030) and extended their lead elbows more during the downswing (β = 1.28; p = 0.008) compared to female batters. The hypothesised effect of gender on the magnitude of wrist uncocking during the downswing was not observed (β = −0.14; p = 0.819). The causes of these differences are likely to be multi-factorial, involving aspects relating to the individual players, their history of training experiences and coaching practices, and the task of power hitting in male or female cricket.

Predicting golf ball launch characteristics using iron clubhead presentation variables and the influence of mishits

In golf, it is well understood that the interaction between the clubhead and ball determines the initial ball launch conditions. Specific knowledge regarding these relationships for iron clubs, particularly when clubhead and turf interactions are considered, would be both novel and of benefit to practitioners. Linear regression analysis was used to determine relationships between selected clubhead presentation and shot outcome variables for a sample of 1127 ‘5-iron’ shots hit from natural turf by 96 golfers. As expected, clubhead speed was the most significant predictor of ball speed, with obliquity of impact and eccentricity of the impact location making smaller, yet statistically significant contributions. Marginally ‘fat’ strikes, whereby the leading edge of the clubhead was only slightly beneath the ground at impact, appeared to have a lesser effect than expected in terms of ball speed. Effective loft was found to be the strongest predictor of vertical launch angle, whilst clubhead speed and spin loft had the greatest influence in the model for predicting total spin; inclusion of ‘thin’ strikes (i.e. those struck with the leading edge) appeared to create a non-linear element to these models and consequently overestimated the influence of vertical impact location in both cases. These findings suggest that determination of impact location, particularly for instances whereby ball contact is not wholly on the club face, is critical in research concerning irons. Overall, this study makes an original contribution to the understanding of 5-iron shot outcomes based on clubhead presentation characteristics.

The influence of 5-iron clubhead mass distribution on clubhead presentation and initial ball launch conditions – Part II: Player tests

Iron clubheads can be classified as blades or perimeter-weighted, depending on the distribution of their mass. Despite the widely held views that perimeter-weighting can offer performance benefits for lesser skilled players, a direct comparison with players using these two clubhead types has not been thoroughly investigated. The aims of the study were to determine differences in clubhead presentation and ball launch between a blade 5-iron and a cavity-back 5-iron in a mixed cohort of golfers and examine trends in central tendency and variability in relation to skill for males using the blade club. Nine clubhead presentation variables and six ball launch variables were measured for 96 participants hitting shots from natural turf with each of the clubs. Group means for club effect were analysed statistically using an independent samples approach, whilst a rank-based nonparametric test was used to determine significant trends between handicap categories and ball launch conditions for the male cohort. The cavity-back displayed higher effective loft, lower effective lie and a tendency to have ball strikes closer to the centre. Higher values were also noted for the cavity-back for vertical launch angle and total spin. As expected, higher handicap male golfers showed lesser consistency and displayed slower ball speeds and lower efficiency than the more skilled players. Together these results concur with the findings in Part I in support of the theory of ‘forgiveness’ associated with cavity-back clubs, whilst also highlighting the over-riding importance of skill level on performance.

The influence of 5-iron clubhead mass distribution on clubhead presentation and initial ball launch conditions: Part I: Golf robot tests

It is well accepted that iron clubhead properties affect shot outcomes in golf. However, the mechanisms that contribute to this relationship have not received recent scientific study. The purpose of this study was to determine how the different clubhead mass distributions in a blade 5-iron and a cavity-back 5-iron affect clubhead presentation and ball launch conditions. Nine clubhead presentation variables and four ball launch variables were measured for ten discrete impact locations and five face angles during swings using a golf robot. Group means were analysed statistically using an independent samples approach to identify differences and linear regression was used to indicate relationships between key launch variables. The cavity-back showed higher effective clubhead loft with greater total ball spin than the blade, despite having matched static lofts, whilst also providing more consistent launch outcomes across a range of impact locations. Evidence of the phenomenon known as the ‘gear effect’ was found for the cavity-back, but not the blade, suggesting that the threshold at which the clubhead’s centre of gravity (CG) is deep enough to detect the gear effect lies between the CGs of the two 5-iron types. These novel robot test findings lend support to the perceived performance benefits of perimeter-weighted irons; whether these effects translate to human golfer swings is reported in Part II of this paper.

The effect of using EMS electrical stimulation on some kinematic variables of the floater serve in volleyball

The importance of this study lies in knowing the development of the basic muscles in the performance of the arm by using electrical stimulation and its effect on technical performance, and to infer it through biochemical variables, which are reflected in realistic training and what is the extent of its value and its impact on the achievment of volleyball females players from the category of advancers. The study aimed to know : 
 -values of some biomechanical variables for the skill of the floater serve in the women's volleyball . 
 - the extent and effectiveness of the effect of using an EMS device on the arm muscles , its development and its reflection on the performance movement of the serve through the kinematic variables and the differences between the pre and post tests. 
 The descriptive approach was used by using the pre and post kinematic analysis. The research sample consisted of females players of the Qaraqosh Sports Club, who were 6 from the category of advancers. The researchers used the EMS device for the arm leading to the serve after imaging and analysis in the pre-test to extract the variables (shoulder angle at the moment of hitting the ball , maximum height of the ball at the moment of hitting the ball , ball launch velocity , ball launch angle, angular distance , time of movement, angular velocity) After completing the electrical stimulation program and sessions, over a period of five weeks, the same variables were analyzed in a post-test. 
 The most important conclusions of the study were - that the use of electrical stimulation EMS helped in the development of the ball’s launch velocity - there were statistical differences in the arithmetic averages in the variables of the angular velocity and the angular distance between the two pre and post tests as a result of the effect of electrical stimulation, which achieved even partially the goal of the research according to the kinematic view

Relationships between technique and bat speed, post-impact ball speed, and carry distance during a range hitting task in cricket

The ability of a batsman to clear the boundary is a major contributor to success in modern cricket. The aim of this study was to identify technique parameters characterising those batsmen able to generate greater bat speeds, ball launch speeds, and carry distances during a range hitting task in cricket. Kinematic data were collected for 20 batsmen ranging from international to club standard, and a series of ball launch, bat-ball impact, and technique parameters were calculated for each trial. A stepwise multiple linear regression analysis found impact location on the bat face in the medio-lateral and longitudinal directions and bat speed at impact to explain 68% of the observed variation in instantaneous post-impact ball speed. A further regression analysis found the X-factor (separation between the pelvis and thorax segments in the transverse plane) at the commencement of the downswing, lead elbow extension, and wrist uncocking during the downswing to explain 78% of the observed variation in maximum bat speed during the downswing. These findings indicate that players and coaches should focus on generating central impacts with the highest possible bat speed. Training and conditioning programmes should be developed to improve the important kinematic parameters shown to generate greater bat speeds, particularly focussing on increased pelvis to upper thorax separation in the transverse plane.

임팩트 시 골프 클럽 패스가 볼의 초기 출발 방향에 미치는 영향

임팩트 시 골프 클럽 패스가 볼의 초기 출발 방향에 미치는 영향

Optical and Acoustic Sensor-Based 3D Ball Motion Estimation for Ball Sport Simulators †

Estimation of the motion of ball-shaped objects is essential for the operation of ball sport simulators. In this paper, we propose an estimation system for 3D ball motion, including speed and angle of projection, by using acoustic vector and infrared (IR) scanning sensors. Our system is comprised of three steps to estimate a ball motion: sound-based ball firing detection, sound source localization, and IR scanning for motion analysis. First, an impulsive sound classification based on the mel-frequency cepstrum and feed-forward neural network is introduced to detect the ball launch sound. An impulsive sound source localization using a 2D microelectromechanical system (MEMS) microphones and delay-and-sum beamforming is presented to estimate the firing position. The time and position of a ball in 3D space is determined from a high-speed infrared scanning method. Our experimental results demonstrate that the estimation of ball motion based on sound allows a wider activity area than similar camera-based methods. Thus, it can be practically applied to various simulations in sports such as soccer and baseball.

Effects of a golf swing intervention on senior golfers’ ball striking and motivation to play golf

Several golf swing movements have been correlated with the production of club speed in skilled golfers. However, less skilled golfers, such as senior golfers, may not be capable of many of those movements. One golf swing—Minimalist Golf Swing—reduces the downswing range of motion through which a golfer’s body must move to reach the impact positions seen in skilled golfers. The purpose of this study was to assess whether the MGS could improve senior golfers’ ball flight and consistency, and increase their motivation to play golf. Twenty-two seniors (16 males, 6 females), aged 54–81, participated in an 11-session study comprising pretest, intervention, and posttest sessions. During the test sessions, participants hit 20 shots with each of their own 6-iron and driver clubs. Ball movement immediately after impact was measured using a camera-based ball launch monitor. Participants’ motivation to play golf before and after the intervention was assessed using the Sports Motivation Scale II. A mixed effects model was used for the statistical analysis of this repeated measures study, in which participants served as their own controls. Statistically significant per-session results were an increase in the ball’s speed (6-iron and driver) and trajectory (6-iron), and a change in direction (both clubs) from left to slightly right (for right handed golfers). Consistency of ball flight, total motivation and intrinsic motivation increased slightly post-intervention, while amotivation decreased, none significantly. Therefore, some senior golfers can improve ball flight, consistency, and motivation to play golf after six MGS training sessions.

Assessing rugby place kick performance from initial ball flight kinematics: development, validation and application of a new measure

The appropriate determination of performance outcome is critical when appraising a performer’s technique. Previous studies of rugby place kicking technique have typically assessed performance based on ball velocity, but this is not the sole requirement. Therefore, a mathematical model of rugby place kick ball flight was developed to yield a single measure more representative of true performance. The model, which requires only initial ball flight kinematics, was calibrated and validated using empirical place kick data, and found to predict ball position with a mean error of 4.0% after 22 m of ball flight. The model was then applied to the performances of 33 place kickers. The predicted maximum distance, a single performance measure which accounted for initial ball velocity magnitude and direction, and spin, was determined using the model and was compared against ball velocity magnitude. A moderate association in the rank-order of the kicks between these two measures (ρ = 0.52) revealed that the relative success of the kicks would be assessed differently with each measure. The developed model provides a representative measure of place kick performance that is understandable for coaches, and can be used to predict changes in performance outcome under different ball launch or environmental conditions.

The effects of vertically oriented resistance training on golf drive performance in collegiate golfers

The purpose of this study was to examine the effects of vertically oriented resistance training on golf driving performance. Ten Division-I collegiate golfers completed two resistance training sessions per week for 10 weeks during the fall tournament season. Pre- and post-training assessments of strength-power and golf performance were compared. To assess strength-power, jump height, peak force, and peak power were measured from static and countermovement vertical jumps; peak force and rate of force development from 0 to 250 ms were measured from an isometric mid-thigh pull. Golf performance was assessed in terms of ball launch speed, spin rate, carry yardage, and total yardage, averaged from five shots using a driver. Following training, all measures of strength-power improved, with countermovement jump peak power improving significantly ( p < 0.00625). The golf performance assessment indicated significant increases ( p < 0.0125) in ball speed, carry yardage, and total yardage. These results suggest that vertically oriented resistance training can improve golf driving performance.

소형구의 속도증폭을 위한 사보 조립체의 실리콘고무 특성 연구

A mini ball launch system was developed for the study of dynamic fracture of ceramic materials. The principle of velocity multiplication system is similar to two stage gun. The plastic sabot assembly houses steel plunger and the void filled with silicone rubber. The sabot is stopped by the stopper block then the steel plunger inside the sabot compress the silicone rubber to high pressure. Then the compressive energy of the silicone rubber is transferred to the ball. More than ten times of initial speed was attained. In this study, most effective silicone rubber for the highest final speed was chosen out of three different varieties by launch tests.

Drive Performance for Able-Bodied and Disabled Golfers

Golf is a popular leisure and competitive activity for individuals with disabilities. The current golf handicap system does not take into account the possible challenges of playing golf with any form of physical disability. The aim of this study was to examine golf driving performance measures, comparing golfers with various types of physical disabilities to able-bodied golfers. Through drive shot ball launch analysis, this study compared amputees (single leg, below and above knee), deaf, visually impaired, polio, Les Autres and arthrogryposis golfers to able-bodied golfers with similar golf handicaps. Twenty-seven able-bodied (handicap category 3, 12.4 ± 7.0) and 15 disabled (handicap category 3, 18.2 ± 9.2) hit 10 drives each. Able-bodied golfers presented longer but less accurate drives (208.1 m carry, 4.6 m lateral deviation), and concomitant higher club head and ball velocity than disabled golfers (157.6 m carry, 6.0 m lateral deviation) [p<0.001]. The apparent difference in outcome performance cannot be fully accounted for by the small difference in golf handicap score, thus disabled golfers appear to be penalised/disadvantaged by the current golf handicap classification rules.