Ball Flight Research Articles

Tennis ball flight under strong wind

Tennis ball flight under strong wind

All in an engineer’s life

All in an engineer’s life

Gaze pursuit and arm control of adolescent males diagnosed with attention deficit hyperactivity disorder (ADHD) and normal controls: evidence of a dissociation in processing visual information of short and long duration

Three-dimensional kinematic analysis of line of gaze, arm and ball was used to describe the visual and motor behaviour of male adolescents diagnosed with attention deficit hyperactivity disorder (ADHD). The ADHD participants were tested when both on (ADHD-On) and off (ADHD-Off) their medication and compared to age-matched normal controls in a modified table tennis task that required tracking the ball and hitting to cued right and left targets. Long-duration information was provided by a pre-cue, in which the target was illuminated approximately 2 s before the serve, and short-duration information by an early-cue illuminated about 350 ms after the serve, leaving ~500 ms to select the target and perform the action. The ADHD groups differed significantly from the control group in both the pre-cue and early-cue conditions in being less accurate, in having a later onset and duration of pursuit tracking, and a higher frequency of gaze on and off the ball. The use of medication significantly reduced the gaze frequency of the ADHD participants, but surprisingly this did not lead to an increase in pursuit tracking, suggesting a barrier was reached beyond which ball flight information could not be processed. The control and ADHD groups did not differ in arm movement onset, duration and velocity in the short-duration early-cue condition; in the long-duration pre-cue condition, however, the ADHD group's movement time onset and arm velocity differed significantly from controls. The results show that the ADHD groups were able to process short-duration information without experiencing adverse effects on their motor behaviour; however, long-duration information contributed to irregular movement control.

An investigation of the effectiveness of Bolle's Competivision sport‐glasses on tennis performance

Background: Specifically, Bollé claims the Competivision lens will enhance the ability of a player to visually perceive a tennis ball and may subsequently improve athletic performance. This study examined the impact on tennis performance of wearing Bollé Competivision tennis sport‐glasses.Methods: Twenty subjects of three tennis skill levels were measured in relation to their hitting accuracy and movement initiation speed while hitting ground strokes projected from a sports action machine. Each participant completed 40 test trials under three conditions: wearing Competivision lenses, wearing clear lens glasses (used as a placebo to create an expectancy of improved performance) and not wearing glasses. Result: No significant differences were found between any treatment conditions or skill groups for movement initiation time. There was a significant difference in hitting accuracy between the skill levels, with the advanced and intermediate skill groups being more advanced than the novices, but this difference was independent of treatment condition. Additionally, there was no significant difference in hitting accuracy between the treatment conditions.Discussion: Possible causes of the results include the role of ball flight information for successful hitting performance and the transfer of colour contrast sensitivity to enhanced sports performance.

Cricket bowling deliveries and the discrimination ability of professional and amateur batters

Bowlers in cricket try to disguise their bowling action by movement pattern similarity. The batter’s task is, therefore, to solve rapidly perceptual discrimination problems. Previous research has suggested that batters can discriminate perceptual cues that provide depth or target information. However, at present, there is a lack of applied research evidence on further perceptual cue utilization, including bowling delivery identification. This ability is required when batting against wrist-spin bowlers who may use five different types of delivery. In the present study, we assessed this perceptual discrimination ability among three distinct standards of batters. In addition, the relative potency of body action and ball flight information was assessed by visual occlusion techniques. We found that more expert batters in general showed greater perceptual discrimination skills when faced with different ball types. However, this discrimination ability was linked specifically to delivery type and to previous experience. We also found that additional ball flight information provided no more advantage to this discrimination ability. This finding reinforces the importance of advanced cue information and the need to expose cricket batters to different bowling actions. Further study of the development of movement pattern recognition is recommended.

Imagery processes in evaluating duration of a ball flight.

That imagery processes may intervene in the representation of movement of usual objects through time was confirmed by showing that high scores on the 1986 Vividness of Movement Imagery Questionnaire predicted with greater accuracy than low scorers the duration of a largely masked ball flight.

Monocular and Binocular Vision in One-Hand Ball Catching: Interocular Integration

In 2 experiments, binocular and monocular vision were compared and interocular integration in 1-hand ball catching was examined. Participants (N = 10 in each experiment) were required to catch tennis balls projected over a distance of 15 m. Participants wore liquid-crystal visual occlusion goggles so that the duration and frequency of visual samples provided to their eyes over ball flight could be manipulated. An examination of catching performance indicated that binocular vision contributed to both the spatial and temporal aspects of the catching task. Experienced catchers are able to integrate information from the 2 eyes over intervals as long as 80-100 ms. When provided with only intermittent monocular samples of ball flight, catching performance deteriorated rapidly as the interval between consecutive samples was increased. Results are discussed both in terms of the sources of visual information useful for the interception of objects and the temporal differences for interocular integration between the perception of form and visual-motor control.

Prediction in Ball Catching by Children with and without a Developmental Coordination Disorder

This study aimed to determine how predicting ability in ball catching changes with age and to explore this among children with developmental coordination disorder (DCD) as judged by performance on the Movement Assessment Battery for Children (Henderson & Sugden, 1992) and by clinical evaluation. In Experiment 1, participants were 157 non-DCD children, age 5-12. In Experiment 2, 46 participants (age 5-7) from Experiment 1 were controls for 40 same-age children with a DCD. In Experiment 1, younger children (age 5-6) did not predict ball flight as well as older groups at short viewing times, and girls did not predict as well as boys. In Experiment 2, DCD children predicted more poorly at most viewing times compared to non-DCD peers. It was concluded that age and gender are crucial factors in predicting ball flight and that predicting ability is a fundamental problem in catching for younger, female, and DCD children.

Hip and shoulder rotations during the golf swing of sub-10 handicap players

The motion of the shoulders, arms and club during the golf swing has often been explained using the ‘double pendulum’ model. Despite subsequent explanations for the actions of the distal segments of the body, the coordination of more proximal segments during the swing is less well understood. To ascertain the pattern of centre of mass motion and hip and shoulder rotations that result in a high clubhead speed at impact, the swing used in driving from the tee of eight low-handicap golfers was videotaped and analysed using three-dimensional techniques. The shoulders rotated in excess of 90o during the backswing and, in 75% of the golfers, continued rotating away from the flag as the hips began turning back towards it. This sequential pattern of hip and shoulder rotation indicated that they conformed to the ‘summation of speed’ principle, which is hypothesized to result in a greater torque being applied to the club before impact. The speed of the drive was also benefited by the centre of mass shifting exclusively in the intended direction of ball flight during impact.

Catching With Both Hands: An Evaluation of Neural Cross-Talk and Coordinative Structure Models of Bimanual Coordination

Kelso, Southard, and Goodman (1979) and Marteniuk and MacKenzie (1980) have each proposed a different theoretical model for bimanual coordination. In the model of Kelso et al., a close temporal relationship between the hands in a bimanual task is predicted, even when each hand is required to move different distances. In Marteniuk and MacKenzie's model, separate motor commands are issued so that each limb will arrive simultaneously at the specified movement endpoint, leading to low temporal associations between limbs. In most previous work on bimanual coordination, manual aiming tasks with differing constraints have been used by subjects in individual studies. In this study, the usefulness of existing models for predicting performance in a real-world catching task in which the required movement pattern was constrained by ball flight characteristics was examined. Eleven university students caught tennis balls with both hands in the following 3 conditions: Condition 1. Ball projected to the right shoulder area (left hand moved a greater distance than the right); Condition 2. Ball projected to center of the chest area, (both hands moved same distance); and Condition 3. Ball projected to left shoulder area (right hand moved a greater distance). Kinematic data (time to peak velocity, movement initiation time) indicating significant cross-correlations between the left and right limbs in all 3 conditions concurred with the data of Kelso et al. (1979) on manual aiming. Timing appeared to be an essential variable coordinating bimanual interceptive actions. Although the limbs moved at different speeds when each was required to move different distances, times to peak velocity showed strong associations, suggesting the presence of a coordinative structure.

Visual factors in hitting and catching

To hit or catch an approaching ball, it is necessary to move a bat or hand to the right place at the right time. The performance of top sports players is remarkable: positional errors of less than 5 cm and temporal errors of less than 2 or 3 ms are reliably maintained. There are three schools of thought about how this is achieved. One holds that predictive visual information about where the ball will be at some future instance (when) is used to achieve the hit or catch. The second holds that the bat or hand is moved to the correct position by exploiting some relation between visual information and the required movement. The third focuses on the use of prior knowledge to supplement inadequate visual information. For a rigid spherical ball travelling at constant speed along or close to the line of sight, the retinal images contain both binocular and monocular correlates of the ball's instantaneous direction of motion in depth. Also, the retinal images contain both binocular and monocular information about time of arrival. Humans can unconfound and use this visual information, but they are unable to estimate the absolute distance of the ball or its approach speed other than crudely. In cricket, this visual inadequacy allows a slow bowler to cause the batsman to misjudge where the ball will hit the ground. Such a bowler uses a three-pronged strategy: first, to deliver the ball in such a way as to prevent the batsman from obtaining the necessary visual information until it is too late to react; secondly, to force the batsman to rely entirely on inadequate retinal image information; thirdly, to allow the batsman to learn a particular relationship between the early part of the ball's flight and the point where the ball hits the ground, and then to change the relationship with such skill that the batsman does not detect the change.

The effects of baseball experience on movement initiation in catching fly balls

Previous research has shown that skilled athletes are able to respond faster than novices to skill-specific information. The aim of this study was to ascertain whether expert outfielders are faster than non-experts in acting on information about the flight of a fly ball. It was hypothesized that expert outfielders are better attuned to this information; as a result, faster and more accurate responses were expected. This hypothesis was tested by having non-expert and expert outfielders judge, as quickly as possible, where a ball would land in the frontbehind dimension (perceptual condition) and, in another condition, to attempt to catch such balls (catching condition). The results of the perceptual condition do not support the hypothesis that expert outfielders are more sensitive to ball flight information than non-experts, but the results of the catching condition reveal that experts are more likely to initiate locomotion in the correct direction.

Real-Time Locus Indication System for a Flying Golf Ball

This paper describes a newly developed real-time locus indication system for a golf ball in flight. The system, named Shot View, detects the three-dimensional position of the ball according to triangulation principles using the motion angle of two cameras to track the ball, and indicates the locus on a course layout background. The system has been applied to long drive shots at a distant hole during several golf broadcasts and was well received by TV audiences. The principles of the Shot View system, the experiments conducted to ascertain its applicability to golf, the system configuration, the technology, and some examples of broadcasts using the system are presented.

Physical model, theoretical aspects and applications of the flight of a ball in the atmosphere. Part III: Theory in the case of vertical angular frequency and in the general spin‐case

AbstractIf a ball is viewed as a rigid body, its flight in the atmosphere can be described by six ordinary differential equations, which has been derived in the first part of this paper.In this following third part, some further theoretical aspects in the case of vertical angular frequency will be pointed out using an unknown transformation of the original independent variable, i.e. the time, as indicated in Part II.Last, but not least, the general case of angular frequency is to be treated. A rough qualitative discussion of the solutions is given as well as—if the equations are viewed as a three‐dimensional dynamical system—the unique stable equilibrium, which depends on the spin. This equilibrium turns out to be globally attractive, which can be proved by the construction of a suitable Ljapunov function. Then, the ball flight system can be transformed into a fourth‐order scalar differential equation.

Gender discrimination in biological motion displays based on dynamic cues

Studies of human locomotion have found that male and female walkers differ in terms of lateral body sway, with males tending to swing their shoulders from side to side more than their hips, and females tending to swing their hips more than their shoulders. Experiments reported here demonstrate that naive viewers can identify the gender of the figure in a biological motion display very reliably when the display contains gender-specific lateral body sway. Sensitivity to gender is high even for displays containing only a fraction of a step cycle. This dynamic cue dominates structural cues based on torso shape (`centre-of-moment9) when the cues are set in opposition. It is mediated by gender-specific differences in the velocity of shoulder and hip dots, not by positional differences in shoulder and hip dots during the step cycle.

Phasing and the Pickup of Optical Information in Cascade Juggling

Four experiments were conducted to examine the relationship between the phasing of hand movements and the pickup of optical information in cascade juggling. Three jugglers of intermediate skill juggled three balls while wearing liquid crystal (LC) glasses that opened and closed at preset intervals. The first experiment, in which the duration of the viewing window was gradually reduced to zero, revealed a preference for seeing the segment of the ball flight following the zenith in one subject; such a preference was hinted at in the other two subjects. The second experiment, in which the tachistoscopic rhythm of the glasses was perturbed, showed that, in the case of a stable phase lock, the phasing of the hand movements was adjusted to restore the visibility of the segment following the zenith when it was lost. The third experiment, however, revealed that, after practice, the jugglers did not become better attuned to the optical information contained in this segment. The fourth experiment, in which two jugg...

Optimization of clubhead loft and swing elevation angles for maximum distance of a golf drive

This paper presents a study on the optimization of loft and swing elevation angles on the impact between the clubhead of a driver and a golfball in order to maximize the distance of a drive. Computer programs were written to simulate the collision between the golfball and clubhead as well as the golfball in flight. A general, three-dimensional impact model using principles of momentum conservation on rigid bodies was used to simulate the impact between the golfball and clubhead to extract the spin and velocity vectors of the ball after impact. An aerodynamic model was then used to simulate ball flight in order to obtain the landing position of the ball. The results of the golfball landing positions generated by the computer simulations were compared to experimental data of golfball landing positions of shots hit by the golfing robot ‘Iron Byron’. The computer models were then used to calculate the optimal loft and swing elevation angles for a particular swing speed, clubhead mass, and golfball aerodynamic properties by making use of a nonlinear optimization routine. Also, the relationship between the maximizing distance for various driver loft angles and swing elevation angles is discussed.

Visual information pick-up in ball-catching

Ball-catching involves spatio-temporal information about the ball's flight path. There exist discrepancies among the results obtained by previous authors as to the role of binocular visual information. Two main motion detecting systems (MDS) have been described. In the one case (that of the image/retina system), the eyes remain motionless and the image of the mobile object moves across the retina. In the other (that of the eye/head system), the eyes and/or the head move so that the image of the moving object is maintained at the same place on the fovea. The subjects' performance levels generally improve discontinuously depending on the time required to pick up the relevant visual information (information pick-up time: IPT). Within this context, the following questions arose: (i) what role does binocular visual information play? (ii) what effects may the MDS have on the information in question? (iii) how efficient are the MDS at various IPT's? and (iv) which MDS is spontaneously used by subjects? The most noteworthy findings obtained were that: (i) binocular visual information is used to predict the place of arrival of the ball; (ii) binocular information is useful only when the subject is using the eye/head system; (iii) under highly constrained conditions (IPT 260 to 400 ms), tracking the ball with the eyes is not necessarily the most efficient strategy; and (iv) subjects spontaneously use the more efficient of the two MDS: the eye/head system is used only when it is liable to produce quantitatively and/or qualitatively better results.

Golf Instruction: Learning from the Flight of the Golf Ball

Abstract The flight pattern of the ball offers a storehouse of information which can greatly enhance the golf swing. Ball flight is a graphic portrayal of how the ball was struck. Becoming familiar with the factors that shape ball flight patterns should facilitate one's golfing prowess.

Anticipation in squash: Differences in advance cue utilization between expert and novice players

The time of occurrence and spatial location of the advance cues used to anticipate the direction and force of an opponent's stroke in squash were examined using a film task. This task, designed to stimulate the normal perceptual display of the defensive player, consisted of two discrete parts, each containing 160 individual stroke sequences (trials). In the first part of the film task, the display was occluded at different time intervals throughout the development of the opponent's stroke and the 16 expert and 20 novice subjects had to predict both the direction (down-wall or cross-court) and force (drive or drop shot) of the opponent's stroke. In the second part of the film task, visibility to selected advance cues was occluded by placing opaque mats on the film surface. Across all of the film task conditions experts were superior to novices in predicting the event outcome from the information available, highlighting the important contribution anticipatory skills make to expert performance in this sport. Analysis of lateral (direction) error showed that the most critical time periods for extracting information about stroke direction are the periods between 160-80 ms prior to racket-ball contact and the period of extended ball flight arising at least 80 ms after contact. Whereas both groups were attuned to this ball flight information, only the experts were capable of picking up information from the early part of the opponent's actions. This early information appeared to be provided by the opposing player's arm action. Similar time periods were found to be also important for the prediction of stroke depth, but in this case both experts and novices were similar in their cue dependence.