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Purpose: To study whether novices can use sonification to enhance golf putting performance and swing movements. Method: Forty participants first performed a series of 2 m and 4 m putts, where swing velocities associated with successful trials were used to calculate their mean velocity profile (MVP). Participants were then divided into four groups with different auditory conditions: static pink noise unrelated to movement, auditory guidance based on personalized MVP, and two sonification strategies that mapped the real-time error between observed and MVP swings to modulate either the stereo display or roughness of the auditory guidance signal. Participants then performed a series of 2 m and 4 m putts with the auditory condition designated to their group. Results: In general our results showed significant correlations between swing movement variability and putting performance for all sonification groups. More specifically, in comparison to the group exposed to static pink noise, participants who were presented auditory guidance significantly reduced the deviation from their average swing movement. In addition, participants exposed to error-based sonification with stereo display modulation significantly lowered their variability in timing swing movements. These results provide further evidence of the benefits of sonification for novices performing complex motor skill tasks. Conclusions: More importantly, our findings suggest participants were able to better use online error-based sonification rather than auditory guidance to reduce variability in the execution and timing of their movements. [ABSTRACT FROM AUTHOR]

Purpose: Golf coaches may recommend "blind" putting drills in which golfers close their eyes to improve their feel. Research on specificity of learning suggests, however, that adding or removing a source of sensory information after practicing under differing circumstances can cause performance decrements. Specificity of learning is also dependent upon specific task requirements. The purpose of this study was to examine whether golf putting, requiring body positioning and aiming an implement, would benefit from blind training. Method: Novice golfers (n = 24) in Vision Training (VT) & No-Vision Training (NVT) groups completed 108 trials of a 10-ft putt. After a 24-hr delay, both groups completed sighted- and blind-putting tests. Results: Acquisition results revealed Group × Block interactions in RE (p = .025) and y-VE (p = .032). Post hoc procedures revealed significant differences between the groups on Block 2 (p = .017), with the NVT group producing longer mean RE. During testing, RE and x-VE results revealed Group × Test interactions (p = .027 & .041), such that performance of the VT group suffered when transferred to blind putting, while performance of the NVT group did not differ when transferred. Conclusion: NVT did not confer any advantage for subsequent performance with vision. Moreover, results were not consistent with the specificity of learning hypothesis and suggest that putting does not rely on complete sensory integration to support subsequent performance. Presumably, task requirements related to body positioning provided adequate sensory cues for successful performance. [ABSTRACT FROM AUTHOR]

During putting in golf, the direction and velocity of the club head should be consistent across swings. In order to maintain consistency in swing timing, the cerebellum provides temporal information, motor timing, control of rhythm, and timing of movements. We utilized Interactive Metronome (IM), a brain training software program that combines the concepts of neurotechnology with the abilities of a computer, to improve an individual's rhythm and timing. We propose that IM would activate neural networks involved in decreasing variation in putt swing. Twenty professional female golfers (KLPGA) were randomly assigned to either an IM training group (n = 10, 35-40 min per session, twice a week for 6 weeks) or a control group (n = 10). The golf putting movements and brain activity were analyzed using Kinovea Software and resting state functional MRI, respectively. Consistency was measured as the standard deviation of mean swing speed (SSD) during three sections of the swing: backswing (AD-BS), backswing-impact (BS-IMP), and impact-finish (IMP-FIS). Our results show that the consistency of the IM group improved in the time between the back swing and impact in the 2 m putt and 5 m putt compared to the control group. Using functional MRI, after the training period, the IM group showed increased functional connectivity from the superior cerebellar vermis to the right medial frontal gyrus, left superior temporal gyrus, right middle occipital gyrus, right middle temporal gyrus, right cingulate gyrus, and right supramarginal gyrus (uncorrected p < 0.001, voxels > 40). These findings suggest that IM training in professional female golf players may improve consistency in putt timing. In addition, IM training may increase brain connectivity from the cerebellum to the frontal cortex, which plays an important role in motor control and timing. [ABSTRACT FROM AUTHOR]

Exploring relations between patterns of peak rotational speed of thorax, pelvis and arm, and patterns of EMG signals recorded from eight muscle regions of forearms and shoulders during the golf swing is the main objective of this article. The linear canonical correlation analysis, allowing studying relations between sets of variables, was the main technique applied. To get deeper insights, linear and nonlinear random forests-based prediction models relating a single output variable, e.g. a thorax peak rotational speed, with a set of input variables, e.g. an average intensity of EMG signals were used. The experimental investigations using data from 16 golfers revealed statistically significant relations between sets of input and output variables. A strong direct linear relation was observed between linear combinations of EMG averages and peak rotational speeds. The coefficient of determination values R 2 = 0.958 and R 2 = 0.943 obtained on unseen data by the random forest models designed to predict peak rotational speed of thorax and pelvis , indicate high modelling accuracy. However, predictions of peak rotational speed of arm were less accurate. This was expected, since peak rotational speed of arm played a minor role in the linear combination of peak speeds. The most important muscles to predict peak rotational speed of the body parts were identified. The investigations have shown that the canonical correlation analysis is a promising tool for studying relations between sets of biomechanical and EMG data. Better understanding of these relations will lead to guidelines concerning muscle engagement and coordination of thorax, pelvis and arms during a golf swing and will help golf coaches in providing substantiated advices. [ABSTRACT FROM AUTHOR]

Substantial experiential research into x-factor, and to a lesser extent crunch-factor has been undertaken with the aim of increasing clubhead speed. However, a direct comparison of the golf swing kinematics associated with each 'factor' has not, and possible differences when using a driver compared to an iron. Fifteen low handicap male golfers who displayed a modern swing had their golf swing kinematic data measured when hitting their own driver and five-iron, using a 10-camera motion analysis system operating at 250Hz. Clubhead speed was collected using a validated launch monitor. No between-club differences in x-factor and crunch-factor existed. Correlation analyses revealed within-club segment (trunk and lower trunk) interaction was different for the driver, compared to the five-iron, and that a greater number of kinematic variables associated with x-factor, compared to crunch-factor were shown to be correlated with faster clubhead speeds. This was further explained in the five-iron regression model, where a significant amount of variance in clubhead speed was associated with increased lower trunk x-factor stretch, and reduced trunk lateral bending. Given that greens in regulation was shown to be the strongest correlated variable with PGA Tour earnings (1990-2004), the findings suggests a link to player performance for approach shots. These findings support other empiric research into the importance of x-factor as well as anecdotal evidence on how crunch-factor can negatively affect clubhead speed. [ABSTRACT FROM AUTHOR]

At its core, like many other sports, golf is a game of integers. The minimization of the number of strokes played is generally what determines the winner, whether each of these are associated with the shortest of putts or the longest of drives. The outcomes of these shots are influenced by very slight changes, but hopefully in a deterministic sense. Understanding the mechanics of golf necessitates the development of models and this is coupled more often than not to the use of statistics. In essence, the individual aspects of the sport can be modelled adequately via fairly simplistic models, but the presence of a human at one end of the kinematic chain has a significant impact on the variability of the entire process. In this paper, we will review some of the ways that mathematics has been used to develop the understanding of the physical processes involved in the sport, including some of the analysis which is exploited within the Equipment Rules. We will also discuss some of the future challenges. [ABSTRACT FROM AUTHOR]

We examined the effects of attentional focus instructions on the learning of movement form and carry distance in low-skilled golfers. The X-factor describes the rotation of the shoulders relative to the pelvis, and its increase during the downswing (so-called X-factor stretch) is associated with the carry distance of the ball. X-factor stretch and carry distance have been shown to be associated with an early weight shift toward the front leg during the downswing. In our study, one group (internal focus, IF) was instructed to focus on shifting their weight to their left foot while hitting the ball, whereas another group (external focus, EF) was instructed to focus on pushing against the left side of the ground. A control (C) group was not given attentional focus instructions. Participants performed 100 practice trials. Learning was assessed after a 3-day interval in a retention test without focus instructions. The EF group demonstrated a greater carry distance, X-factor stretch, and higher maximum angular velocities of the pelvis, shoulder, and wrist than both the IF and C groups, which showed very similar performances. These findings demonstrate that both movement outcome and form can be enhanced in complex skill learning by providing the learner with an appropriate external focus instruction. Moreover, they show that a single external focus cue can be sufficient to elicit an effective whole-body coordination pattern. [ABSTRACT FROM AUTHOR]

Participants were 20 younger golfers (M age = 19.8 years, SD = 1.84 years) and 20 older golfers (M age = 63.0 years, SD = 2.55 years) who attempted 40- and 80-yard eight-iron shots requiring an adjustment of their force and timing. No age-related differences were found in the tempo or speed of the shot; however, there were differences in the rhythmic relationship between the clubhead force and the weight shift. Whereas younger golfers primarily exhibited a 3 versus 2 polyrhythmic pattern between the peak forces of the clubhead and weight shift, older golfers primarily exhibited a simpler 3 versus 3 rhythmic force pattern by adding a forward weight shift at the beginning of the shot. Additionally, older golfers exhibited less independence between the timing of the clubhead force and weight shift, which indicated greater use of a single integrated coordinative unit rather than 2 units. These findings are interpreted as compensations for age-related slowing and increased temporal variability that help to preserve tempo at a speed comparable to younger adults. [ABSTRACT FROM PUBLISHER]

Golf shafts are normally characterised using static or quasi-static tests, yet the golf swing itself is dynamic. The purpose of this research was to determine whether stiffness properties obtained from these tests can be used when modelling the dynamic behaviour of golf shafts made from carbon fibre reinforced polymer (CFRP). Three shafts, matched for all properties except shaft flex, were subjected to human swing testing by 12 skillful players whilst strains were recorded. Peak principal strains as well as strain rates increased as shaft flex decreased ( p < 0.001). CFRP flat panels with lay-ups similar to those contained in the shafts were constructed and tested statically and at strain rates between 10 and 4 s. Some level of strain-rate dependency was found for these panels, but only for strain rates exceeding those seen during a swing, which suggests that static material tests are appropriate for measuring the dynamic stiffness of golf shafts. [ABSTRACT FROM AUTHOR]

In this paper a four-ball-best-ball (4BBB) model for pairs of golf players is set up. The 4BBB match-play scoring system is seen to satisfy a basic requirement of fairness. It is shown that it is not strictly possible to rate individual players as 4BBB players. However, a (reasonably broad) class of individual players is identified such that it is possible to rate them individually as 4BBB players. The capacity of an individual to play birdies is seen to be a very important determinant in being a successful member of a 4BBB pair, but there are other minor factors as well. Consideration is given to equal and unequal 4BBB pairs. The transitive law is seen to apply for 4BBB pairs. Thus, if pair A is better than pair B, and pair B is better than pair C, then pair A must be better than pair C. Correspondingly, if pair A is equal to pair B, and pair B is equal to pair C, then pair A is equal to pair C. Consideration is given to some strategic issues in 4BBB match-play golf. For example, the conditions under which a player should take a greater risk and have a higher probability of obtaining a bogie in order to achieve a higher probability of scoring a birdie, are determined. Also, the conditions under which a player, noting that his partner is about to have a 'bad' hole and score only a par or a bogie, should 'play safe', are determined. Thirdly, players who can interact in certain ways are seen to have an advantage over those pairs that cannot do this. Finally, one pair's optimal strategy when they see that their opponents are about to score a par or a bogie, but not a birdie, is analyzed. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine trunk rotational patterns and weight transfer patterns that may differentiate swing skill level in golfers. Thirteen skilled golfers (mean handicap = 0.8 ± 2.6) and seventeen low skilled golfers (mean handicap = 30.8 ± 5.5) participated in this study. Kinematic and kinetic data were obtained through high-speed 3-D videography and force plates while the participant performed a full shot golf swing with a driver. Data at six temporal events during the swing were selected for the analysis. The results indicated that significant differences existed between the groups in the multiple events, as the skilled golfers showed the following motion patterns when compared to the low skilled golfers; 1) An earlier trunk horizontal rotation with a rapid weight transfer to the trail foot during the backswing; 2) An earlier pelvic horizontal rotation accompanied with an earlier weight transfer to the lead foot during the downswing motion; and 3) Less upper trunk horizontal rotation and more posterior pelvic rotation at the follow through. Collectively, these finding may be useful for instruction of golfers to improve their swing mechanics on a full shot golf swing. [ABSTRACT FROM AUTHOR]

This study investigates the effect of synchronized metronome training (SMT) on motor timing and how this training might affect golf shot accuracy. Twenty-six experienced male golfers participated (mean age 27 years; mean golf handicap 12.6) in this study. Pre- and post-test investigations of golf shots made by three different clubs were conducted by use of a golf simulator. The golfers were randomized into two groups: a SMT group and a Control group. After the pre-test, the golfers in the SMT group completed a 4-week SMT program designed to improve their motor timing, the golfers in the Control group were merely training their golf-swings during the same time period. No differences between the two groups were found from the pre-test outcomes, either for motor timing scores or for golf shot accuracy. However, the post-test results after the 4-weeks SMT showed evident motor timing improvements. Additionally, significant improvements for golf shot accuracy were found for the SMT group and with less variability in their performance. No such improvements were found for the golfers in the Control group. As with previous studies that used a SMT program, this study's results provide further evidence that motor timing can be improved by SMT and that such timing improvement also improves golf accuracy. [ABSTRACT FROM AUTHOR]

The authors investigated how the force pattern exerted on a golf club is coordinated with the golfer's weight shift, which supplies power to the swing. Moderately skilled golfers (n = 10, 5–10 stroke handicap) hit short golf shots requiring different amounts of force. Across these different shots, the timing of the force pattern applied to the clubhead was approximately invariant even though the force magnitude varied. In contrast, the weight shift timing and magnitude both varied with the required force of the shot. Across repeated attempts at the same shot, temporal variations in the clubhead force pattern were either uncorrelated or only weakly correlated with temporal variations in the weight shift. Together, these data indicate that the weight shift is a relatively independent, adjustable rhythmic unit from the invariant clubhead timing pattern for moderately skilled golfers. [ABSTRACT FROM AUTHOR]

This study assessed golfers' gaze behavior in both the preparation (line reading) and execution (ball striking) of putts with different break characteristics. Six golfers completed 25 3-m putts on five different slopes (flat, 0.9° and 1.8° left-to-right, 0.9° and 1.8° right-to-left), while their gaze behavior was analyzed using an Applied Science Laboratories Mobile Eye gaze-registration system. Frame- by-frame analyses of 136 puffs were performed to assess the number and duration of fixations made during the preparation and execution phases of the puffs. Putting performance was significantly poorer for the most severe break (1.8°) than for other conditions. The only gaze variable to distinguish between successful and unsuccessful putting outcome was the quiet eye period (the final fixation prior to the initiation of the putter movement). Specifically, participants had significantly longer quiet eye periods on successful than on unsuccessful puffs. [ABSTRACT FROM AUTHOR]

Since labral pathology in professional golfers has been reported, and such pathology has been associated with internal/external hip rotation, quantifying the rotational velocity of the hips during the golf swing may be helpful in understanding the mechanism involved in labral injury. Thus, the purpose of this study was to determine the peak internal/external rotational velocities of the thigh relative to the pelvis during the golf swing. Fifteen female, collegiate golfers participated in the study. Data were acquired through high-speed three dimensional (3-D) videography using a multi-segment bilateral marker set to define the segments, while the subjects completed multiple repetitions of a drive. The results indicated that the lead hip peak internal rotational velocity was significantly greater than that of the trail hip external rotational velocity (p = 0.003). It appears that the lead hip of a golfer experiences much higher rotational velocities during the downswing than that of the trail hip. In other structures, such as the shoulder, an increased risk of soft tissue injury has been associated with high levels of rotational velocity. This may indicate that, in golfers, the lead hip may be more susceptible to injury such as labral tears than that of the trailing hip. [ABSTRACT FROM AUTHOR]

The purpose of this experiment was to study the role of binocular vision, including both stereopsis and binocular vergence, on the complex task of golf putting. The putting accuracy of 16, visually-normal, inexperienced golfers (range 23- 66 years, mean=35 years) was assessed for small (3cm) and large (12cm) targets located at 3, 6, and 9 feet with their distance corrective lenses in place. Subjects performed the task under either normal binocular or monocular viewing conditions. Putting accuracy (% successful putts) was significantly better under binocular versus monocular viewing conditions for the smaller target. This was true for 10 out of 12 (83%, p=0.019), 11 out of 12 (92%, p=0.003), and 12 out of 12 (100%, p<0.001) of the subjects for the 3-, 6-, and 9-foot test distances, respectively. The percentage improvement in putting accuracy under binocular as compared to monocular viewing conditions for the small (3cm) target was 14%, 8%, and 13% for the 3-, 6-, and 9-foot target distances, respectively. For the larger target, the trends were similar but smaller in magnitude (0.5-7%) and not statistically significant. These findings are consistent with earlier studies demonstrating improved athletic performance under binocular versus monocular viewing conditions. The additional depth-related cues provided by stereopsis and binocular vergence appear to be crucial for more precise and detailed tasks, such as were present with the smaller target. [ABSTRACT FROM AUTHOR]

This study investigated the effect of psychological pressure on physiological responses during the golf putting stroke. Six young adults (four males and two females) participated in the study. The experiment was comprised of a contest that consisted of four sessions, with a dinner prize awarded to the winner. In each session, the subject was instructed to attempt 20, 9-foot putts. Eye, head, and putter motions, as well as heart rate and breathing rate, were objectively recorded during each trial. For all sessions, each successful putt was awarded a score of +2 points. However, as the four sessions progressed, any missed putt was given progressively greater negative scores: -2, -3, -4, and -5 points, respectively. At the end of the experiment, the subject rated the perceived pressure during each session on a scale of 1 to 5, with 1 corresponding to no pressure and 5 corresponding to extreme pressure. Overall, the results demonstrated that the apparently simple act of putting involves a complex interplay among various physiological and neurological control parameters, hence reflecting a myriad of emotions that are magnified under increased psychological pressure. [ABSTRACT FROM AUTHOR]

The purpose of the present investigation was to determine the role of visual and verbal feedback on golf putting accuracy. The putting accuracy of 12, visually-normal, inexperienced golfers (range 23-66 years, mean=42 years) was assessed for small (3cm) and large (12cm) targets located 6 feet away. After a brief practice interval, subjects performed the task: under either normal viewing conditions ("control"); behind a large cardboard baffle that eliminated most of their central and peripheral visual field ("no visual or verbal feedback"); or behind the same baffle but with verbal knowledge of putt accuracy ("verbal feedback only"). There was no significant difference between any condition for both the 3cm and 12cm target. The difference in putting percentage accuracy between the three conditions ranged from 2.1%-4.6% for the 3cm target and from 0.4%-2.9% for the 12cm target. Comparison of the first 10 shots to the last 10 shots for each condition revealed no significant differences in putting performance. These findings are consistent with earlier studies demonstrating a reduced reliance on visual feedback for certain simple, repetitive, and fixed sensorimotor activities. In such tasks, visual information appears to be of less importance, once the proper force- The purpose of the present investigation was to determine the role of visual and verbal feedback on golf putting accuracy. The putting accuracy of 12, visually-normal, inexperienced golfers (range 23-66 years, mean=42 years) was assessed for small (3cm) and large (12cm) targets located 6 feet away. After a brief practice interval, subjects performed the task: under either normal viewing conditions ("control"); behind a large cardboard baffle that eliminated most of their central and peripheral visual field ("no visual or verbal feedback"); or behind the same baffle but with verbal knowledge of putt accuracy ("verbal feedback only"). There was no significant difference between any condition for both the 3cm and 12cm target. The difference in putting percentage accuracy between the three conditions ranged from 2.1%-4.6% for the 3cm target and from 0.4%-2.9% for the 12cm target. Comparison of the first 10 shots to the last 10 shots for each condition revealed no significant differences in putting performance. These findings are consistent with earlier studies demonstrating a reduced reliance on visual feedback for certain simple, repetitive, and fixed sensorimotor activities. In such tasks, visual information appears to be of less importance, once the proper force-distance paradigm has been incorporated into motor memory. Further, motor memory does not appear to dissipate with the withdrawal of visual feedback, at least in the short term. [ABSTRACT FROM AUTHOR]

Background: No fine-wire electromyography studies have been performed to compare the activity of forearm muscles in professional golfers versus amateur golfers. Hypothesis: The fine-wire electromyographic activity of forearm muscles differs between professional and amateur golfers during the different phases of the golf swing. Study Design: Controlled laboratory study. Methods: Ten male right-handed amateur golfers and 10 male right-handed professional golfers without history of elbow symptoms were tested with fine-wire electromyographic electrodes inserted into the flexor carpi radialis, pronator teres, flexor carpi ulnaris, and extensor carpi radialis brevis muscles of both forearms. Electromyographic data were synchronized with video data, and the muscle activity was expressed as a percentage of maximum manual muscle test activity for each phase of the golf swing. Results: Compared with professional golfers, amateur golfers had more muscle activity in the pronator teres of the trail arm (right arm in a right-handed golfer) in the forward swing phase (120.9% maximum manual muscle test vs 57.4% maximum manual muscle test; P = .04) and a trend toward increased activity in the acceleration phase (104.8% maximum manual muscle test vs 53.1% maximum manual muscle test; P = .08). In contrast, professional golfers had more muscle activity in the pronator teres of the lead arm (left arm in a right-handed golfer) in the acceleration phase (88.1% maximum manual muscle test vs 36.3% maximum manual muscle test; P = .03) and a trend toward increased activity in the early follow-through phase (58.1% maximum manual muscle test vs 28.8% maximum manual muscle test; P = .06). Conclusion: Pronator teres muscle activity in the golf swing differs significantly between professional and amateur golfers. Clinical Relevance: Exercises with an emphasis on stretching and strengthening of the pronator teres may be useful in treating and/or preventing medial epicondylitis in amateur golfers. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine how shaft length affects golf driving performance. A range of drivers with lengths between 1.168 m and 1.270 m, representing lengths close to the 1.219 m limit imposed by R&A Rules Limited (2008), were assembled and evaluated. Clubhead and ball launch conditions and drive distance and accuracy were determined for seven category 1 golfers (handicaps 0.21 ± 2.41) who performed shots on a purpose-built practice hole. As shaft length increased from 1.168 m to 1.270 m, initial ball velocity increased (+1.8 m/s, P < 0.01). Ball carry (+4.3 m, P = 0.152) also increased, although not significantly so. Furthermore, as shaft length increased, for all club comparisons there was no decrease in accuracy. Ball launch conditions of spin components and launch angle remained unaffected by shaft length. Launch angle increased (0.8°, F = 1.074, P = 0.362) as driver shaft length increased. Our results show that clubhead and ball velocity together with ball carry tended to increase with no loss of accuracy. [ABSTRACT FROM AUTHOR]

In the golf instructional literature, the putting stroke is typically given higher priority than green reading and aiming. The main purpose of this study was to assess the importance of the putting stroke for direction consistency in golf putting. Kinematic stroke parameters were recorded from 71 elite golf players (mean handicap = 1.8, s = 4.2) on 1301 putts from about 4 m. Of the different factors deciding stroke direction consistency, face angle was found to be the most important (80%), followed by putter path (17%) and impact point (3%). This suggests that improvements in consistency of putter path and impact point will have very little effect on overall putting direction consistency and should not be prioritized in the training of elite players. In addition, mean stroke direction variability for an elite player (European Tour) was found to be 0.39°, which is good enough to hole about 95% of all 4-m putts. In practice, however, top professionals in tournaments only hole about 17% of 4-m putts. We conclude that the putting stroke of elite golfers has a relatively minor influence on direction consistency. [ABSTRACT FROM AUTHOR]

Weight transfer research in the golf swing has produced conflicting and inconclusive results. A limitation of previous studies is the assumption that only one swing "style" exists within the golf swing. If different styles, or movement strategies, exist and if the different styles are analysed together in a single group, statistical errors will result. The aim of this study was to determine if different weight transfer styles exist in the golf swing by applying cluster analysis to centre of pressure (CP) patterns in the direction of hit (CPy) and to evaluate cluster analysis issues. Sixty-two professional to high handicap golfers performed simulated drives, hitting a golf ball into a net, while standing on two force plates. Centre of pressure position relative to the feet (CPy%) was quantified at eight swing events identified from 200-Hz video. Cluster analysis identified two major CPy% styles: a "Front Foot" style and a "Reverse" style. Both styles began with CPy% positioned evenly between the feet, moved to the back foot during backswing, and then forward during early downswing. Beyond early downswing, the Front Foot group continued to move CPy% to the Front Foot through to ball contact, while the Reverse group moved CPy% towards the back foot through ball contact and follow-through. Both weight transfer styles were evident across skill levels from professional to high handicap golfers, indicating that neither style was a technical error. Cluster analysis should include hierarchical and non-hierarchical clustering and use objective measures combined with theoretical assessment to determine the optimal number of clusters. Furthermore, a number of validation procedures should always be used to validate the solution. [ABSTRACT FROM AUTHOR]

The displacement of the golf ball struck by a driving club is affected by several player characteristics and equipment parameters and their interrelationships. Some modelling and simulation studies have shown a relationship between shaft length and clubhead speed, supported by a few experimental studies. The aim of the present study was to examine the relationship between driver length and ball launch conditions in an indoor test facility using a ball launch monitor. Nine males considered to be skilled golfers participated in the study. Four driving clubs of total length 117, 119, 124, and 132 cm were assembled from commercially available components and were used to strike golf shots while initial ball velocity, backspin rate, and launch angles were measured. Statistical analysis identified a significant difference in initial launch speed due to club length, a significant difference between participants, but no difference between the trials for a given golfer. A positive trend was noted between backspin and launch angle for all four clubs, and significant inverse associations between initial launch speed and backspin rate and launch angle. However, the combined launch conditions associated with increasing length were not considered optimal, with uncontrolled swingweight and moment of inertia effects considered to be limiting factors. [ABSTRACT FROM AUTHOR]

The golf swing has been modelled as a planar movement, but recent findings suggest that the upper limbs and golf club do not move in a single plane. However, the idea that the club alone can be swung in a single inclined plane has not been investigated mathematically. The aims of this study were to determine whether a single plane could be fitted to club motion, and if this plane varied for different clubs. Ten golfers (handicap 1 - 5) performed repeated, consistent swings with three clubs (driver, 5-iron, and pitching wedge). The motion of each club during the downswing was fitted to a single plane. The fit of the plane varied between golfers and clubs (r2 = 0.871 - 0.995, root mean square residual = 44.9 - 166.2 mm). Mean angles of the plane to the reference horizontal Z axis (driver: 125.5°, s = 3.0; 5-iron: 117.1°, s = 3.0; wedge: 113.6°, s = 2.7) and target line axis (driver: -7.8°, s = 5.9; 5-iron: -4.9°, s = 5.7; wedge: -5.9°, s = 6.0) were significantly (P < 0.05) different. Further analysis revealed a single plane was more appropriate for some participants than others, but that it might be neither desirable nor possible in some cases. [ABSTRACT FROM AUTHOR]

Dans cette étude, on a examiné l’influence de l’état des attributions et le style attributionnel (AS) sur la persistance à court-terme d’un échec perçu à une tâche de putting. 101 élèves débutants en golf ont participéà cette recherche. Deux épreuves de 8 putts ont été interrompues chacune pendant trois minutes. Durant cette période, on a mesuré la persistance individuelle en comptant le nombre de fois que le sujet essayait de putter. L’analyse des résultats montre que le style attributionnel influence la persistance à court-terme contrairement à l’état des attributions. Les sujets ayant un AS “fort contrôle personnel” font montre de plus de persistance que ceux ayant un AS “faible contrôle personnel”. Ces résultats confirment ceux obtenus lors de recherches antérieures sur les bénéfices motivationnels d’un style attributionnel “optimiste” dans des situations d’échec lors de la réalisation d’une tâche. Des attributions instables sont particulièrement bénéfiques aux sujets ayant un AS externe/incontrôlable. Ces derniers ont un niveau significativement plus élevé de persistance que les sujets ayant un AS externe/incontrôlable mais qui ont fait des attributions causales stables. This study investigated the influence of state-attributions and attributional style (AS) on short-term persistence in a putting task during perceived failure. Participants were 101 novice golf students. Two trials of eight putts each were interrupted by a 3-minute free period during which individual persistence was measured by calculating the number of putts attempted in the free period. Analyses revealed that attributional style influenced short-term putting persistence but state-attributions did not. Participants with a “high personal control” AS showed greater persistence than those with a “low personal control” AS, which supports past research on the positive motivational benefits of a more “optimistic” attributional style in task failure situations. Moreover, unstable attributions were particularly protective for individuals with an external/uncontrollable AS, in that they promoted significantly higher levels of persistence than was shown by external/uncontrollable AS individuals who made stable causal attributions. [ABSTRACT FROM AUTHOR]

This study describes a method for the measurement of sports form. The data obtained can be used for quantitative sports-skill evaluation. Here, we focus on the golf-driver-swing form, which is difficult to measure and also difficult to improve. The measurement method presented was derived by kinematical human-body model analysis. The system was developed using three-dimensional (3-D) rate gyro sensors set at positions on the body that express the 3-D rotations and translations during the golf swing. The system accurately measures the golf-driver-swing form of golfers. Data obtained by this system can be related quantitatively to skill criteria as expressed in respected golf lesson textbooks. Quantitative data for criteria geared toward a novice golfer and a midlevel player are equally useful. [ABSTRACT FROM AUTHOR]

The purpose of this study was to construct and evaluate the reliability of an apparatus for testing golf putters with respect to distance and direction deviation at different impact points on the clubface. An apparatus was constructed based on the pendulum principle that allowed putter golf clubs to swing at different speeds. The mean speed of the club head before ball impact, and of the ball after impact, was calculated from time measurements with photocells. A pin profile rig was used to determine the directional deviation of the golf ball. Three different putters were used in the study, two that are commercially available (toe-heel weighted and mallet types) and one specially made (wing-type) putter. The points of impact were the sweet spot (as indicated by the manufacturer's aim line), and 1, 2 and 3 cm to the left and right of the sweet spot. Calculation of club head speed before impact, and of ball speed after impact (proportional to distance), showed errors ⩽ 0.5% of interval duration. The variability in ball impacts was tested by measuring time and direction deviations during 50 impacts on the same ball. The mean duration (± s ) after ball impact in the test interval (1.16 m long) was 206 (0.8) ms and the standard deviation in the perpendicular spreading of the balls in relation to the direction of the test interval was 0.005 m. A test - retest of one putter on two consecutive days after remounting of the putter on the test apparatus showed less than 1% difference in distance deviation. We conclude that the test apparatus enables a precise recording of distance and direction deviation in golf putters as well as comparisons between different putters. The apparatus and set-up can be used in the laboratory as well as outdoors on the putting green. [ABSTRACT FROM AUTHOR]

Researchers have investigated the relationship between different shot-making measures and performance on the PGA Tour. Prior studies have typically focused on a short period of time or used a restricted sample so long-term trends were not discernible. To remedy this situation, the present study looked at the longitudinal performance of professional golfers from 1990-2004. The findings indicated a remarkable stability in terms of the relative importance of Greens in Regulation and Putting Average in explaining the variability in Scoring Average. The findings also indicated a declining importance of driving in recent years due, in part, to a strengthening of the negative relationship between Driving Distance and Driving Accuracy. [ABSTRACT FROM AUTHOR]

Previous planar models of the downswing in golf have suggested that upper limb segments (left shoulder girdle and left arm) move in a consistent fixed plane and that the clubhead also moves only in this plane. This study sought to examine these assumptions. Three-dimensional kinematic analysis of seven right-handed golfers of various abilities (handicap 0 - 15) was used to define a plane (named the left-arm plane) containing the 7th cervical vertebra, left shoulder and left wrist. We found that the angles of this plane to the reference horizontal z axis and target line axis (parallel to the reference x axis) were not consistent. The angle to the horizontal z axis varied from a mean of 133° (s = 1°) at the start of the downswing to 102° (s = 4°) at impact, suggesting a "steepening" of the left-arm plane. The angle of the plane to the target line changed from - 9° (s = 16°) to 5° (s = 15°) during the same period, showing anticlockwise (from above) rotation, although there was large inter-individual variation. The distance of the clubhead from the left-arm plane was 0.019 m (s = 0.280 m) at the start at the downswing and 0.291 m (s = 0.077 m) at impact, showing that the clubhead did not lie in the same plane as the body segments. We conclude that the left arm and shoulder girdle do not move in a consistent plane throughout the downswing, and that the clubhead does not move in this plane. Previous models of the downswing in golf may therefore be incorrect, and more complex (but realistic) simulations should be performed. [ABSTRACT FROM AUTHOR]

The article presents an overview of the study the influence of time preparation on putting performance as a function of skill level and familiarity of participants with the golf tool. It indicates that golf participants of the study were instructed to take time needed to be accurate or putt as fast as possible while still being accurate. The study measures the putting performance and putting time of the participants.

The effect of kinesthetic practice was investigated for its effectiveness in refining a gross motor skill. The golf swing, using a 7-iron club, served as the motor skill to be tested. A 2 (Group [kinesthetic; self-guided]) x 4 (Test [Pretest; Posttest 1, Posttest 2, and Posttest 3]) mixed factorial design was employed. Twenty-four novice golfers participated in the study and were randomly assigned to either the kinesthetic or self-guided practice group. A launch monitor system was used to obtain measures of club head speed, club face angle, and tempo to quantify baseline performance and any subsequent change in performance following the experimental procedures. The pretest involved recording 12 swings to establish baseline swing characteristics. The kinesthetic practice group then received one 20-min practice session using the Explanar golf training system. Alternately, the self-guided practice group had 20 min to practice by hitting golf balls independent of any formal instruction. The self-guided group did, however, have access to feedback from the launch monitor after each practice swing. Immediately following the practice session, the participants performed Posttest 1. Posttest 2 was administered after a 10-min break, and the third and final posttest was administered 1 week later. Our data revealed that kinesthetic practice was superior to self-guided practice for improving golf swing characteristics. For example, it was determined that kinesthetic practice led to significant increases in club head speed along with a significant and more desirable slowing in overall swing tempo. In addition, a variability analysis supported the conclusion that kinesthetic practice leads to more consistent performances throughout the each of the posttest sessions. Our final retention test indicated that the improvements observed after 10 min persisted over the course of a week. [ABSTRACT FROM AUTHOR]

The article reports on the results of research which was conducted in an effort to determine whether playing golf with titanium drivers can result in hearing loss. The research, which was conducted in response to the case of a 55 year old man with mild hearing loss who used a titanium golf club, found that titanium drivers may produce sufficient sound to induce cochlear damage. As a result of the research, researchers suggested that caution should be exercised by golfers who play regularly with titanium drivers to avoid damage to their hearing.

The article discusses the significance of Math to Phil Mickelson's profession in the U.S. He went to Congress and explains the importance of math to his profession. According to Mickelson, he use the statistics to maximize his practice. He testified before the House Education and Labor Committee on industry-backed efforts to improve science and math education. He donated his time, money and name to the academy, wherein he trained 1400 teachers from grade three to five in a one-week summer sessions.