SCIENTIFIC PUBLICATIONS

The paper reports the characteristics of joint forces for 9 activities in 18 normal healthy subjects. Activities included Walk, Walk Turn, Stand to Sit, Sit to Stand, Squat, Stand Reach, Kneel Reach, Lunge, and Golf Swing. Within the cohort ∼30% variability occurred in the manner in which each activity was completed. Within the activities the average maximum load characteristics varied in magnitude (0.5-6.4 ρBWT) and also in duration (0.96-5.89 s.) when compared to walking (3.1 ρBWT,1.1 s.). The corresponding impulse ranged from 1.6 during the Walk to 6.7 ρ.BWT.s for the Golf Swing . As high loads with low sliding velocities have been shown in the literature to be damaging to the tribology of compliant contact surfaces the findings are postulated by the authors to be specifically important for the pre-clinical testing of cartilage substitutional materials. Note: Force was normalized to body weight (ρBWT) throughout the study.

Suhara, H, Nariai, M, Takagi, T, Akiyama, K, Nagashima, J, and Shiraki, H. Relationship of clubhead speed with explosive power and muscle strength of the hip and trunk joints of elite golfers. J Strength Cond Res XX(X): 000-000, 2022-In golf, the driving distance of the ball is affected by the clubhead speed (CHS) on impact. We aimed to clarify the relationship between CHS and explosive power and muscle strength of the hip and trunk muscles in elite golfers (male age: 19.6 ± 1.9 years, male handicap: 4.4 ± 0.9, female age: 17.7 ± 1.4 years, and female handicap: 6.2 ± 0.7). A correlational design was used to assess the relationships between CHS and strength (hip extension-flexion and trunk rotation of peak torque at an isokinetic 60 and 180°·s-1 angular velocity) and CHS and power (countermovement jump [CMJ]; peak power and jump height; backward overhead medicine ball [BOMB] throw). Fourteen each of male and female elite golfers were included. The CHS during the golf swing was measured using a Doppler radar measurement device (Trackman). A correlation analysis between each measurement and CHS (p ≤ 0.05) was conducted. We found that the peak torque of right hip extension at an angular velocity of 180°/s (male, r = 0.67; female, r = 0.61), peak CMJ power (male: r = 0.63, female: r = 0.75), and BOMB throw distance (male, r = 0.6; female, 0.6) were positively correlated with CHS in both male and female golfers. These results suggest that the extensor strength of the lower extremities and trunk, centered on the hip joint in the sagittal plane, is important for physical fitness and muscle strength measurement related to CHS. Conversely, concentric trunk rotator strength and CHS were not correlated, suggesting that concentric trunk rotator strength may not be actively involved in CHS.

As the modern golf swing has changed, the incidence of knee pain in professional golfers is increasing. For those with previous knee injuries, developing a golf-swing modification that reduces knee loading may be necessary to recover performance after injury. The purpose of this study was to test whether ball position modification reduces knee joint load in a golf swing. Thirteen male professional golfers participated in the study. Golf swings were captured using a three-dimensional motion capture system and two force platforms, with conditions for self-selected ball position and eight additional ball positions. Knee internal rotation and adduction moments were calculated. The length of one golf ball (4.27 cm) backward ball position (closer to the golfer) significantly reduced the peak internal rotation moment of the lead knee (- 13.8%) (p < 0.001) and the length of one golf ball (4.27 cm) away from the target ball position significantly reduced the peak adduction moment of the lead knee (- 11.5%) (p < 0.001) compared with that of the self-selected ball position. Based on these observations, we conclude that the backward ball position modification might be suggested for golfers with anterior cruciate ligament injuries, and the away from the target modification might be suggested for golfers with medial compartment knee osteoarthritis.

Golf is a sport that can be played by an athlete of any age, which enhances its popularity. Each golfer's swing is unique, and there is no "right" way to swing the golf club; however, the professional golfer often has more of a consistent swing as opposed to an amateur golfer. A collaborative, team approach involving the golfer with a swing coach, physical therapist, and physician often can be informative on how to prevent golf injury, but also how to treat golf injury if it occurs.

The purpose of this study was to compare swing time and golf club angle parameters during golf swings using three, two dimensional (2D) low cost, Augmented-Video-based-Portable-Systems (AVPS) (Kinovea, SiliconCoach Pro, SiliconCoach Live). Twelve right-handed golfers performed three golf swings whilst being recorded by a high-speed 2D video camera. Footage was then analysed using AVPS-software and the results compared using both descriptive and inferential statistics. There were no significant differences for swing time and the golf phase measurements between the 2D and 3D software comparisons. In general, the results showed a high Intra class Correlation Coefficient (ICC > 0.929) and Cronbach's Coefficient Alpha (CCA > 0.924) reliability for both the kinematic and temporal parameters. The inter-rater reliability test for the swing time and kinematic golf phase measurements on average were strong. Irrespective of the AVPS software investigated, the cost effective AVPS can produce reliable output measures that benefit golf analyses.

Using ultrasound biofeedback in conjunction with verbal cueing can increase muscle thickness more than verbal cueing alone and may augment traditional rehabilitation techniques in an athletic, physically active population. Brightness mode (B-mode) ultrasound can be applied using frame-by-frame analysis synchronized with video to understand muscle thickness changes during these dynamic tasks. Visual biofeedback with ultrasound has been established in static positions for the muscles of the lateral abdominal wall. However, by securing the transducer to the abdomen using an elastic belt and foam block, biofeedback can be applied during more specific tasks prevalent in lifetime sports, such as golf. To analyze muscle activity during a golf swing, muscle thickness changes can be compared. The thickness must increase throughout the task, indicating that the muscle is more active. This methodology allows clinicians to immediately replay ultrasound videos for patients as a visual tool to instruct proper activity of the muscles of interest. For example, ultrasound can be used to target the external and internal obliques, which play an important role in swinging a golf club or any other rotational sport or activity. This methodology aims to increase oblique muscle thickness during the golf swing. Additionally, the timing of muscle contraction can be targeted by instructing the patient to contract the abdominal muscles at specific time points, such as the beginning of the downswing, with the goal of improving muscle firing patterns during tasks.

The aim of this study was to compare swing kinematic differences between women and men and investigate which variables predict clubhead speed (CHS) and carry distance (CD) whilst accounting for individual variation.

Sixty million golfers around the world play golf. Golf injuries are most frequently located in the spine, elbow, wrist, hand and shoulder. Those injuries are often seen in golfers with more playing hours and suboptimal swing biomechanics, resulting in overuse injuries. Golfers who do not perform a warm-up or do not warm-up appropriately are more likely to report an injury than those who do. There are several ways to warm-up. It is unclear, which warm-up is most useful for a golfer to perform. Moreover, there is currently no evidence for the effectiveness of a warm-up program for golf injury prevention. We previously have developed the Golf Related Injury Prevention Program (GRIPP) intervention using the Knowledge Transfer Scheme (KTS). We aim to evaluate the effect of the GRIPP intervention on golf-related injuries. The hypothesis is that the GRIPP intervention program will reduce the number of golf-related injuries.

Golf is one of the most popular sports among seniors. Here, we report the case of a 76-year-old woman who developed a vertebral fracture while playing golf. The patient had been suffering from leg pain for several years but developed sudden back pain after her golf swing. Because magnetic resonance imaging demonstrated a new vertebral fracture of the L1 vertebral body and canal stenosis at the L4/5 level, she successfully underwent L1 vertebroplasty and L4/5 decompression. For older golfers, a classical swing that twists the pelvis and shoulders at the same time may be recommended.

Golf is a popular sport played worldwide. The majority of professional golfers work as teaching professionals based at golf clubs. All professional players spend numerous hours on the golf course, placing themselves at increased risk of injury. There have been no recent, large studies investigating injury patterns among male and female professional golfers.

Numerous studies have been conducted to investigate golf swing performance in both preventing injury and injury occurrence. The objective of this review was to describe state-of-the-art golf swing biomechanics, with a specific emphasis on movement kinematics, and when possible, to suggest recommendations for research methodologies. Keywords related to biomechanics and golf swings were used in scientific databases. Only articles that focused on golf-swing kinematics were considered. In this review, 92 articles were considered and categorized into the following domains: X-factor, crunch factor, swing plane and clubhead trajectory, kinematic sequence, and joint angular kinematics. The main subjects of focus were male golfers. Performance parameters were searched for, but the lack of methodological consensus prevented generalization of the results and led to contradictory results. Currently, three-dimensional approaches are commonly used for joint angular kinematic investigations. However, recommendations by the International Society of Biomechanics are rarely considered.

This is the first study that presents electromyographic measurements prior to the development of lower back pain in young elite golfers.

BACKGROUND We investigated the effects of the upper-body flexibility exercises on the golf performance of a female amateur golfer. CASE REPORT The participant was a 43-year-old woman who performed a general golf swing exercise (30 min) and an upper-body flexibility exercise (20 min) 3 times a week, for a total of 6 times in 2 weeks. The maximum rotation angle of the upper body was measured using a goniometer. To measure the X-factor, the numerical value was measured after subtracting the rotation angle of the lower-body from the rotation angle of the upper body when the participant stopped making a back-swing top motion. A camera measuring instrument was used to measure the clubhead speed and carry distance of the golf ball when she hit the ball with a no. 7 iron club. After the exercises, the maximum rotation angle of the participant's upper body increased from 40° to 69°, and the X-factor increased from 10° to 24°. The clubhead speed increased from 29.4 m/s to 34.4 m/s, and the carry distance increased from 84 m to 106 m. CONCLUSIONS The participant responded positively to the upper-body flexibility exercises, and there was improved upper-body mobility, X-factor, clubhead speed, and carry distance. Our results showed that upper-body flexibility exercises with a general golf swing exercise for female amateur golfers may improve golf performance.

Improving golf fitness is one way to improve club head velocity and subsequently golf performance. The purpose of the study was to investigate the effect of a three-week upper-body sprint training (SIT) program on power output and golf performance.

It has previously been argued that science has only made a limited contribution to the sport of golf, particularly the human element. This lack of impact could, in part, be attributed to the absence of an appropriate theoretical framework in most empirical investigations of the golf swing. This position paper outlines an ecological-dynamical approach to golf science that is better able to capture the interactions among the many structural parts of a golfer, and the relations between a golfer, his or her equipment, and his or her surrounding environment than other theoretical approaches have hitherto. It is proposed that the conjoining of principles and concepts of ecological psychology and dynamical systems theory could make a significant contribution to the enhancement of knowledge and understanding of swing biomechanics, club design and customisation, and coaching practice. This approach could also provide a platform on which to integrate the various subdisciplines of sport and human movement science to gain a more holistic understanding of golf performance.

Narrative review.

Langdown, BL, Bridge, MW, and Li, F-X. The influence of an 8-week strength and corrective exercise intervention on the overhead deep squat and golf swing kinematics. J Strength Cond Res XX(X): 000-000, 2022-It has previously been suggested that performance of the overhead squat (OHS) is a useful predictor of loss of posture in the golf swing. Using an 8-week intervention to improve OHS performance, this study assessed this suggestion and analyzed the impact of any resultant physical adaptations on golf swing kinematics. Thirty-seven golfers (handicap = 14.8 ± 13.3) were randomly split into a control group (n = 16) and an intervention group (n = 21)-who completed an 8-week strength and flexibility program. Pre- and postintervention OHS assessments and 3-dimensional (3D) 6-iron swing kinematics were captured. The level of significance set for the study was p < 0.05. Despite the intervention group's significant improvement in OHS thigh angle (p < 0.001), there were no significant changes in 3D swing kinematics between the groups and over pre- and posttesting for address (p = 0.219), top of the backswing (p = 0.977), and impact (p = 0.994). In addition, regression analysis revealed that the 4 measured OHS variables were significant and small predictors of swing kinematic variables at the top of backswing and impact (ranging from R2 = 0.109 to R2 = 0.300). These may, however, be spurious relationships as swing changes could be expected following the intervention if they were indeed true predictors of the postural variables. The use of the OHS to understand the cause of loss of posture during the golf swing is therefore not recommended because many other variables could influence swing kinematics. It may, however, be a useful assessment tool for strength and range of movement, provided that any motor learning issues are resolved before results influencing conditioning programs.

When using a bimanual tool to strike an object, most people place their preferred hand closer to the striking end. In sports, a player is deemed to adopt a "right- or left-handed" stance depending on the hand that is lower on the club or bat. Research has suggested there is an advantage in going against this convention by placing the preferred hand at the top in a "reversed-stance". This study aimed to establish if the reversed-stance advantage exists in golf, whether it is underpinned by the preferred hand or dominant eye, and why players adopt such a stance. We tested hand preference, eye dominance, and full swing stance in 150 golfers (30 for each handicap category) and conducted follow-up interviews with 12 reversed-stance players. Professional or category 1 golfers were 21.5 times more likely to adopt a reversed-stance. The advantage could not be explained by ambidexterity or the dominant eye but could be explained by the position of the preferred hand. Reversed-stance players cited a variety of reasons for adopting it and were more likely to display a left-hand preference. Findings offer initial evidence of a reversed-stance advantage in golf and can inform work identifying its origins and mechanisms.

McHugh, MP, O'Mahoney, CA, Orishimo, KF, Kremenic, IJ, and Nicholas, SJ. Importance of transverse plane flexibility for proficiency in golf. J Strength Cond Res 36(2): e49-e54, 2022-The extent to which the flexibility requirements for golf proficiency vary between the planes of motion has not been examined. The purpose of this study was to compare flexibility between proficient and average golfers with the hypothesis that proficient golfers have greater transverse plane flexibility than average golfers, with no differences in the sagittal and frontal planes. Twenty-five male golfers were categorized as proficient (handicap ≤5, n = 13) or average (handicap 10-20, n = 12). Fourteen flexibility tests were performed (4 shoulder tests, 4 trunk tests, and 6 hip tests) with tests in all 3 planes of motion for each body segment. In addition, trunk motion, pelvic motion, and hip motion during the golf swing were assessed with high-speed motion analysis. Ball speed and shot distance were recorded with a golf simulator. Proficient golfers had significantly better flexibility than average golfers in the transverse plane (shoulder p = 0.021, trunk p = 0.003, and hip p < 0.0001), with no differences in the sagittal plane or frontal plane (plane of motion by golf proficiency p = 0.0001). Transverse plane hip flexibility accounted for 48% of the variability in ball speed (p < 0.0001) and 45% of the variability in total distance (p = 0.001). During the golf swing, proficient golfers had greater separation between the pelvis and the trunk (x-factor) than average golfers (p = 0.002). In conclusion, transverse plane flexibility in the trunk and hips is an important requirement for golf proficiency. Sagittal plane flexibility and frontal plane flexibility were unrelated to proficiency. Developing and maintaining trunk and hip rotation flexibility is important for optimizing performance.

Return to sports after joint arthroplasty is mainly evaluated for lower limbs procedures. When a return to a specific sport is mentioned, no technical approach nor level consideration are specified. We suggested that patients who undergo total shoulder arthroplasty will be able to maintain playing golf at same high level.

The biomechanics of the golf swing have received considerable attention in previous research. However, existing studies have focused on young athletes, while the kinematics of older golfers remain poorly documented. This study presents kinematic data for healthy senior golfers during swings performed with a driver and six-iron. Seventeen male golfers (62.2 ± 8.8 years) volunteered for participation and a 10-camera Vicon system (Oxford, UK) recorded kinematic data (500 Hz). A launch monitor (TrackMan, Vedbæk, Denmark) recorded club head speed and initial ball speed. Joint angles and peak velocities of the trunk and lower body were extracted at the top of the backswing, ball contact, and end of the swing. Intraclass correlations and standard error of measurement determined reliability, and pairwise statistics determined between-club differences. Swings with the driver had 7.3° less trunk extension and 4.3° less X-factor at backswing, and 10.5° less trunk flexion and 3.2° less X-factor at ball impact. Older adults portray several differences in lower body kinematics between a six-iron and driver but maintain good to excellent reliability (0.728-0.997) during the swings. Comparisons with previous research also showed senior athletes produce slower club head and ball speeds than younger golfers, and that kinematic differences exist between the populations.

Sheehan, WB, Bower, RG, and Watsford, ML. Physical determinants of golf swing performance: A review. J Strength Cond Res 36(1): 289-297, 2022-Traditionally, golf practice has primarily focused on the mental, technical, and skill aspects as the primary means to improve performance. Only recently has a greater emphasis been placed on the physical components with balance, muscular strength, power, and specific muscle-tendon properties demonstrating positive associations with club head speed and carry distance. Accordingly, this review will explore the influence of these physical components on measures of golf swing performance. Superior balance may allow players to effectively deal with the need to shift weight during the swing as well as different stance positions, whereas superior lower-body muscular strength, power, and stiffness may allow more mechanical work to be performed on the club during the swing per unit of time, consequently increasing club head speed. Alternatively, flexibility may also contribute to enhanced force production with a greater range of motion, particularly when generating the "X-factor," allowing for a longer backswing and more time to produce higher angular velocities and forces. Furthermore, training intervention studies focusing on the aforementioned components have demonstrated enhancements in swing performance. Targeting multiple muscle groups, including those implicated via electromyography activation, and utilizing multiple modalities have proven effective at increasing club head speed. However, such multifaceted programs have made it difficult to determine the mechanisms that specifically contribute to performance gains. Despite these limitations, strength, power, and musculotendinous stiffness, particularly in the lower body, seem to be stronger determinants of club head speed and carry distance than flexibility. Furthermore, acute improvements can be induced using resistance-orientated warm-ups.

The purpose of this study was to investigate the linear relationships among the hand/clubhead motion characteristics in golf driving in skilled male golfers (n = 66; handicap ≤ 3). The hand motion plane (HMP) and functional swing plane (FSP) angles, the HMP-FSP angle gaps, the planarity characteristics of the off-plane motion of the clubhead, and the attack angles were computed from the drives captured by an optical motion capture system. The HMP angles were identified as the key variables, as the HMP and FSP angles were intercorrelated, but the plane angle gaps, the planarity bias, and the attack angles showed correlations to the HMP angles primarily. Three main swing pattern clusters were identified. The parallel HMP-FSP alignment pattern with a small direction gap was associated with neutral planarity and planar swing pattern. The inward alignment pattern with a large inward direction gap was characterized by flat planes, follow-through-centric planarity, spiral swing pattern, and inward/downward impact. The outward alignment pattern with a large outward direction gap was associated with steep planes, downswing-centric planarity, reverse spiral swing, and outward/upward impact. The findings suggest that practical drills targeting the hand motion pattern can be effective in holistically reprogramming the swing pattern.

The purpose of this study was to assess the weight shift and X-Factor values of golfers with lower limb loss.

The aim of the study was to examine changes in centre of pressure (COP) movement, alignment and shot outcome during golf shots from flat, uphill, and downhill slopes by mid-handicap golfers. Twelve male golfers hit balls with a six-iron from the flat and 5° slopes while kinematics and kinetics of the swing were collected. A launch monitor measured performance outcomes. A shift in the COP was found during the backswing when playing on a slope, but disappeared during the downswing. Golfers attempted to align the body perpendicular to the slope at the start of the swing resulting in COP movement towards the lower foot, but were not able to maintain this throughout the swing, like low handicap golfers. There was no significant difference in stance width, but golfers placed the ball closer to the uphill foot on a slope. Ball speed was not significantly affected by the slope, but launch angle and ball spin were. Golfers were more likely to hit shots to the left from an uphill slope and to the right for a downhill slope. No consistent compensatory adjustments in alignment at address were found, with differences in final ball position due to lateral spin.

Jermyn, S, Neill, CO, and Coughlan, EK. The acute effects from the use of weighted implements on skill enhancement in sport: A systematic review. J Strength Cond Res 35(10): 2922-2935, 2021-Weighted implements are used before competitive performance with the aim of enhancing motor skill execution on return to the standard implement. The purpose of this review was to analyze the existing literature pertaining to the acute effects of weighted implements on respective sporting performance. Following a systematic screening process, 25 studies were identified. This review highlighted the effects of (a) weighted balls and bats on throwing and batting performance and (b) indoor weight throw implements on indoor weight throw performance. Studies reported conflicting effects on immediate performance post-warm-up with the respective implements. Notably, although overweighted bats and overweight attachments are a prominent preparatory tool in baseball, this review found consistent and repeated evidence of degraded batting performance in striking-based studies. Decreased bat velocity, altered swing patterns, subjective-objective mismatches of bat speed and weight, temporal accuracy errors, and inadequate recalibration to the standard bat were identified as acute effects. This review identified an obvious dearth of research into the acute effects of weighted implements on motor skills in other sports with equally complex perceptual motor patterns, such as football (soccer), golf, rugby, basketball, and American football. Future weighted implement research should investigate the acute effects of respective implements on motor skill performance in other sports, such as those aforementioned, with the purpose of exploring relevant implications for preparatory strategies and immediate performance on return to the standard implement.

: To study whether novices can use sonification to enhance golf putting performance and swing movements. : 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. : 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. : 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.

The purpose of this study was to identify the dynamic factors contributing to pelvis angular velocity about its longitudinal axis (pelvis axial angular velocity) during the golf swing. Thirty-one right-handed skilled golfers (handicap, 3.5 ± 1.8) performed swings with a driver. The kinematic and kinetic data were collected using an optical motion analysis system and two force platforms. The dynamic factors (i.e., joint torque, gravitational force, motion-dependent forces and inertia forces) contributing to pelvis axial angular acceleration were calculated. The present study revealed that the left (lead) hip flexor and adductor torques as well as the right (trail) hip extensor and abductor torques were identified as the main contributors to pelvis axial angular velocity. These hip joint torques contributed not synchronously but sequentially to the pelvis. Although the knee joint torques contributed little to pelvis axial angular velocity directly, the knee joint torques might support the generation of large hip joint torques by regulating joint postures. These findings indicate that the functional coordination of the lower limb segments as well as the magnitude of the joint torques play an important role in rotating the pelvis.

Traditionally, spontaneous cervical artery dissections have been associated with violent, sudden neck movements. These events are a significant cause of stroke related morbidity, particularly in young people. Only a handful of cases of golf-induced vertebral artery dissection (VAD) have been described, and the discussion has primarily focused on middle-aged men. Despite the discussion focused on this demographic, women are participating in golf at higher rates than ever before, and have a higher risk for developing VAD.

The golf swing has been associated with mechanical injury risk factors at many joints. One swing, the Minimalist Golf Swing, was hypothesised to reduce lumbar spine, lead hip, and lead knee ranges of motion and peak net joint moments, while affecting swing performance, compared to golfers' existing swings. Existing and MGS swings of 15 golfers with handicaps ranging from +2 to -20 were compared. During MGS downswing, golfers had 18.3% less lumbar spine transverse plane ROM, 40.7 and 41.8% less lead hip sagittal and frontal plane ROM, and 39.2% less lead knee sagittal plane ROM. MGS reduced lead hip extensor, abductor, and internal rotator moments by 17.8, 19.7 and 43%, while lead knee extensor, abductor, adductor and external rotator moments were reduced by 24.1, 26.6, 37 and 68.8% respectively. With MGS, club approach was 2° shallower, path 4° more in-to-out and speed 2 m/s slower. MGS reduced certain joint ROM and moments that are linked to injury risk factors, while influencing club impact factors with varying effect. Most golf injuries are from overuse, so reduced loads per cycle with MGS may extend the healthy life of joints, and permit golfers to play injury-free for more years.

Low back pain is one of the most common conditions occurring in the golfing population. Many approaches have been utilized throughout the years to address this condition including the concept of regional interdependence. The purpose of this case report is to describe the evaluation process and treatment approach of a golfer with low back pain using the principles of regional interdependence.

Golf swing analysis is common in both recreational and professional levels where players are searching for improvements in shot accuracy and distance. The use of motion analysis systems such as the portable Polhemus Liberty system is gaining interest by coaches and players; however, to date, no research has examined the usefulness of the Polhemus Liberty system for golf swing analysis. Therefore, the purpose of this study was to determine the reliability of the Polhemus Liberty system and validity compared to the VICON Nexus motion analysis system when assessing segment (pelvis and thorax) and joint (shoulder, elbow and wrist) angular kinematics during a golf swing at key events (address, top of backswing and impact). Fifteen elite amateur/professional golfers performed ten golf swing trials within specified bounds using their 5-iron club. Reliability was assessed using interclass coefficient, effect size and -test statistics by all participants completing two separate testing sessions on separate days following the same experimental protocol. Validity was assessed using effect size, Pearson correlation and -test statistics by comparing swings captured using both Polhemus Liberty and VICON Nexus concurrently. Results demonstrated no difference in ball outcome results using the Trackman launch monitor ( > 0.05) and that the Polhemus Liberty system was reliable across the two sessions for all segment (pelvis and thorax) and joint (lead shoulder (gleno-humeral joint), elbow and wrist) angular kinematics ( > 0.05). Validity analysis showed that the Polhemus Liberty system for the segments (pelvis and thorax) and joints (lead shoulder and wrist) were different compared to the VICON Nexus data at key events during the golf swing. Although validity could not be confirmed against VICON Nexus modeling, the Polhemus Liberty system may still be useful for golf swing analysis across training sessions. However, caution should be applied when comparing data from the system to published research data using different motion analysis methods.

The purpose of this study was to investigate whether low-handicap elite golfers with chronic low back pain (CLBP) exhibit deficits in dynamic postural control and whether CLBP affects golfers in terms of their golf swing parameters. A total of fifteen Division 1 college golfers were recruited as participants. Of these, six of whom experienced CLBP, while the remaining participants were healthy. In this study, CLBP was defined as experiencing chronic pain symptoms for more than six months. The Star Excursion Balance Test (SEBT) was administered to examine dynamic posture control in both groups. The TrackMan Golf Launch Monitor Simulator was used to collect data on the performance parameters of the swing of the participants. The results for both feet in the medial, lateral, posterior, posteromedial, and posterolateral directions indicated that the CLBP group scored lower than the control group. However, the CLBP group scored higher for the right foot in the anterolateral direction. The parameters for the club speed and ball carry of the CLBP group were lower than those of the control group. Further, the CLBP group exhibited a more upright swing plane relative to the control group. Taken together, our findings suggest that SEBT may be feasible and highly accessible to assess golf swing performance of elite players with CLBP.

As physical fitness has become more of a central component of competitive golf it is important to have an understanding of the relationship between anthropometric and physical performance on actual golf performance. Thus, the purpose of this investigation was to determine the relationship between measures of anthropometrics and physical performance to golf swing performance.

The object of this study was to examine return to golf and changes in golf performance after shoulder arthroplasty. Additionally, we set out to determine if there were differences in return to play and performance between total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RTSA). We also examined pain during the golf swing to determine if there is a change in pain level after surgery.

Analyses of segment kinetic energy (KE) can provide the most appropriate means of exploring sequential movements. As the reliability associated with its measurement has not been reported, the aim of this study was to examine the test-retest reliability of segment KE measures in the golf swing. On two occasions, seven male golfers hit five shots with three different clubs. Body segment inertia parameters were estimated for 17 rigid bodies and 3D kinematic data were collected during each swing. The magnitude and timing of peak total, linear and angular kinetic energies were then calculated for each rigid body and for four segment groups. Regardless of club type, KE was measured with high reliability for almost all rigid bodies and segment groups. However, significantly larger magnitudes of peak total (= 0.039) and linear (= 0.021) lower body KE were reported in test 2 than in test 1. The high reliability reported in this study provides support for the use of analyses of segment kinetic energy. However, practitioners should pay careful attention to the identification of anatomical landmarks which define the thigh, pelvis and thorax as this was the main cause of variability in repeated measures of segment kinetic energy.

The increasing interest in the biomechanical analysis of the golf swing warrants establishing the minimum number of trials required to obtain reliable data. Several such methods have been suggested previously for other movement tasks, and it has been shown that the number of required trials depends on the method used and on the task examined. This study aimed to compare three methods of reliability: a sequential average, intraclass correlations, and a modified version of the standard error of measurement (SEM). Kinematic and kinetic data of 10 recreational golfers performing 15 shots with both a six-iron and a driver was collected using a ten-camera motion capture system and force platforms. Range-of-motion, velocity, joint moments, and ground reaction forces were extracted and analysed using the three methods. The sequential average method yielded the highest number of required trials (12), while the intraclass correlations and SEM both resulted in lower numbers of required trials (4). Considering the variability between participants and strengths and limitations of the various methods, we conclude that 8 trials is sufficient for biomechanical analyses of a golf swing and recommend the SEM method for determining how many swings should be collected.

High-level golfers use various warm-up strategies to enhance clubhead and ball speed, including weighted equipment. We investigated the acute effects of the SuperSpeed Golf™ weighted-club warm-up on clubhead, ball, and swing kinematics, and the persistence of any acute effects in subsequent sets. Twelve competitive golfers (handicap < 3.0) completed five sets of five swings using their own drivers under two randomised warm-up conditions (Control and SuperSpeed). We compared swing, peak segment and club angular velocity, and centre of mass (COM) parameters collected using a 3D motion capture system (500 Hz) between conditions. The temporal persistence of any meaningful (Cohen's ≥ ) and significant (≤ 0.05) effect detected in the first set was investigated in subsequent sets. SuperSpeed led to significant changes in clubhead speed (2.6 mph); downswing time; peak angular velocities of the torso, lead arm, and club; and two COM variables in the initial set. There was no significant change in ball speed, resulting in a negative change in smash factor acutely ( - 0.82, = 0.009). Nearly all changes observed were no longer meaningful or significant in subsequent sets. Overall, golfers can expect an increase in driving clubhead speed on the first tee using the SuperSpeed Golf™ vs Control warm-up, with trivial effects from the second tee onwards.

The prevalence of spondylolysis amongst adolescent athletes presenting with low back pain has been reported as high as 47-55%. Youth athletes participating in sports involving movements combining compression, extension and rotation appear most susceptible. As such, young golfers are a high-risk group, particularly given the high shear and compressive forces associated with the golf swing action. This is compounded by a culture which encourages very high practice volumes, typically poorly monitored. Although non-operative interventions are deemed the gold-standard management for this condition, surgery is indicated for more severe presentations and cases of 'failed' conservative management. The case presented herein outlines an inter-disciplinary, non-operative management of a 17-year old elite golfer with a moderate to severe presentation. A 4-stage model of reconditioning is outlined, which may be of use to practitioners given the paucity of rehabilitation guidelines for this condition. The report highlights the benefits of a graded program of exercise-based rehabilitation over the typically prescribed "12 weeks rest" prior to a return to the provocative activity. It also supports existing evidence that passive therapeutic approaches should only be used as an adjunct to exercise, if at all in the management of spondylolysis. Finally, and crucially, it also underlines that to deem non-surgical rehabilitation 'unsuccessful' or 'failed', clinicians should ensure that (long-term) exercise was included in the conservative approach.

Gould, ZI, Oliver, JL, Lloyd, RS, Neil, R, and Bull, M. The golf movement screen is related to spine control and x-factor of the golf swing in low handicap golfers. J Strength Cond Res 35(1): 240-246, 2021-The aim of the study was to investigate the association between the golf movement screen (GMS), x-factor, which is the separation between the upper torso and pelvis rotation, and biomechanical movements of the pelvis, thorax, and spine during the backswing and impact of a golf shot in low handicap golfers. In total, 62 golfers were involved in this study (n = 40 male, n = 22 female); the mean age of the sample was 15.4 ± 2.4 years. For the GMS, all subjects were assessed on their movement ability over a total of 10 different exercises. After a thorough warm-up routine of practice swings, each golfer then performed a single trial for biomechanical analysis. Biomechanical data were collected using an electromagnetic tracking system. Four of the 10 exercises had a significant correlation with x-factor (r = 0.25-0.33; p < 0.05). Four exercises had moderate correlations with spine rotation at the top of backswing. Spine side bend had a significant correlation with 9 of the 10 exercises and total GMS score (r = 0.26-0.53, p < 0.05). Movements of the pelvis and thorax at the top of backswing had minimal associations with the GMS. At impact, trunk inclination, thoracic rotation, and squat had small to moderate significant relationships with biomechanical movements (p < 0.05). Movement competency, as measured by the GMS, is associated with important aspects of swing mechanics. In particular, golfers who achieve better scores in the GMS have better spine control and can create a greater x-factor during the golf swing.

The purpose of this study was to investigate how the ball position along the mediolateral (M-L) direction of a golfer causes a chain effect in the ground reaction force, body segment and joint angles, and whole-body centre of mass during the golf swing. Twenty professional golfers were asked to complete five straight shots for each 5 different ball positions along M-L: 4.27 cm (ball diameter), 2.14 cm (ball radius), 0 cm (reference position at preferred ball position), - 2.14 cm, and - 4.27 cm, while their ground reaction force and body segment motions were captured. The dependant variables were calculated at 14 swing events from address to impact, and the differences between the ball positions were evaluated using Statistical Parametric Mapping. The left-sided ball positions at address showed a greater weight distribution on the left foot with a more open shoulder angle compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. These trends disappeared during the backswing and reappeared during the downswing. The whole-body centre of mass was also located towards the target for the left-sided ball positions throughout the golf swing compared to the reference ball position, whereas the trend was reversed for the right-sided ball positions. We have concluded that initial ball position at address can cause a series of chain effects throughout the golf swing.

There is a growing body of literature on strength and conditioning (S&C) interventions for golfers of various skill levels. The aim of this systematic review was to evaluate the effects of S&C interventions on measures of golf performance (clubhead speed, ball speed, distance, etc.). Three databases (PubMed, SPORTDiscus, Web of Science) were searched and twenty-five studies identified that evaluated the effects of a S&C intervention on at least one golf performance measure compared to a control or comparison group. Most studies used combinations of strength training, plyometrics, stretching or core exercise, with many finding a benefit. Though it varied across studies and outcomes, average increases in clubhead speed, ball speed and distance measures were 4-6.4% when significant findings were synthesized. Four studies also found significant changes to golf swing kinematics, while three others found positive effects on measures of accuracy or consistency. Future research should compare different S&C interventions, explore the role of training status, skill level and intervention duration on the effects of S&C interventions, and report individual responses in addition to group data. Further, research should continue to evaluate effects on swing kinematics, accuracy and direct golf performance measures (e.g., handicap index).

Motion capture data are widely used in different research fields such as medical, entertainment, and industry. However, most motion researches using motion capture data are carried out in the time-domain. To understand human motion complexities, it is necessary to analyze motion data in the frequency-domain. In this paper, to analyze human motions, we present a framework to transform motions into the instantaneous frequency-domain using the Hilbert-Huang transform (HHT). The empirical mode decomposition (EMD) that is a part of HHT decomposes nonstationary and nonlinear signals captured from the real-world experiments into pseudo monochromatic signals, so-called intrinsic mode function (IMF). Our research reveals that the multivariate EMD can decompose complicated human motions into a finite number of nonlinear modes (IMFs) corresponding to distinct motion primitives. Analyzing these decomposed motions in Hilbert spectrum, motion characteristics can be extracted and visualized in instantaneous frequency-domain. For example, we apply our framework to (1) a jump motion, (2) a foot-injured gait, and (3) a golf swing motion.

Music has been reported as a positive intervention for improving psychophysiological conditions and exercise performance. However, the effects of music intervention on golf performance in association with psychophysiological responses have not been well examined in the literature. The purpose of the study was to investigate the acute effects of self-selected music intervention on golf swing and putting performance, heart rate (HR), HR variability (HRV), and anxiety. Twenty collegiate golfers voluntarily participated in this study (age = 20.2 ± 1.4 years, height = 171.7 ± 8.0 cm, body weight = 69.5 ± 14.6 kg, golf experience = 7.5 ± 2.1 years). A cross-over and within-subject design was used in this study. Participants performed a non-music trial (T1), pre-exercise music trial (T2), and simultaneous music trial (T3) in a randomized order with 48-72 h apart. The participants were attached to a HR monitor to record the HR and HRV during the measurement. The golf swing and putting performance was assessed by using the Golfzon golf simulator system. The state-trait anxiety inventory-state questionnaire (STAI-S) was used to evaluate anxiety state. All measurements were taken during baseline (phase one) and after resting or music intervention (phase two). Repeated measurement of analysis of variance (ANOVA) and Cohen's effect size (ES) were used for statistical analyses. The results show no significant differences in golf swing and putting performance ( > 0.05). However, significant decrease in STAI-S score was found in T2 ( = 0.047, ES = 0.32). A significant increase in the standard deviation of normal R-R interval (SDNN), low-frequency power spectrum (LF), standard deviation of along the line-of-identity (SD2) in T2 and T3 were observed ( < 0.05). In conclusion, a single pre-exercise or simultaneous self-selected music intervention contributes minor effects to golf performance in collegiate golfers. The positive benefits of self-selected music intervention on the psychological condition and cardia-related modulation while practicing golf is warranted.

To determine the influence of tracking marker locations on wrist kinematics during free movements and the golf swing, with the intention of recommending a solution that generates meaningful three-dimensional wrist kinematics.

A 51-year-old man developed a sudden headache during golf practice, followed by a high fever. He was admitted with suspected neutrophilic meningitis and was diagnosed with chemical meningitis caused by a dermoid cyst rupture based on the characteristic magnetic resonance imaging (MRI) findings, which showed multiple lipid droplets in his ventricle and cistern. His repetitive golf-swing motion was suggested to be the cause of his dermoid cyst rupture. On MRI, the lipid droplets appeared to have migrated by gravity because of the body position. Therefore, the body position should be considered to prevent obstructive hydrocephalus by lipid droplets after a dermoid cyst rupture.

Golf swing segmentation with inertial measurement units (IMUs) is an essential process for swing analysis using wearables. However, no attempt has been made to apply machine learning models to estimate and divide golf swing phases. In this study, we proposed and verified two methods using machine learning models to segment the full golf swing into five major phases, including before and after the swing, from every single IMU attached to a body part. Proposed bidirectional long short-term memory-based and convolutional neural network-based methods rely on characteristics that automatically learn time-series features, including sequential body motion during a golf swing. Nine professional and eleven skilled male golfers participated in the experiment to collect swing data for training and verifying the methods. We verified the proposed methods using leave-one-out cross-validation. The results revealed average segmentation errors of 5-92 ms from each IMU attached to the head, wrist, and waist, accurate compared to the heuristic method in this study. In addition, both proposed methods could segment all the swing phases using only the acceleration data, bringing advantage in terms of power consumption. This implies that swing-segmentation methods using machine learning could be applied to various motion-analysis environments by dividing motion phases with less restriction on IMU placement.

This article details the development of adopting the Nesbit and McGinnis model of the golf swing as a starting point for studying golf performance optimization. The model was selected as it presents an opportunity to examine how non-naïve participants can learn and improve their swing mechanics, which could prove valuable in studying human learning in sports, rehabilitation, and re-education.

Full three-dimensional movements and external moments in golfers' knees and the possible involvement in injuries have not been evaluated using motion capture at high sample frequencies. This study measured joint angles and external moments around the three anatomical axes in both knees of 10 professional golfers performing golf drives whilst standing on two force plates in a motion capture laboratory. Significant differences were found in the knee joint moments between the lead and trail limbs for the peak values and throughout all stages during the swing phase. A significantly higher net abduction moment impulse was seen in the trail limb compared with the lead limb (-0.518 vs. -0.135 Nms.kg), indicating greater loading over the whole swing, which could contribute to knee lateral compartment or anterior cruciate ligament injuries. A significant correlation (= -0.85) between clubhead speed at ball contact and maximum joint moment was found, with the largest correlations being found for joint moments at the top of the backswing event and at the end of the follow-through. Therefore, although knee moments can contribute to high clubhead speeds, the large moments and impulses suggest that they may also contribute to chronic knee injuries or exacerbate existing conditions.

The biomechanics of a golf swing have been of interest to golfers, instructors, and biomechanists. In addition to the complexity of the three-dimensional (3D) dynamics of multi-segments of body, the closed-chain body posture as a result of both hands holding a club together makes it difficult to fully analyze the 3D kinetics of a golf swing. To identify the hand-grip joint force and torque applied by each hand, we directly measured the 3D internal grip force of nine registered professional golfers using an instrumented grip. A six-axis force-torque sensor was connected to a custom-made axially separated grip, which was then connected to a driver shaft using a manufactured screw thread. Subjects participated in two sessions of data collection featuring five driver swings with both a regular and customized sensor-embedded grip, respectively. Internal grip force measurement and upper limb kinematics were used to calculate the joint force and torque of the nine-linkage closed-chain of the upper limb and club using 3D inverse dynamics. Direct measurement of internal grip forces revealed a threefold greater right-hand torque application compared to the left hand, and counterforce by both hands was also found. The joint force and torque of the left arm tended to precede that of the right arm, the majority of which had peaks around the impact and showed a larger magnitude than that of the left arm. Due to the practical challenge of measuring internal force, heuristic estimation methods based on club kinematics showed fair approximation. Our results suggest that measuring the internal forces of the closed-chain posture could identify redundant joint kinetics and further propose a heuristic approximation.

During practice and competition, golfers are required to use submaximal effort to hit the ball a given distance, i.e., perform a partial shot. While the full golf swing has undergone extensive research, little has addressed partial shots and the biomechanical modifications golfers employ. This study investigates the biomechanical changes between full and partial swings, and determines if the partial swing is a scaled version of the full swing. Using a repeated measures design, 13 male golfers completed a minimum of 10 swings in the full and partial swing conditions, whilst club, ball, kinematic, and kinetic parameters were recorded. Large and statistically significant reductions in body motion (centre of pressure ellipse: 33.0%,  = 0.004,  = 2.26), combined with moderate reductions in lateral shift (25.5%,  = 0.004,  = 0.33) and smaller reductions in trunk rotation (arm to vertical at top of backswing: 14.1%,  = 0.002,  = 2.58) indicate golfers favour larger reductions in proximal measures, combined with diminished reductions as variables moved distally. Furthermore, the partial swing was not found to be a scaled version of the full swing implying a new approach to coaching practices might be considered.

Golf requires effective movement patterns to produce an effective swing and performance.

Golf is an international sport played by a variety of age groups and fitness levels, and although golf has a low to moderate aerobic intensity level, injuries are common among professional and amateur golfers. High amounts of force experienced during the golf swing can lead to injury when golfers lack appropriate strength or technique with the lower back most commonly injured. Research has indicated that trunk muscle activation, hip strength and mobility, and pelvis and trunk rotation are associated with low back pain (LBP). Based on anecdotal evidence, golf practitioners specifically address issues in weight shift, lumbar positioning, and pelvis sequencing for golfers with LBP. This review aims to elucidate the effects of proper and improper golf swing technique on LBP and to help golf practitioners understand how to approach the alleviation of LBP in their clientele.

Action observation elicits changes in primary motor cortex known as motor resonance, a phenomenon thought to underpin several functions, including our ability to understand and imitate others' actions. Motor resonance is modulated not only by the observer's motor expertise, but also their gaze behaviour. The aim of the present study was to investigate motor resonance and eye movements during observation of a dynamic goal-directed action, relative to an everyday one - a reach-grasp-lift (RGL) action, commonly used in action-observation-based neurorehabilitation protocols. Skilled and novice golfers watched videos of a golf swing and an RGL action as we recorded MEPs from three forearm muscles; gaze behaviour was concurrently monitored. Corticospinal excitability increased during golf swing observation, but it was not modulated by expertise, relative to baseline; no such changes were observed for the RGL task. MEP amplitudes were related to participants' gaze behaviour: in the RGL condition, target viewing was associated with lower MEP amplitudes; in the golf condition, MEP amplitudes were positively correlated with time spent looking at the effector or neighbouring regions. Viewing of a dynamic action such as the golf swing may enhance action observation treatment, especially when concurrent physical practice is not possible.

The golfer's body (trunk/arms/club) can be modeled as an inclined axle-chain system and the rotations of its parts observed on the functional swing plane (FSP) can represent the actual angular motions closely. The purpose of this study was to investigate the effects of pelvis-shoulders torsional separation style on the kinematic sequences employed by the axle-chain system in golf driving. Seventy-four male skilled golfers (handicap ≤ 3) were assigned to five groups based on their shoulder girdle motion and X-factor stretch characteristics: Late Shoulder Acceleration, Large Downswing Stretch, Large Backswing Stretch, Medium Total Stretch, and Small Total Stretch. Swing trials were captured by an optical system and the hip-line, thorax, shoulder-line, upper-lever, club, and wrist angular positions/velocities were calculated on the FSP. Kinematic sequences were established based on the timings of the peak angular velocities (backswing and downswing sequences) and the backswing-to-downswing transition time points (transition sequence). The backswing and transition sequences were somewhat consistent across the groups, showing full or partial proximal-to-distal sequences with minor variations. The downswing sequence was inconsistent across the groups and the angular velocity peaks of the body segments were not significantly separated. Various swing characteristics associated with the separation styles influenced the motion sequences.

We explored how practice and actual putting strokes differed between professionals and high-level golf amateurs, and how practice strokes reflected subtle differences in putting distances. We analysed swing amplitude, impact velocity, and acceleration profile of the club-head. The acceleration profiles showed that the motor control pattern of the practice stroke differed from that of the actual stroke. To clarify the effects of different putting distances on the practice stroke and to analyse how much the actual stroke could be explained by the practice stroke, we conducted individual regression analyses. The practice strokes of all participants could be divided into three strategies and five types by the coefficient of determination and the slope. This implies that the purpose of the practice stroke varied among golfers. Most golfers used the individual velocity criteria in their practice strokes, which resulted in different putting distances based on their criteria. Unexpectedly, we found no significant difference in skill level between professionals and high-level amateurs. The results of this study imply that the practice stroke does not duplicate the actual stroke, even for professional golfers with excellent skills. However, most high-level golfers adopted distance-dependent control strategies for slightly different putting distances.

The research aimed to evaluate the effects of an intervention aimed at altering pressure towards the medial aspect of the foot relating to stability mechanisms associated with the golf swing. We hypothesised that by altering the position of the foot pressure, the lower body stabilisation would improve which in turn would enhance weight distribution and underpinning lower body joint kinematics. Eight professional golf association (PGA) golf coaches performed five golf swings, recorded using a nine-camera motion analysis system synchronised with two force platforms. Following verbal intervention, they performed further five swings. One participant returned following a one-year intervention programme and performed five additional golf swings to provide a longitudinal case study analysis. Golf performance was unchanged evidenced by the velocity and angle of the club at ball impact (BI), although the one-year intervention significantly changed the percentage of weight experienced at each foot in the final 9% of downswing, which provided an even weight distribution at BI. This is a highly relevant finding as it indicates that the foot centre of pressure was central to the base of support and in-line with the centre of mass (CoM), indicating significantly increased stability when the CoM is near maximal acceleration.

Individuals have to reweight the respective contribution of the different sources of sensorial information for regulating posture and balance, especially during fine task execution. Given the evidences indicating strategy during swing performance as associated with prioritization of task-relevant visuospatial information for skill execution, the aim of the present work is to assess differences in visual dependency (VD) and postural control in a population of expert (EXP) and non-expert (NEXP) golfers when compared with healthy subjects (HC) and to discover possible relationships between these outcomes and swing performance. Thus, 15 golfers (EXP = 7; NEXP = 8) and 32 matched HC underwent otoneurological testing including video Head Impulse Test, posturography and Rod and Disk Test (RDT). Golf players also underwent a swing session procedure, which performance was measured by means of the Flightscope X2 Doppler-radar launch monitor system. EXP subjects demonstrated significant ( < 0.05) lower values in i) counter-clockwise (CCW) and clockwise (CW) dynamic conditions when compared with both NEXP and HC subjects RDT outcome measures and ii) surface and length posturography values as compared with HC subjects. When treating golf players outcomes as 'a continuum', CCW and CW scores were found to positively correlate with both lateral distance and horizontal launch angle and to negatively correlate with spin rpm. In conclusion, the present study suggests that the high-level of visual-independency demonstrated by EXP subjects may be functionally related in expert golfers to an effective motor strategy preferentially not referring to an inappropriate reliance on visual input.

The current study aims to compare the variability of positional control of the club in the starting period of downswing and the orientation of the clubface during impact in elite and intermediate golfers.

In golf, the trunk and pelvis kinematic variables are often related to measures of performance due to the highly complex and multi-joint movements involved in swings. However, it is unclear how specific body segments or joints contributed to the golf performance parameters. Therefore, the purpose of this study was to identify the key joints, including those of the upper and lower trunk, that are associated with golf performance parameters, such as X-Factor and pelvis motion. A motion capture system was used to obtain three-dimensional kinematics of golf swings performed by 10 low handicap male golfers. Based on regression analysis, right knee adduction, right shoulder external rotation and left elbow extension in ball address to top of the backswing and left knee adduction and lower trunk right bending with left rotation in top of the backswing to end of follow-through were presented as predictor variables for the X-Factor. For pelvis movement, a greater number of joint angles were associated with pelvis posterior tilt during backswing and pelvis motion to target with right rotation during downswing/follow-through. This study provides fundamental details of the movement mechanisms of major joints, as well as their relationships with performance parameters. Such understanding can be combined with training to improve the golfing skill and prevent possible injuries.

The purposes of this study were to characterise the golfer-ground interactions during the swing and to identify meaningful associations between the golfer-ground interaction force/moment parameters and the maximum clubhead speed in 63 highly skilled male golfers (handicap ≤ 3). Golfers performed shots in 3 club conditions (driver, 5-iron and pitching wedge) which were captured by an optical motion capture system and 2 force plates. In addition to the ground reaction forces (GRFs), 3 different golfer-ground interaction moments (GRF moments, pivoting moments and foot contact moments) were computed. The GRF moment about the forward/backward (F/B) axis and the pivoting moment about the vertical axis were identified as the primary moments. Significant (p < 0.05) correlations of peak force parameters (all components in the lead foot and F/B component in the trail foot) and peak moment parameters (lead-foot GRF moment and trail-foot pivoting moment) to clubhead speed were found. The lead-foot was responsible for generating the GRF moment, while the trail foot contributed to the pivoting moment more. The instant the lead arm becomes parallel to the ground was identified as the point of maximum angular effort, and the loading onto the lead-foot near this point was critical in generating both peak moments.

Wrist movements have been identified as an important factor in producing a successful golf swing, with their complex motion influencing both club head velocity and orientation. However, a detailed analysis of wrist angles is lacking in the literature. The purpose of this study was to determine kinematics across wrists and club head characteristics during the golf swing under weak, neutral and strong grip conditions. Twelve professional male golfers executed 24 shots using a driver under three grip conditions. A six degrees of freedom analysis of the hand with respect to the distal forearm was performed using a 10-camera three-dimensional motion capture system. Differences in joint angles were explored using repeated measures ANOVAs at key swing events (onset, top of backswing and impact), in addition club head velocity and clubface angle at impact were also explored. Main findings revealed significant differences in flexion/extension and internal/external rotation for both wrists at all swing events, whereas fewer significant interactions were found in ulnar/radial deviation across grips for both wrists at all events. Clubface angle only differed significantly between the weak and the strong and neural grips, presenting a more 'open' clubface to the intended hitting direction. This study is the first to explore tri-planar wrist movement and the effect of different grips, such analysis has implications for coaching knowledge and practice and should inform future research into different aspects of skill, technique analysis and may inform injury mechanisms/prevention.

Previous research has highlighted the positive effect that different warm-up protocols have on golf performance (e.g. Sorbie et al., 2016; Tilley & Macfarlane, 2012) with the design of warm-ups and programmes targeting and improving golf performance through the activation and development of specific muscle groups. This study aimed to examine the acute effects of two warm-up protocols on golf drive performance in comparison to a control condition. Using a randomised counterbalanced design over three testing sessions, twenty-three highly skilled golfers completed the control, dynamic and resistance-band warm-up conditions. Following each condition, a GC2 launch monitor was used to record ball velocity and other launch parameters of ten shots hit with the participants' own driver. A repeated-measures ANOVA found significant increases in ball velocity (η = .217) between the control and both the dynamic and resistance-band warm-up conditions but no difference between these latter two, and a reduction in launch angle between control and dynamic conditions. The use of either a dynamic stretching or resistance-band warm-up can have acute benefits on ball velocity but golfers should liaise with a PGA Professional golf coach to effectively integrate this into their golf driving performance.

The aim of this study was to perform the static and dynamic biomechanical assessment of postural structure and analyze variations of foot pressure in elite golfers.

Golf shots off uneven terrain often require modifications in address position to complete the swing successfully. This study aimed to determine how golf players coordinate the legs to regulate linear and angular impulse (about an axis passing vertically through the center of mass) while modifying the lower extremity address position during the swing. Nine highly skilled golf players performed swings with a 6-iron under the Normal, Rear Leg Up and Target Leg Up conditions. Components of linear and angular impulse generated by the rear and target legs (resultant horizontal reaction force, resultant horizontal reaction force angle, and moment arm) were quantified and compared across the group and within a player (α = .05). Net angular impulse did not change between conditions. Target leg angular impulse was greater in the Target Leg Up condition than Rear Leg Up condition. Regulation of linear and angular impulse generation occurred while increasing stance width and redirecting resultant horizontal reaction forces to be more parallel to the target line under modified address positions. Net linear impulse perpendicular to the target was near zero or slightly posterior. Net linear impulse parallel to the target was less toward the target in the Target Leg Up condition compared to Normal and Rear Leg Up conditions. These results indicate individuals utilized player specific mechanisms to coordinate the legs and regulate impulse generation during the golf swing under modified address positions.

Although many studies on choking under pressure used closed skills, such as golf putting, we examined the influence of pressure on movement during a dynamic skill by studying participants' kinematic and kinetic changes during a table tennis forehand task under pressure. Thirty novice table tennis players hit forehand shots toward a target for 135 practice trials and then performed 10 no-pressure and 10 pressure trials. We added psychological pressure by instructing participants they could earn monetary rewards for successful performance and by cancelling accumulated scores for a poor performance. We measured racket head and ball movements as kinematic variables and grip force as a kinetic variable. We also measured state anxiety and heart rate as checks on our manipulation of psychological pressure. In the pressure condition, both state anxiety and heart rate increased significantly ( p < .025), though the pressure level was relatively small. Analysis of kinematic measures revealed that back swing and forward swing were reduced in length; speed of forward swing and ball speed decreased significantly ( p < .008) under pressure. Also, under pressure, ball and racket contact point shifted forward significantly ( p < .008) to reduce the distance between impact and target locations, and performance declined as the ball-landing locations shifted leftward ( p < .007). Grip force showed no significant change. We conclude that, under pressure, movement was modified toward reduced displacement and lower speed in an apparent risk-aversive hitting strategy; these modifications resulted in a performance decrement.

A study was conducted to investigate the underlying mechanisms involved in the dynamics of body motions during the golf swing. A series of model simulation programs were developed in OpenSim to control the characteristics of the biomechanical model of the body. The resultant model parameters were put in an Excel file, which allowed these parameters to be modified. OpenSim model simulation run was paused at various points of the golf swing and screenshots were taken. MATLAB was used to find the positional value of the center of clubface for each screenshot and the Euclidean distances of the clubhead position between poses. A series of simulation trials were then conducted using various time increments between the poses in order to calculate the clubhead velocities. Three of these trials were selected to illustrate the swing patterns of players of varying skill levels ranging from basic beginner to highly-skilled. These simulations using OpenSim can serve as a platform for understanding the dynamics of body motions in sports and biomedicine.

This study investigated the relationship between a range of neuromechanical variables in the lower- and upper-body, and golf performance. Participants were assessed for individual muscle stiffness, vertical stiffness (Kvert), flexibility, power and maximal isometric strength. Furthermore, golf performance was determined by handicap and club head speed. Pearson's correlations quantified the relationships between neuromechanical variables and performance measures. Participants were also separated into relatively high club head speed (HC) and low club head speed (LC) groups and compared for physical characteristics. Club head speed showed positive relationships with Kvert and power and a negative relationship with hip mobility. The HC group exhibited superior Kvert and power, while strength and flexibility measures were not related to performance. Higher levels of lower-body stiffness, rate of force development and power output appear to be beneficial for generating superior club head speed. A stiffer system may reduce the time needed to remove the "slack" from the series elastic component therefore, reducing electromechanical delay and enhancing rate of force development. The positive association with rate of force development suggests that increasing this component, along with power production may be superior focal components for training in golfers due to the short duration of the downswing.

The purpose of this study was to investigate address position variables in response to changes in ball position in golfers. Eleven male professional golfers were instructed to perform their golf swing. A three-dimensional motion analysis system, with eight infrared cameras and two force platforms, was used to capture the address positions. A golf ball has a diameter of 4.27 cm, and a radius of 2.14 cm. Even small movements of ball position in the mediolateral (M-L) and anteroposterior (A-P) directions significantly changed the address position. When the ball was moved to the left, the shoulder rotation and club-face aim rotated toward the left of the target, and the left vertical ground reaction force increased. When the ball was moved to the right, the opposite findings were observed. When the ball was moved closer, the trunk, hip, knee, ankle, and absolute arm angle extended; the lie angle of the golf club increased; and the center of pressure moved toward the posterior direction. These changes were reversed when the ball was moved further away. The M-L ball position critically changed the address positions of the upper extremities in the horizontal plane, and the A-P ball position critically changed the angles of whole body parts in the sagittal plane. Furthermore, club-head kinematics at impact such as club-face aim, club path, and angle of attack were significantly changed in the M-L ball position; and club-head speed and angle of attack were significantly changed in the A-P ball position. This in-depth understanding of the address position in association with the ball position could provide valuable data for swing coaches when finding a golfer's optimal address position.

Golf is a common recreational and competitive sport that requires full hip rotation to allow for a smooth and effective swing. Therefore hip impingement and hip osteoarthritis, by limiting rotation, could cause pain in golfers and even encourage them to discontinue the sport. In my opinion, the lead hip in golfers is likely what generally drives the symptoms in the hip, back, or knee. After surgical correction, golfers are able to get back to golf and many experience improved performance.

In the sport of golf, there is no standard teaching method or swing technique even though golf is known for overuse injuries. This prospective study was to analyze classic swing kinematics in comparison with the Free-Release method and to define a physiological golf swing. Two hundred eighty-three players, age 50-59 years, were included in the study. For both swing techniques, examination addressed swing visualization, center of pressure (COP), center of mass (COM), as well as pelvic movement in relationship to different standing widths. The position of the spine was evaluated in the frontal and lateral planes. Using the classic technique, no golfer was able to describe his swing parameters, which would be necessary for visualization and to tolerate physiological range of movement, whereas players using the Free-Release method were able to provide such a description. COP and COM showed pathological swing mechanics for the classic technique, whereas for the Free-Release method mechanics were physiological. We conclude that to prevent lumbar spine injury, the classic swinging technique, which is characterized by lateral shear forces, static and dynamic pelvic side bending while rotating with high force against the spine, and an unbalanced COM and COP, should be substituted by the Free-Release technique as a new physiological guideline.

Pelvis-thorax coordination has been recognised to be associated with swing speed. Increasing angular separation between the pelvis and thorax has been thought to initiate the stretch shortening cycle and lead to increased clubhead speed. The purpose of this study was to determine whether pelvis-thorax coupling played a significant role in regulating clubhead speed, in a group of low-handicap golfers (mean handicap = 4.1). Sixteen participants played shots to target distances determined based on their typical 5- and 6-iron shot distances. Half the difference between median 5- and 6-iron distance for each participant was used to create three swing effort conditions: "minus", "norm", and "plus". Ten shots were played under each swing effort condition using both the 5-iron and 6-iron, resulting in six shot categories and 60 shots per participant. No significant differences were found for X-factor for club or swing effort. X-factor stretch showed significant differences for club and swing effort. Continuous relative phase (CRP) results mainly showed evidence of the stretch shortening cycle in the downswing and that it was more pronounced late in the downswing as swing effort increased. Substantial inter-individual CRP variability demonstrated the need for individual analyses when investigating coordination in the golf swing.

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.

Numerous skill batteries assess fundamental motor skill (e.g., kick, hop) competence. Few skill batteries examine lifelong physical activity skill competence (e.g., resistance training). This study aimed to develop and assess the content validity, test-retest and inter-rater reliability of the "Lifelong Physical Activity Skills Battery". Development of the skill battery occurred in three stages: i) systematic reviews of lifelong physical activity participation rates and existing motor skill assessment tools, ii) practitioner consultation and iii) research expert consultation. The final battery included eight skills: grapevine, golf swing, jog, push-up, squat, tennis forehand, upward dog and warrior I. Adolescents (28 boys, 29 girls; M = 15.8 years, SD = 0.4 years) completed the Lifelong Physical Activity Skills Battery on two occasions two weeks apart. The skill battery was highly reliable (ICC = 0.84, 95% CI = 0.72-0.90) with individual skill reliability scores ranging from moderate (warrior I; ICC = 0.56) to high (tennis forehand; ICC = 0.82). Typical error (4.0; 95% CI 3.4-5.0) and proportional bias (r = -0.21, p = .323) were low. This study has provided preliminary evidence for the content validity and reliability of the Lifelong Physical Activity Skills Battery in an adolescent population.

To evaluate if shoulder and pelvic angular velocities differ at impact or peak magnitude between professional and amateur golfers. Golf swing rotational biomechanics are a key determinant of power generation, driving distance, and injury prevention. We hypothesize that shoulder and pelvic angular velocities would be highly consistent in professionals.

The aim of the study was to examine changes in weight transfer, alignment, and shot outcome during golf shots from flat, uphill, and downhill slopes. Twelve elite male golfers hit 30 shots with a 6-iron from a computer-assisted rehabilitation environment used to create 5° slopes while collecting 3-dimensional kinematics and kinetics of the swing. A launch monitor measured performance outcomes. A shift in the center of pressure was found throughout the swing when performed on a slope, with the mean position moving approximately 9% closer to the lower foot. The golfers attempted to remain perpendicular to the slope, resulting in weight transfer toward the lower foot. The golfers adopted a wider stance in the sloped conditions and moved the ball toward the higher foot at address. Ball speed was not significantly affected by the slope, but launch angle and ball spin were. As the coaching literature predicted, golfers were more likely to hit shots to the left from an uphill slope and to the right from a downhill slope. No consistent compensatory adjustments in alignment at address or azimuth were found, with the change in final shot dispersion resulting from the lateral spin of the ball.

This study aims to analyze the incidence, location, type, and mechanisms of injuries and possible injury risk factors among all levels of Korean female professional golfers. This was a prospective study with a follow-up period of 24 months. A total of 363 members of the Korean Ladies Professional Golf Association (KLPGA), who competed in tournaments during the 2015 and 2016 seasons, took part in the study. The incidence of injury varied by tournament level and was significantly higher in Division II (11.1/1000AEs) and Division III (13.4/1000AEs) than in Division I (5.6/1000AEs) (p < 0.05). The most common location and type of injury were the shoulder/clavicle (Division I: 14.1%, Division II: 15.7%, Division III: 17.3%) and the tendinosis or tendinopathy (21.2%) (Division I: 23.7%, Division II: 21.2%, Division III: 18.5%), respectively. The most common mechanism of injury was the golf swing (47.9%-51.6% for the three divisions), and the most frequent specific phase of injury was upon ball impact (23.5%-30.9%). Multivariate analysis revealed that body mass index and the number of previous season competitions were significantly associated with injury risk in female golfers. The other factors examined did not have a significant association with golf-related injuries. In conclusion, KLPGA golfers were commonly exposed to injuries and showed a higher rate of injuries in competitions than practices, with significantly higher in Division II, III than Division I. However, overall, there was no significant difference in the location, type, mechanism and risk factors for injuries among the division level of KLPGA.

This study aimed to understand how players coordinate the multi-joint control strategies of the rear and target legs to satisfy the lower extremity and whole-body mechanical objectives during the golf swing when hitting shots with different clubs. Highly skilled golf players (n = 10) performed golf swings with a 6-iron and a driver. Joint kinetics were calculated using ground reaction forces and segment kinematics to determine net joint moments (NJMs) during the interval of interest within the downswing. Between club difference in NJMs and 3D support moments were compared across the group and within a player. Although player-specific multi-joint control strategies arose, players generally increased target leg ankle, knee, and hip NJMs when hitting with the driver while maintaining the relative contribution to the 3D support moment. Multi-joint control strategies used to control the target and rear legs were found to be different, yet the majority of the 3D support moment was produced by NJMs about an axis perpendicular to the leg planes. These results emphasize the importance of recognizing how an individual player coordinates multi-joint control from each leg, and highlights the need to design interventions that are player and leg specific to aid in improving player performance.

The knee joint is one of the most frequently injured regions in the game of golf, and the loads experienced by the knee during the golf swing are typically greater than during other activities of daily living. Altering movement patterns is a common strategy that can be used to reduce loading on the knee joint but has received little attention during studies of the golf swing. The primary aim of this study was to examine the effect altering golf stance has on the lead limb peak external knee adduction moment.

The golf swing is a complex full body movement during which the spine and shoulders are highly involved. In order to determine shoulder kinematics during this movement, multibody kinematics optimization (MKO) can be recommended to limit the effect of the soft tissue artifact and to avoid joint dislocations or bone penetration in reconstructed kinematics. Classically, in golf biomechanics research, the shoulder is represented by a 3 degrees-of-freedom model representing the glenohumeral joint. More complex and physiological models are already provided in the scientific literature. Particularly, the model used in this study was a full body model and also described motions of clavicles and scapulae. This study aimed at quantifying the effect of utilizing a more complex and physiological shoulder model when studying the golf swing. Results obtained on 20 golfers showed that a more complex and physiologically-accurate model can more efficiently track experimental markers, which resulted in differences in joint kinematics. Hence, the model with 3 degrees-of-freedom between the humerus and the thorax may be inadequate when combined with MKO and a more physiological model would be beneficial. Finally, results would also be improved through a subject-specific approach for the determination of the segment lengths.

In putting, golfers require an internal forward sense of the causal relationship between putting actions and outcomes-a sense of distance-to decide appropriate impact intensity. As no previous work has shown such a cognitive ability in skilled golfers, we sought to quantify sense-of-distance skill differences between experts and novice golfers in both putting-swing consistency and accuracy of outcome estimation. We compared nine expert and nine novice golfers on putting-outcome estimation by having them putt a golf ball to a target located at three distances (1.2, 2.4, and 3.6 m), and then, after automatic closure of their electric-shutter spectacles immediately following putter impact with the ball, they gave their best estimate of where the ball stopped. We assessed outcome-estimation accuracy by calculating the absolute error between the stopped ball's actual and estimated positions. We also measured and analyzed putter head-swing movements during the task using a motion-capture system. Two-way, mixed-design analysis of variance tests revealed that expert golfers achieved both significantly lower variability in putter-head kinematics and higher accuracy at outcome estimation than the novices. Linear partial correlation analyses with target distance as the control variable tested the relationship between outcome-estimation performance and putter-head variability kinematic measurements. There were no significant correlations between them for experts and novices in separate databases, while medium correlations were found in a collective database. Thus, swing consistency and a sense of distance are independent skills that both account for putting expertise, and specific training is required for each to improve putting skills.

Increasing numbers of people are playing golf. Golf is a unique sport in that the ability to participate at a high level is not limited by age. In addition, participants tend to play more rather than less as they grow older. Injuries can occur at any point during the golf swing, from takeaway through follow-through. Upper extremity injuries can affect the hands, elbow, and shoulder and are usually a result of the golf swing at impact. Injuries are also common in the lower back as well as the lower extremities. Most injuries are the result of overuse and poor swing mechanics. When treating golfers, it is important to have a good understanding of the biomechanics and forces of the golf swing to diagnose and manage the vast spectrum of injuries incurred in this sport.

Golf is commonly considered a low-impact sport that carries little risk of injury to the knee and is generally allowed following total knee arthroplasty (TKA). Kinematic and kinetic studies of the golf swing have reported results relevant to the knee, but consensus as to the loads experienced during a swing and how the biomechanics of an individual's technique may expose the knee to risk of injury is lacking.

Golfers with disability are limited in the execution of the full golf swing, but their performance in putting may be comparable because this stroke does not demand significant strength, balance and range of motion. Therefore, the aim of this study was to compare putting performance, kinetic and kinematic consistency between golfers with different disabilities and healthy athletes. The participants consisted of three disabled athletes (perinatal cerebral palsy, multiple sclerosis, below knee lower limb amputee) and three healthy golfers (age 34 ± 4.5 years, body height 178 ± 3.3 cm, body mass 83 ± 6.2 kg). The golfers' movements were recorded by active 3D markers for kinematic analyses; the subjects performed 10 trials of a 6 m putting task while standing on separate force platforms placed under each lower limb. Putting performance was measured by the distance of the final ball position to the centre of the hole. ANOVA analyses did not show any differences in clubhead speed and total ball distance from the hole. The consistency of those two parameters expressed by the coefficient of variation (CV) was CV = 0.5% or better in both groups for clubhead speed and ranged from CV = 0.40 to 0.61% in healthy and CV = 0.21 to 0.55% in disabled athletes for total error distance. The main effect ANOVA showed differences in weight shift, hip and shoulder kinematics (p < 0.05) between healthy players and all players with disability. All disabled athletes shifted their weight toward the healthy side (towards the healthy lower limb) and alternated the end of the swing. The player with below knee amputation had the lowest range of motion in the shoulder joint during the putting stroke. The players with perinatal cerebral palsy and multiple sclerosis had the largest range of motion in the hips. Putting performance of disabled golfers was similar to healthy athletes. During training of disabled players, coaches should pay attention to the specificity of a particular disability when focused on putting performance. However, individual technique should achieve the same consistency as observed in healthy players.

This study aimed to evaluate movement acceleration characteristics in adolescents with Down syndrome (DS) and typical development (TD), while playing bowling and golf videogames on the Nintendo Wii™.

We report the rare case of a patient presenting with a spontaneous laceration of left internal mammary artery (LIMA) after playing golf. The patient had no specific history except for cardiac surgery, and there were no results that caused bleeding on preoperative examination. A computed tomography (CT) scan of the chest demonstrated an anterior mediastinal hematoma and a left hemothorax with active extravasation close to LIMA. Through thoracotomy, hematoma evacuation and clipping for lacerated artery were performed. The patient was discharged in stable condition on the sixteenth postoperative day. This is the first reported case of a spontaneous laceration of internal mammary artery (IMA) after playing golf.

[Purpose] In sports physical therapy, video of a patient's movement or of a skilled model's movement has been used as observational learning methods for injury prevention and movement modification. Positive effects of model video observation have been reported. This study aimed to clarify the effect on motor skill learning using a combination of model-observation and self-observation, which is thought to act as an enhanced method for active error detection by comparing model-observation and self-observation alone for acquisition of correct sports movement. [Subjects and Methods] Forty-five healthy females were randomly allocated into three groups comprising model- and self-observation, model-observation, and self-observation. The motor task performed was a half golf swing using an elastic club. Shoulder grip angle between both shoulder lines and the acromia grip strength were measured as an index of body rotation using a three-dimensional motion analyzer. Change in the shoulder grip angle in the three groups was analyzed at pre-, immediate delayed retention, and delayed retention tests. [Results] A significant difference in shoulder grip angle was observed among the three groups for the immediate delayed retention test. The combined model and self-observation group had a value closer to 90 degrees compared to the other two groups. [Conclusion] Observation combining model and self-observation exerted a positive effect on short-term motor skill learning.

Cascade tripping of power lines triggered by maloperation of zone-3 relays during stressed system conditions, such as load encroachment, power swing and voltage instability, has led to many catastrophic power failures worldwide, including Indian blackouts in 2012. With the introduction of wide-area measurement systems (WAMS) into the grids, real-time monitoring of transmission network condition is possible. A phasor measurement unit (PMU) sends time-synchronized data to a phasor data concentrator, which can provide a control signal to substation devices. The latency associated with the communication system makes WAMS suitable for a slower form of protection. In this work, a method to identify the faulted line using synchronized data from strategic PMU locations is proposed. Subsequently, a supervisory signal is generated for specific relays in the system for any disturbance or stressed condition. For a given system, an approach to decide the strategic locations for PMU placement is developed, which can be used for determining the minimum number of PMUs required for application of the method. The accuracy of the scheme is tested for faults during normal and stressed conditions in a New England 39-bus system simulated using EMTDC/PSCAD software. With such a strategy, maloperation of relays can be averted in many situations and thereby blackouts/large-scale disturbances can be prevented.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'.

Golf is a popular sport among patients undergoing total knee arthroplasty (TKA). The golf swing requires significant knee rotation, which may lead to changes in golfing ability postoperatively. The type of implant used may alter the swing mechanics or place different stresses on the knee. The purpose of this study was to evaluate golf performance and subjective stability after TKA and compare outcomes between cruciate-retaining (CR) and posterior-stabilized (PS) implants.

Good balance, flexibility, and strength are all required to maintain a steady stance during the kinematic chain to produce successful golf shots. When the body can produce more power, more club head speed is generated. This formation of power translates into greater distance and accuracy. Athletes today are seeking exercise programs to enhance these qualities of their golf swing. The purpose of this study is to investigate the correlations between flexibility and balance with club head speed and driving distance in the golf swing of male and female collegiate golfers. Five male and five female collegiate golfers participated in the study. They completed multiple range of motion tests, the Balance Error System Test, and multiple flexibility tests. Subjects then participated in a short hitting session. Ten shots were hit with the subject's own driver. The Optishot simulator measured distance and club head speed generated. There was a significant negative correlation between the BESS test score and average distance for male subjects (r=-0.850, p=0.034). There were also a few trends between the balance, flexibility, and club head speed findings of both male and female subjects. This data shows there is a significant relationship between better balance and driving the ball farther. Other trends show better balance and flexibility will result in greater driving distance and club head speed. Balance and flexibility exercises should be incorporated into a golfer's practice or workout regiment.

It has previously been shown that isotonic strength training can improve driver performance among golfers, though few studies have investigated effects of strength training on swing kinematics together with driver performance. In this study we investigated whether isokinetic rotational training could improve driver performance and swing kinematic variables amongst elite golfers.

The purpose of this study was to assess the effects of three different programs, i.e. active dynamic warm-up program plus functional resistance warm-up using Theraband plus pre-shot routine program (AFPR); pre-shot routine program (PR); and active dynamic warm-up program plus functional resistance warm-up using Theraband (AF) on driver club head speed, driving distance, and driving accuracy in the amateur golfers. Fifteen amateur golfers with an average age of 19.67 ± 0.89 years and 4.87 ± 1.77 points of average handicap were assigned to participate in either AFPR, PR or AF program. All participants in the three programs practiced three sessions on non-consecutive days per week during the intervention phase. Each participant's performance was assessed before and after six weeks of the program through hitting ten maximal drives with the ball flight and swing analyzed using the P3ProSwing Golf Simulator and recorded for the driver club head speed, driving distance, and driving accuracy. Multivariate analysis of variance showed no statistically significant differences (P < .05) of the performances of the golfers participated in the 3 programs (club head speed: F = 1.02, P = 0.33; accuracy: F = 0.32, P = 0.72; distance: F = 0.18, P = 0.83). Furthermore, a paired t-tests also showed no statistically significant (P < .05) improvement occurred in the 3 programs after the six-week training. Although the effect of the 3 programs did not show statistically significant increase in the performance of the amateur golfers, however, the three parameters of the performance, i.e. the driver club head speed, the driving distance and the driving accuracy showed certain improvements. The 3 training programs may have benefit to the amateur golfers with certain increases of their performance.

Low back pain is common in golfers. The risk factors for golf-related low back pain are unclear but may include individual demographic, anthropometric, and practice factors as well as movement characteristics of the golf swing.

The golf swing is a complex whole-body motion for which a proximal-to-distal transfer of the segmental angular velocities from the pelvis to the club is believed to be optimal for maximizing the club head linear velocity. However, previous experimental results about such timing (or kinematic sequence) are contradictory. Nevertheless, methods that were used in these studies differed significantly, in particular, those regarding the component of the angular velocity vector selected for the identification of the kinematic sequence. Hence, the aim of this study was to investigate the effect of angular velocity vector component selection on the identified kinematic sequence.

Due to the early specialization of golf players, examining the within session sequence of training should be considered to enhance performance and prevent injury risk. The present study analyzed the effects of an 18-week concurrent training developed before or after a specific golf session in adolescence elite golfers on several performance factors.

In recent years, significant advances in the development of computer vision technology have produced many platforms and systems that combine computer technology and sports-assisted training, including intelligent systems that are integrated with golf training and instruction. However, the existing intelligent systems for golf-assisted teaching usually use three-dimensional depth information, which will significantly increase the cost of intelligent systems. In this paper, the extraction of golf club slope is carried out on the basis of golf sport video capture using a common monocular camera in order to match the club slope information with the professional coach swing video information. At the same time, in order to facilitate the interframe matching, the joint point information is complemented using the projection approximation point algorithm, and the segmentation of the swing video is performed using the complemented human hand joints and the fixed characteristics of the golf swing. Then, in order to solve the problem that human joints will have the same joint angle under different movements, the human limb joint angles are defined and then the swing movements in the user video frames are evaluated.