Acute and persistence of the effects of the SuperSpeed Golf™ weighted-club warm-up on golf driving performance and kinematics

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 d ≥ small) and significant (p≤ 0.05) effect detected in the first set was investigated in subsequent sets. SuperSpeed led to small 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 large negative change in smash factor acutely (d - 0.82, p= 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.

Enhancing accuracy and convenience of golf swing tracking with a wrist-worn single inertial sensor

In this study, we address two technical challenges to enhance golf swing trajectory accuracy using a wrist-worn inertial sensor: orientation estimation and drift error mitigation. We extrapolated consistent sensor orientation from specific address-phase signal segments and trained the estimation with a convolutional neural network. We then mitigated drift error by applying a constraint on wrist speed at the address, backswing top, and finish, and ensuring that the wrist's finish displacement aligns with a virtual circle on the 3D swing plane. To verify the proposed methods, we gathered data from twenty male right-handed golfers, including professionals and amateurs, using a driver and a 7-iron. The orientation estimation error was about 60% of the baseline, comparable to studies requiring additional sensor information or calibration poses. The drift error was halved and the single-inertial-sensor tracking performance across all swing phases was about 17 cm, on par with multimodal approaches. This study introduces a novel signal processing method for tracking rapid, wide-ranging motions, such as a golf swing, while maintaining user convenience. Our results could impact the burgeoning field of daily motion monitoring for health care, especially with the increasing prevalence of wearable devices like smartwatches.

Kinematic, Kinetic, and Temporal Metrics Associated With Golf Proficiency

ABSTRACT

McHugh, MP, O'Mahoney, CA, Orishimo, KF, Kremenic, IJ, and Nicholas, SJ. Kinematic, kinetic, and temporal metrics associated with golf proficiency. J Strength Cond Res 38(3): 599-606, 2024-The biomechanics of the golf swing have been studied extensively, but the literature is unclear on which metrics are indicative of proficiency. The purpose of this study was to determine which metrics identified golf proficiency. It was hypothesized that discrete kinematic, kinetic, and temporal metrics would vary depending on proficiency and that combinations of metrics from each category would explain specific proficiency metrics. Kinematic, kinetic, and temporal metrics and their sequencing were collected for shots performed with a driver in 33 male golfers categorized as proficient, average, or unskilled (based on a combination of handicap, ball velocity, and driving distance). Kinematic data were collected with high-speed motion analysis, and ground reaction forces (GRF) were collected from dual force plates. Proficient golfers had greater x-factor at ball impact and greater trunk deceleration before ball impact compared with average ( p < 0.05) and unskilled ( p < 0.01) golfers. Unskilled golfers had lower x-factor at the top of the back swing and lower peak x-factor, and they took longer to reach peak trunk velocity and peak lead foot GRF compared with average ( p < 0.05) and proficient ( p < 0.05) golfers. A combination of 2 kinematic metrics (x-factor at ball impact and peak pelvis velocity), 1 kinetic metric (peak lead foot GRF), and 2 timing metrics (the timing of peak trunk and arm velocity) explained 85% of the variability in ball velocity. The finding that x-factor at ball impact and trunk deceleration identified golf proficiency points to the potential for axial trunk rotation training to improve performance.

Validation of Inertial Measurement Units for Analyzing Golf Swing Rotational Biomechanics

Training devices to enhance golf swing technique are increasingly in demand. Golf swing biomechanics are typically assessed in a laboratory setting and not readily accessible. Inertial measurement units (IMUs) offer improved access as they are wearable, cost-effective, and user-friendly. This study investigates the accuracy of IMU-based golf swing kinematics of upper torso and pelvic rotation compared to lab-based 3D motion capture. Thirty-six male and female professional and amateur golfers participated in the study, nine in each sub-group. Golf swing rotational kinematics, including upper torso and pelvic rotation, pelvic rotational velocity, S-factor (shoulder obliquity), O-factor (pelvic obliquity), and X-factor were compared. Strong positive correlations between IMU and 3D motion capture were found for all parameters; Intraclass Correlations ranged from 0.91 (95% confidence interval [CI]: 0.89, 0.93) for O-factor to 1.00 (95% CI: 1.00, 1.00) for upper torso rotation; Pearson coefficients ranged from 0.92 (95% CI: 0.92, 0.93) for O-factor to 1.00 (95% CI: 1.00, 1.00) for upper torso rotation (p < 0.001 for all). Bland-Altman analysis demonstrated good agreement between the two methods; absolute mean differences ranged from 0.61 to 1.67 degrees. Results suggest that IMUs provide a practical and viable alternative for golf swing analysis, offering golfers accessible and wearable biomechanical feedback to enhance performance. Furthermore, integrating IMUs into golf coaching can advance swing analysis and personalized training protocols. In conclusion, IMUs show significant promise as cost-effective and practical devices for golf swing analysis, benefiting golfers across all skill levels and providing benchmarks for training.

Lower Limb Biomechanics during the Golf Downswing in Individuals with and without a History of Knee Joint Injury

Although prevention is better than treatment, after a knee injury occurs, the adjustment of the movement technique back to the posture before the injury and the restoration of accuracy is very important for professional and amateur players. This study aimed to compare the differences in lower limb mechanics during the golf downswing between those with and without a history of knee joint injury. A total of 20 professional golfers with single-digit handicaps were recruited for this study, 10 of whom had a knee injury history (KIH+), while another 10 players were without a knee injury history (KIH-). From the 3D analysis, selected kinematic and kinetic parameters during the downswing were analyzed using an independent samples t-test with a significance level of α = 0.05. During the downswing, individuals with KIH+ exhibited a smaller hip flexion angle, smaller ankle abduction angle, and larger ankle adduction/abduction range of motion (ROM). Moreover, there was no significant difference found in the knee joint moment. Athletes with a history of knee injury can adjust the motion angles of their hip and ankle joints (e.g., by avoiding excessive forward leaning of the trunk and maintaining stable foot posture without inward or outward rotation) to minimize the impact of changes in their movement patterns resulting from the injury.

Do the Pelvic and Thorax Movements Differ between the Sexes and Influence Golf Club Velocity in Junior Golfers?

The aim of this study was to determine the differences in golf swing execution in terms of the parameters of the pelvis and thorax movement between the sexes in junior golfers and their relation to the golf club velocity. Elite female and male players (age: 15.4 ± 1.0 and 15.8 ± 1.7 years, respectively) performed 10 golf swings with a driver under laboratory conditions. Pelvis and thorax movement parameters and golf club velocities were measured using a three-dimensional motion capture system. Statistical parametric mapping analysis of pelvis–thorax coupling revealed a significant difference (p < 0.05) between boys and girls during backswing. Analysis of variance showed a significant effect of sex on the parameters of maximal pelvic rotation (F = 6.28, p = 0.02), X-factor (F = 5.41, p = 0.03), and golf club velocity (F = 31.98, p < 0.01). No significant relationship was found between pelvis and thorax movement parameters and golf club velocity in the girls. We found a significant negative relationship between the parameters of maximal thorax rotation and golf club velocity (r = −0.941, p < 0.01) and between X-Factor and golf club velocity (r = −0.847, p < 0.05) in the boys. We suggest that these negative relationships in males were caused by the influence of hormones during their maturation and biological development, where there is decreased flexibility (lower shoulders rotation and X-factor) and growth of muscle strength (higher club head velocity).

Evaluation of Weight Shift and X-Factor During Golf Swing of Veterans With Lower Limb Loss

OBJECTIVE

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

DESIGN

Veterans with above or below knee limb loss participated in a 3-day adaptive golf event hosted by the Department of Veterans Affairs. Professional golf instructors educated participants on proper golf swing mechanics, after which kinematic analysis of trunk rotation and kinetic analysis of weight transfer between the legs during the golf swing were evaluated using three-dimensional motion capture and force platforms.

RESULTS

Golfers with a trail leg amputation, regardless of level of limb loss, demonstrated superior weight shift, whereas golfers with lead limb amputation showed greater X-Factor values (all P < 0.05). Golfers with below knee limb loss demonstrated better weight shift strategies compared to those with above knee limb loss, regardless of which leg was amputated (i.e., lead or trail limb, all P < 0.05).

CONCLUSIONS

Sports rehabilitation programs should focus on increased weight bearing on the prosthetic limb to achieve appropriate weight shift and increased flexibility to increase X-Factor values. Participation in such programs can offer both physical and psychosocial benefits and may be a valid tool to increase the overall quality of life of veterans with lower limb loss.

The swing performance Index: Developing a single-score index of golf swing rotational biomechanics quantified with 3D kinematics

Introduction

Golf swing generates power through coordinated rotations of the pelvis and upper torso, which are highly consistent among professionals. Currently, golf performance is graded on handicap, length-of-shot, and clubhead-speed-at-impact. No performance indices are grading the technique of pelvic and torso rotations. As an initial step toward developing a performance index, we collected kinematic metrics of swing rotational biomechanics and hypothesized that a set of these metrics could differentiate between amateur and pro players. The aim of this study was to develop a single-score index of rotational biomechanics based on metrics that are consistent among pros and could be derived in the future using inertial measurement units (IMU).

Methods

Golf swing rotational biomechanics was analyzed using 3D kinematics on eleven professional (age 31.0 ± 5.9 years) and five amateur (age 28.4 ± 6.9 years) golfers. Nine kinematic metrics known to be consistent among professionals and could be obtained using IMUs were selected as candidate variables. Oversampling was used to account for dataset imbalances. All combinations, up to three metrics, were tested for suitability for factor analysis using Kaiser-Meyer-Olkin tests. Principal component analysis was performed, and the logarithm of Euclidean distance of principal components between golf swings and the average pro vector was used to classify pro vs. amateur golf swings employing logistic regression and leave-one-out cross-validation. The area under the receiver operating characteristic curve was used to determine the optimal set of kinematic metrics.

Results

A single-score index calculated using peak pelvic rotational velocity pre-impact, pelvic rotational velocity at impact, and peak upper torso rotational velocity post-impact demonstrated strong predictive performance to differentiate pro (mean ± SD:100 ± 10) vs. amateur (mean ± SD:82 ± 4) golfers with an AUC of 0.97 and a standardized mean difference of 2.12.

Discussion

In this initial analysis, an index derived from peak pelvic rotational velocity pre-impact, pelvic rotational velocity at impact, and peak upper torso rotational velocity post-impact demonstrated strong predictive performance to differentiate pro from amateur golfers. Swing Performance Index was developed using a limited sample size; future research is needed to confirm results. The Swing Performance Index aims to provide quantified feedback on swing technique to improve performance, expedite training, and prevent injuries.

Golf Swing Biomechanics: A Systematic Review and Methodological Recommendations for Kinematics

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.

Is Golf a Contact Sport? Protection of the Spine and Return to Play After Lumbar Surgery

STUDY DESIGN

Narrative review.

OBJECTIVE

To address the gap in the literature on specific return to play protocols and rehabilitation regimens for golfers undergoing lumbar spine surgery with a high impact swing.

METHODS

This review did not involve patient care or any clinical prospective or retrospective review of patient information and thus did not warrant institutional review board approval. The available literature of PubMed, Medline, and OVID was utilized to review the existing literature.

RESULTS

Studies have shown that the forces through the lumbar spine in the modern-era golf swing are like other contact sports. Methods of protecting the lumbar spine include proper swing mechanics, abdominal and paraspinal musculature strengthening and flexibility as well as physical fitness. There are a variety of treatment options available to treat lumbar spine pathology each with a different return to play recommendations from doctors in the field.

CONCLUSIONS

With the introduction of a high impact, modern-era swing to the game of golf, the pathology is seen in the lumbar spine of both young, old, professional, and amateur golfers with low back pain are similar to other athletes in contact sports. Surgery is effective in returning athletes to a similar level of play even though no protocols exist for an effective and safe return. There have been many studies conducted to determine appropriate treatment and return to play for these injuries, but there is a gap in the literature on specific return to play protocols and rehabilitation regimens for golfers undergoing lumbar spine surgery with a high impact swing. As return to competitive play is important, especially with professional golfers, studies combining the use of swing mechanics changes, rehabilitation regimens and the type of surgery performed would be able to provide some insight into this topic now that golf may begin to be considered a contact sport.

Golf as a Physical Activity to Potentially Reduce the Risk of Falls in Older Adults with Parkinson's Disease

Advanced age is associated with an increased risk for falls in aging adults. Older adults are also more likely to be diagnosed with Parkinson’s disease (PD), with advanced age as the most significant risk factor. PD is a neurodegenerative disorder with four Cardinal motor symptoms: rigidity, bradykinesia, postural instability, and tremor. Thus, people (person)-with-Parkinson’s disease (PwP) have an even greater risk of falling than non-disorder age-matched peers. Exercise is an activity requiring physical effort, typically carried out to sustain or improve overall health and fitness, and it lowers the risk of falls in the general population. The sport of golf provides a low-impact all-around workout promoting a range of motion, activation of muscles in the upper and lower body, flexibility, and balance. Swinging a golf club offers a unique combination of high amplitude axial rotation, strengthening postural musculature, coordination, and stabilization, demonstrating the potential to impact PD symptoms positively. Golf may be a novel exercise treatment regimen for PD to use in conjunction with traditional medical therapy. We completed a literature review to determine the relationship between the game of golf, PD, and the risk of falls. We concluded that regularly playing golf can lower the risk for falls in community ambulating older adults with PD and demonstrates the potential to improve quality of life for PwP.

Small changes in ball position at address cause a chain effect in 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.

The Golf Movement Screen Is Related to Spine Control and X-Factor of the Golf Swing in Low Handicap Golfers

ABSTRACT

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.

Golf Swing Segmentation from a Single IMU Using Machine Learning

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.

Three Dimensional Upper Limb Joint Kinetics of a Golf Swing with Measured Internal Grip Force

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.

The Relationship Between the Golf-Specific Movement Screen and Golf Performance

CONTEXT

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

OBJECTIVE

To determine the relationship between the Titleist Performance Institute golf-specific functional movement screening (GSFMS) composite and individual element scores and golf performance by assessing a player's handicap, clubhead speed, side accuracy, ball speed, peak pelvis rotation speed, swing sequence, and common swing faults.

DESIGN

Cohort study, clinical measurement.

SETTING

English golf club.

PARTICIPANTS

A total of 11 amateur golfers: 5 males (age: 37.2 [18.7] y, height: 184.4 [9.6] cm, body mass: 89.5 [13.4] kg, and handicap: 9 [6.6]) and 6 females (age: 53.7 [15.0] y, height: 166.8 [5.5] cm, body mass: 67.9 [16.6] kg, and handicap: 13 [6.1]).

MAIN OUTCOME MEASURES

GSFMS composite and individual element scores and golf performance variables.

RESULTS

Significant relationships existed between GSFMS composite scores and handicap (r = -.779, P = .01); clubhead speed (r = .701, P = .02); ball speed (r = .674, P = .02); and peak pelvis rotation speed (r = .687, P = .02). Significant relationships existed between 90°/90° golf position and clubhead speed (r = .716, P = .01); ball speed (r = .777, P = .01); seated trunk rotation and peak pelvis rotation speed (r = .606, P = .048); single-leg balance and handicap (r = -.722, P = .01); torso rotation and handicap (r = -.637,P = .04); and torso rotation and peak pelvis rotation speed (r = .741, P = .01). Single-leg balance, overhead deep squat, and pelvic tilt were the GSFMS tests which participants had most difficulty in performing. The most common swing faults identified included loss of posture, slide, chicken winging, and early hip extension.

CONCLUSIONS

The GSFMS may be used to identify movement limitations that relate to golfing performance. These findings may potentially allow intervention to correct movement patterns and potentially improve golf performance.

The metabolic demand of external load carriage in golfers: a comparison of a single versus double-strap golf bag

BACKGROUND

A golf bag filled with a set of clubs provides a substantial load. When carried over distance this can increase the demands placed upon the golfer, leading to discomfort, fatigue and injuries. This study aimed to compare the metabolic demands of 2 methods of golf bag carriage.

METHODS

A total of 16 healthy male recreational golfers participated in the study. Participants were given an initial familiarization session in which their self-selected walking speed was determined. This was utilized as the treadmill speed for all subsequent trials. The testing protocol consisted of 3 randomized trials of treadmill walking for 5 minutes in each of three conditions: unloaded, single-strap bag and double-strap bag. Equipment consisted of a double-strap golf bag with a standard set of clubs weighing 12.5kg. For all trials oxygen consumption (L·min-1), VO2 (mL·kg·min-1) respiratory minute volume (VE) (L·min-1), and heart rate (HR) were measured.

RESULTS

Results showed that the double-strap bag required significantly less oxygen consumption (1.19±0.19 vs. 1.31±0.16 L·min-1, P<0.01) relative oxygen consumption (14.49±2.06 vs. 15.93±2.25 mL·kg·min-1, P<0.01), reduced respiratory minute volume (29.95±4.19 vs. 32.47±4.26 L·min-1, P<0.05), and lower heart rates (100.14±11.05 vs. 106.96±9.33 BPM, P<0.001) than the single-strap bag. Both methods of carriage showed significantly greater metabolic demands than the unloaded condition (P<0.05).

CONCLUSIONS

The decreased metabolic cost of carrying a double-strap golf bag may facilitate a reduction in fatigue and reduced mechanical stress. Golf bag transportation must therefore be recognized as a factor in reducing the risk of injury and improving playing performance.

Between-side differences in trunk rotational power in athletes trained in asymmetric sports

BACKGROUND

The asymmetric loading of trunk muscles in sports like golf or tennis may cause side-to-side imbalances in rotational muscle strength and endurance. Such imbalances may be compounded by the presence of low back pain (LBP) and related injuries. However, trunk rotational power is a better predictor of athlete performance, and therefore its ability to reveal these asymmetries/dysbalances should be investigated.

OBJECTIVE

This study compares peak and mean values of power during trunk rotations on the dominant and non-dominant side in golfers, ice-hockey players, tennis players, and an age-matched control group of fit individuals.

METHODS

Groups of 17 golfers, 17 ice-hockey players, 21 tennis players, and 39 fit individuals performed standing trunk rotations to each side with a bar weight of 5.5, 10.5, 15.5, and 20 kg placed on the shoulders. Peak power and mean power in the acceleration phase of trunk rotations were measured using the FiTRO Torso Premium system.

RESULTS

Peak power and mean power in the acceleration phase of trunk rotations were significantly higher on the dominant (D) than non-dominant (ND) side at weights of 5.5 kg (14 and 14%), 10.5 kg (17 and 14%), 15.5 kg (16 and 15%), and 20 kg (16 and 16%) in ice-hockey players, at 5.5 kg (14 and 13%), 10.5 kg (17 and 14%), and 15.5 kg (15% - only peak power) in tennis players, and at 5.5 kg (17 and 18%) and 10.5 kg (19 and 17%) in golfers. However, their values did not differ significantly at these weights (< 10%) in the age-matched control group. The D/ND ratio was the highest in ice-hockey players (1.18, 1.19), followed by golfers (1.16, 1.17) and finally tennis players (1.12, 1.16).

CONCLUSION

Taking into account significantly higher trunk rotational power on the dominant than the non-dominant side in golfers, tennis players and ice-hockey players at lower and/or higher weights and no significant side-to-side differences in a control group of fit individuals, this parameter may be considered specific to their asymmetric loading during trunk rotations. However, whether these asymmetries/dysbalances expressed by the D/ND ratio could also identify the likelihood of LBP, needs to be proven.

Kinematic determinants of performance parameters during golf swing

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 required number of trials for biomechanical analysis of a golf swing

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_ind). 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_ind 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_ind method for determining how many swings should be collected.

Return to Golf After Arthroscopic Management of Femoroacetabular Impingement Syndrome

PURPOSE

To investigate if patients who reported playing golf before arthroscopic hip surgery for femoroacetabular impingement syndrome were able to return to playing golf postoperatively.

METHODS

The study was a retrospective analysis of all consecutive patients undergoing hip arthroscopy for femoroacetabular impingement syndrome between 2012 and 2014. Inclusion criteria required that a patient (1) reported playing golf before the surgery, (2) had a minimum 2-year follow-up, and (3) completed patient-reported outcome measures. An electronic postoperative return to golf questionnaire was completed by patients who reported golf as an activity. To evaluate patients' ability to return to golf after surgery, the following variables were analyzed with paired samples t test and χ-square tests: handedness, holes played, modified-Harris Hip Score, and Hip Outcome Score Activity of Daily Living and Sports-Specific Subscale.

RESULTS

A total of 29 patients (22 men; age, 36.0 ± 11.9 years) with a minimum of 24 months of follow-up who self-reported playing golf preoperatively were included in the analysis. Preoperatively, 23 patients (79%) had discontinued golfing owing to activity-related hip complaints. At the final follow-up, all patients had significant improvements in the Hip Outcome Score Activity of Daily Living (preoperatively, 65.9 ± 19.9; postoperatively, 91.5 ± 12.8; P < .0001), the Hip Outcome Score Sports-Specific Subscale (38.2 ± 23.5, 79.7 ± 28.8; P = .0002), and modified-Harris Hip Score (54.8 ± 15.6; 84.2 ± 15.8; P < .0001). Additionally, there was a decrease in pain from 7.34 ± 1.63 to 1.71 ± 2.3 postoperatively (P < .0001), and 97% of patients returned to golf at an average of 7.2 months postoperatively. Postoperatively, 55% of patients (n = 16) noted improved golfing performance, 41% (n = 11) returned to their preinjury level, 1 patient (3%) returned at a lower level owing to non-hip-related problems, and 1 (3%) did not return to golf owing to fear of reinjury.

CONCLUSIONS

Arthroscopic treatment of femoroacetabular impingement syndrome in patients who reported playing golf before surgery resulted in significant improvements in hip function and predictably high rates of patient satisfaction, with 97% returning to golfing activity and 55% noting improvement from preinjury sporting performance.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Golf Swing Rotational Velocity: The Essential Follow-Through

Objective

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.

Methods

Rotational velocities of the upper-torso and pelvis throughout the golf swing and in relation to phases of the golf swing were examined in 11 professionals and compared to 5 amateurs using three-dimensional motion analysis.

Results

Peak rotational velocities of professionals were highly consistent, demonstrating low variability (coefficient of variation [COV]), particularly upper-torso rotational velocity (COV=0.086) and pelvic rotational velocity (COV=0.079) during down swing. Peak upper-torso rotational velocity and peak X-prime, the relative rotational velocity of uppertorso versus pelvis, occurred after impact in follow-through, were reduced in amateurs compared to professionals (p=0.005 and p=0.005, respectively) and differentiated professionals from most (4/5) amateurs. In contrast, peak pelvic rotational velocity occurred in down swing. Pelvic velocity at impact was reduced in amateurs compared to professionals (p=0.019) and differentiated professionals from most (4/5) amateurs.

Conclusion

Golf swing rotational velocity of professionals was consistent in pattern and magnitude, offering benchmarks for amateurs. Understanding golf swing rotational biomechanics can guide swing modifications to help optimize performance and prevent injury.

Partial swing golf shots: scaled from full swing or independent technique?

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%, p = 0.004, d = 2.26), combined with moderate reductions in lateral shift (25.5%, p = 0.004, d = 0.33) and smaller reductions in trunk rotation (arm to vertical at top of backswing: 14.1%, p = 0.002, d = 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.

The Teleology of the Thumb: On Purpose and Design

The Andrew J. Weiland Medal is presented by the American Society for Surgery of the Hand to a midcareer researcher dedicated to advancing patient care in the field of hand surgery. The Weiland Medal for 2017 was presented to the author at the annual meeting of the American Society for Surgery of the Hand. The purpose of this article is to present current evidence on how biomechanics and morphology influence the pathophysiology of thumb carpometacarpal joint osteoarthritis.

The role of pelvis-thorax coupling in controlling within-golf club swing speed

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.

Performance and Kinematic Differences in Putting between Healthy and Disabled Elite Golfers

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.

The Influence of X-Factor (Trunk Rotation) and Experience on the Quality of the Badminton Forehand Smash

No existing studies of badminton technique have used full-body biomechanical modeling based on three-dimensional (3D) motion capture to quantify the kinematics of the sport. The purposes of the current study were to: 1) quantitatively describe kinematic characteristics of the forehand smash using a 15-segment, full-body biomechanical model, 2) examine and compare kinematic differences between novice and skilled players with a focus on trunk rotation (the X-factor), and 3) through this comparison, identify principal parameters that contributed to the quality of the skill. Together, these findings have the potential to assist coaches and players in the teaching and learning of the forehand smash. Twenty-four participants were divided into two groups (novice, n = 10 and skilled, n = 14). A 10-camera VICON MX40 motion capture system (200 frames/s) was used to quantify full-body kinematics, racket movement and the flight of the shuttlecock. Results confirmed that skilled players utilized more trunk rotation than novices. In two ways, trunk rotation (the X-factor) was shown to be vital for maximizing the release speed of the shuttlecock – an important measure of the quality of the forehand smash. First, more trunk rotation invoked greater lengthening in the pectoralis major (PM) during the preparation phase of the stroke which helped generate an explosive muscle contraction. Second, larger range of motion (ROM) induced by trunk rotation facilitated a whip-like (proximal to distal) control sequence among the body segments responsible for increasing racket speed. These results suggest that training intended to increase the efficacy of this skill needs to focus on how the X-factor is incorporated into the kinematic chain of the arm and the racket.

Comparison of Muscle Onset Activation Sequences between a Golf or Tennis Swing and Common Training Exercises Using Surface Electromyography: A Pilot Study

Aim. The purpose of this pilot study is to use surface electromyography to determine an individual athlete's typical muscle onset activation sequence when performing a golf or tennis forward swing and to use the method to assess to what degree the sequence is reproduced with common conditioning exercises and a machine designed for this purpose. Methods. Data for 18 healthy male subjects were collected for 15 muscles of the trunk and lower extremities. Data were filtered and processed to determine the average onset of muscle activation for each motion. A Spearman correlation estimated congruence of activation order between the swing and each exercise. Correlations of each group were pooled with 95% confidence intervals using a random effects meta-analytic strategy. Results. The averaged sequences differed among each athlete tested, but pooled correlations demonstrated a positive association between each exercise and the participants' natural muscle onset activation sequence. Conclusion. The selected training exercises and Turning Point™ device all partially reproduced our athletes' averaged muscle onset activation sequences for both sports. The results support consideration of a larger, adequately powered study using this method to quantify to what degree each of the selected exercises is appropriate for use in both golf and tennis.

Inter-joint coordination between hips and trunk during downswings: Effects on the clubhead speed

Understanding of the inter-joint coordination between rotational movement of each hip and trunk in golf would provide basic knowledge regarding how the neuromuscular system organises the related joints to perform a successful swing motion. In this study, we evaluated the inter-joint coordination characteristics between rotational movement of the hips and trunk during golf downswings. Twenty-one right-handed male professional golfers were recruited for this study. Infrared cameras were installed to capture the swing motion. The axial rotation angle, angular velocity and inter-joint coordination were calculated by the Euler angle, numerical difference method and continuous relative phase, respectively. A more typical inter-joint coordination demonstrated in the leading hip/trunk than trailing hip/trunk. Three coordination characteristics of the leading hip/trunk reported a significant relationship with clubhead speed at impact (r < -0.5) in male professional golfers. The increased rotation difference between the leading hip and trunk in the overall downswing phase as well as the faster rotation of the leading hip compared to that of the trunk in the early downswing play important roles in increasing clubhead speed. These novel inter-joint coordination strategies have the great potential to use a biomechanical guideline to improve the golf swing performance of unskilled golfers.

The effect of oral motor activity on the athletic performance of professional golfers

Human motor control is based on complex sensorimotor processes. Recent research has shown that neuromuscular activity of the craniomandibular system (CMS) might affect human motor control. In particular, improvements in postural stability and muscle strength have been observed as a result of voluntary jaw clenching. Potential benefits of jaw aligning appliances on muscle strength and golf performance have also been described. These reports are highly contradictory, however, and the oral motor task performed is often unclear. The purpose of our study was, therefore, to investigate the effect of submaximum biting on golf performance via shot precision and shot length over three different distances. Participants were 14 male professional golfers - seven with sleep bruxism and seven without - randomly performing golf shots over 60m, 160m, or driving distance while either biting on an oral splint or biting on their teeth; habitual jaw position served as the control condition. Statistical analysis revealed that oral motor activity did not systematically affect golf performance in respect of shot precision or shot length for 60m, 160 m, or driving distance. These findings were reinforced by impact variables such as club head speed and ball speed, which were also not indicative of significant effects. The results thus showed that the strength improvements and stabilizing effects described previously are, apparently, not transferable to such coordination-demanding sports as golf. This could be due to the divergent motor demands associated with postural control and muscle strength on the one hand and the complex coordination of a golf swing on the other. Interestingly, subjects without sleep bruxism performed significantly better at the short distance (60 m) than those with bruxism. Because of the multifactorial etiology of parafunctional CMS activity, conclusions about the need for dental treatment to improve sports performance are, however, completely unwarranted.

Kinetic and Kinematic Differences in a Golf Swing in One and Both Lower Limb Amputees

Amputee golfers need to cope with the absence of sole proprioception, a decreased range of swing motion and other factors which should be recognized for training purposes. The aim of this study was to determine the kinetic and kinematic differences in the golf swing in one leg and two legs amputees. The participants consisted of two males and one female at a professional or amateur level with a different degree of disability. Each participant was taped by 3D markers and performed five golf swings with the iron 6. The intraclass correlation coefficient (ICC) did not vary between individuals in kinematics, however, it was low in kinetic variables of two leg amputees. The Kendal rank correlation showed a significant relationship between the level of amputation and a large number of kinetic and kinematic variables such as X factor, O factor, S factor and individual body angles. The fluency and similarity of the golf swing did not depend on the level of amputation. One lower limb amputation did not seem to increase movement variability contrary to two lower limb amputation. The most variable parameter was a weight-shift in all golfers. The takeaway and horizontal force angle depended on the level of amputation rather than individual technique, thus, their modification by training may be difficult. Estimation of golf swing „mistakes” in amputees in respect to the leading arm in an early follow or late follow position appeared to be useless.

The 2014 ABJS Nicolas Andry Award: The puzzle of the thumb: mobility, stability, and demands in opposition

BACKGROUND

The paradoxical demands of stability and mobility reflect the purpose and function of the human thumb. Its functional importance is underscored when a thumb is congenitally absent, injured, or afflicted with degenerative arthritis. Prevailing literature and teaching implicate the unique shape of the thumb carpometacarpal (CMC) joint, as well as its ligament support, applied forces, and repetitive motion, as culprits causing osteoarthritis (OA). Sex, ethnicity, and occupation may predispose individuals to OA.

QUESTIONS/PURPOSES

What evidence links ligament structure, forces, and motion to progressive CMC disease? Specifically: (1) Do unique attributes of the bony and ligamentous anatomy contribute to OA? (2) Can discrete joint load patterns be established that contribute to OA? And (3) can thumb motion that characterizes OA be measured at the fine and gross level?

METHODS

We addressed the morphology, load, and movement of the human thumb, emphasizing the CMC joint in normal and arthritic states. We present comparative anatomy, gross dissections, microscopic analysis, multimodal imaging, and live-subject kinematic studies to support or challenge the current understanding of the thumb CMC joint and its predisposition to disease.

RESULTS

The current evidence suggests structural differences and loading characteristics predispose the thumb CMC to joint degeneration, especially related to volar or central wear. The patterns of degeneration, however, are not consistently identified, suggesting influences beyond inherent anatomy, repetitive load, and abnormal motion.

CONCLUSIONS

Additional studies to define patterns of normal use and wear will provide data to better characterize CMC OA and opportunities for tailored treatment, including prevention, delay of progression, and joint arthroplasty.

Golf-related low back pain: a review of causative factors and prevention strategies

Golf is a popular sport with both perceived and real health benefits. However, certain injury risks are also prevalent, particularly to the lower back. Epidemiological studies have shown that lower back pain (LBP) from golf account for between 18% and 54% of all documented ailments, leading many researchers to regard the condition as the most common golf injury.

The purpose of this review was to examine the scientific literature to ascertain the risk factors associated with the development of LBP from playing golf and suggest methods to modify or limit these factors. Results of the review indicate that the high frequency of LBP appears multi-factorial although the asymmetrical and forceful nature of the swing along with excessive play and practice, particularly amongst elite players, appear to be common factors. Other factors include swing flaws leading to excessive side-bend and over-rotation of the spine, abnormal muscle recruitment, poor trunk endurance, restricted lead hip internal rotation and the use of unnecessarily stressful club transportation methods. Methods to help control or eliminate excessive stress on the lower back would include reducing the amount spent playing or practicing, seeking professional assistance to assess and adjust swing mechanics, improve trunk and hip flexibility, increase the strength and endurance of the trunk musculature, consider different footwear options and avoid carrying the golf bag. Adopting some or all of these recommendations should allow players to continue to enjoy the sport of golf well into their senior years.

Validity of the X-factor computation methods and relationship between the X-factor parameters and clubhead velocity in skilled golfers

The purpose of this study was to assess the validity of the X-factor computation methods and to examine whether direct relationships exist between the X-factor parameters and the clubhead velocity in a group of skilled male golfers (n = 18, handicap = -0.6 +/- 2.1). Five driver trials were captured from each golfer using an optical motion capture system (250 Hz). Two plane-based methods (conventional vs. functional swing plane-based) and one Cardan rotation-based method (relative orientation) were used to compute select X-factor (end of pelvis rotation, top of backswing, ball impact (BI), and maximum), X-factor stretch (stretch and maximum stretch), and X-factor velocity (BI and maximum) parameters. The maximum clubhead velocity was extracted and normalized to golfer's body height to eliminate the effect of body size. A one-way repeated MANOVA revealed that the computation methods generated significantly different X-factor parameter values (p < 0.001). The conventional method provided substantially larger X-factor values than the other methods in the untwisting phase and the meaningfulness of select X-factor parameters generated by this method was deemed questionable. The correlation analysis revealed that the X-factor parameters were not directly related to the maximum clubhead velocity (both unnormalized and normalized).