Kinematic Analysis of Swing in Pro and Amateur Golfers

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.

Synchronized metronome training induces changes in the kinematic properties of the golf swing

The purpose of this study was to evaluate possible effects of synchronized metronome training (SMT) on movement dynamics during golf-swing performance, as captured by kinematic analysis. A one-group, between-test design was applied on 13 male golfers (27.5 +/- 4.6 years old, 12.7 +/- 4.9 handicap) who completed 12 sessions of SMT over a four-week period. Pre- and post-assessments of golf swings with three different clubs (4-iron, 7-iron, and pitching wedge) were performed using a three-dimensional motion capture system. Club velocity at three different swing phases (backswing, downswing, and follow-through) was measured and cross-correlation analysis of time-series signals were made on joint couplings (wrist-elbow-shoulder) of both arms, and between joints and the club, during the full golf swing. There were significantly higher cross-correlations between joint-couplings and concomitant changes of the associated phase-shift differences, as well as reduced phase-shift variability at post-test. No significant effect of SMT was found for the club velocities. We suggest that domain-general influences of SMT on the underlying brain-based motor control strategies lead to a more coordinated movement pattern of the golf-swing performance, which may explain previous observations of significantly improved golf-shot accuracy and decreased variability after SMT.

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).

A methodological approach for the biomechanical cause analysis of golf-related lumbar spine injuries

A new methodological approach employing mechanical work (MW) determination and relative portion of its elemental analysis was applied to investigate the biomechanical causes of golf-related lumbar spine injuries. Kinematic and kinetic parameters at the lumbar and lower limb joints were measured during downswing in 18 golfers. The MW at the lumbar joint (LJ) was smaller than at the right hip but larger than the MWs at other joints. The contribution of joint angular velocity (JAV) to MW was much greater than that of net muscle moment (NMM) at the LJ, whereas the contribution of NMM to MW was greater rather than or similar to that of JAV at other joints. Thus, the contribution of JAV to MW is likely more critical in terms of the probability of golf-related injury than that of NMM. The MW-based golf-related injury index (MWGII), proposed as the ratio of the contribution of JAV to MW to that of NMM, at the LJ (1.55) was significantly greater than those at other joints ( < 1.05). This generally corresponds to the most frequent occurrence of golf-related injuries around the lumbar spine. Therefore, both MW and MWGII should be considered when investigating the biomechanical causes of lumbar spine injuries.

The X-Factor: an evaluation of common methods used to analyse major inter-segment kinematics during the golf swing

A common biomechanical feature of a golf swing, described in various ways in the literature, is the interaction between the thorax and pelvis, often termed the X-Factor. There is no consistent method used within golf biomechanics literature however to calculate these segment interactions. The purpose of this study was to examine X-factor data calculated using three reported methods in order to determine the similarity or otherwise of the data calculated using each method. A twelve-camera three-dimensional motion capture system was used to capture the driver swings of 19 participants and a subject specific three-dimensional biomechanical model was created with the position and orientation of each model estimated using a global optimisation algorithm. Comparison of the X-Factor methods showed significant differences for events during the swing (P < 0.05). Data for each kinematic measure were derived as a times series for all three methods and regression analysis of these data showed that whilst one method could be successfully mapped to another, the mappings between methods are subject dependent (P <0.05). Findings suggest that a consistent methodology considering the X-Factor from a joint angle approach is most insightful in describing a golf swing.

Movement variability in the golf swing

Traditionally, golf biomechanics has focused upon achieving consistency in swing kinematics and kinetics, whilst variability was considered to be noise and dysfunctional. There has been a growing argument that variability is an intrinsic aspect of skilled motor performance and plays a functional role. Two types of variability are described: 'strategic shot selection' and 'movement variability'. In 'strategic shot selection', the outcome remains consistent, but the swing kinematics/kinetics (resulting in the desired ball flight) are free to vary; 'movement variability' is the changes in swing kinematics and kinetics from trial to trial when the golfer attempts to hit the same shot. These changes will emerge due to constraints of the golfer's body, the environment, and the task. Biomechanical research has focused upon aspects of technique such as elite versus non-elite kinematics, kinetics, kinematic sequencing, peak angular velocities of body segments, wrist function, ground reaction forces, and electromyography, mainly in the search for greater distance and clubhead velocity. To date very little is known about the impact of variability on this complex motor skill, and it has yet to be fully researched to determine where the trade-off between functional and detrimental variability lies when in pursuit of enhanced performance outcomes.

Variability in clubhead presentation characteristics and ball impact location for golfers' drives

The purpose of the present study was to analyse the variability in clubhead presentation to the ball and the resulting ball impact location on the club face for a range of golfers of different ability. A total of 285 male and female participants hit multiple shots using one of four proprietary drivers. Self-reported handicap was used to quantify a participant's golfing ability. A bespoke motion capture system and user-written algorithms was used to track the clubhead just before and at impact, measuring clubhead speed, clubhead orientation, and impact location. A Doppler radar was used to measure golf ball speed. Generally, golfers of higher skill (lower handicap) generated increased clubhead speed and increased efficiency (ratio of ball speed to clubhead speed). Non-parametric statistical tests showed that low-handicap golfers exhibit significantly lower variability from shot to shot in clubhead speed, efficiency, impact location, attack angle, club path, and face angle compared with high-handicap golfers.

Differences in wrist mechanics during the golf swing based on golf handicap

OBJECTIVES

Variation in swing mechanics between golfers of different skill levels has been previously reported. To investigate if differences in three-dimensional wrist kinematics and the angle of golf club descent between low and high handicap golfers.

DESIGN

A descriptive laboratory study was performed with twenty-eight male golfers divided into two groups, low handicap golfers (handicap = 0-5, n = 15) and high handicap golfers (handicap ≥ 10, n = 13).

METHODS

Bilateral peak three-dimensional wrist mechanics, bilateral wrist mechanics at ball contact (BC), peak angle of descent from the end of the backswing to ball contact, and the angle of descent when the forearm was parallel to the ground (DEC-PAR) were determined using an 8 camera motion capture system. Independent t-tests were completed for each study variable (α = 0.05). Pearson correlation coefficients were determined between golf handicap and each of the study variables.

RESULTS

The peak lead arm radial deviation (5.7 degrees, p = 0.008), lead arm radial deviation at ball contact (7.1 degrees, p = 0.001), and DEC-PAR (15.8 degrees, p = 0.002) were significantly greater in the high handicap group.

CONCLUSION

In comparison with golfers with a low handicap, golfers with a high handicap have increased radial deviation during the golf swing and at ball contact.

Rotational Biomechanics of the Elite Golf Swing: Benchmarks for Amateurs

The purpose of this study was to determine biomechanical factors that may influence golf swing power generation. Three-dimensional kinematics and kinetics were examined in 10 professional and 5 amateur male golfers. Upper-torso rotation, pelvic rotation, X-factor (relative hip-shoulder rotation), O-factor (pelvic obliquity), S-factor (shoulder obliquity), and normalized free moment were assessed in relation to clubhead speed at impact (CSI). Among professional golfers, results revealed that peak free moment per kilogram, peak X-factor, and peak S-factor were highly consistent, with coefficients of variation of 6.8%, 7.4%, and 8.4%, respectively. Downswing was initiated by reversal of pelvic rotation, followed by reversal of upper-torso rotation. Peak X-factor preceded peak free moment in all swings for all golfers, and occurred during initial downswing. Peak free moment per kilogram, X-factor at impact, peak X-factor, and peak upper-torso rotation were highly correlated to CSI (median correlation coefficients of 0.943, 0.943, 0.900, and 0.900, respectively). Benchmark curves revealed kinematic and kinetic temporal and spatial differences of amateurs compared with professional golfers. For amateurs, the number of factors that fell outside 1–2 standard deviations of professional means increased with handicap. This study identified biomechanical factors highly correlated to golf swing power generation and may provide a basis for strategic training and injury prevention.

Thorax and pelvis kinematics during the downswing of male and female skilled golfers

Thorax and pelvis motion during the golf swing have most frequently been described for male golfers at discrete points during the swing, such as top of backswing (TBS) and ball contact (BC). Less is known about the continual motion and coordination of the thorax and pelvis throughout the downswing for either male or female golfers. The purpose of this study was to present detailed 3D kinematic profiles of thorax and pelvis motion during the downswing, and to determine if differences in kinematics exist between male and female skilled golfers. Thorax and pelvis data were collected from 19 male (26+/-7 years) and 19 female (25+/-7 years) skilled golfers (handicap < or =4) using an optical motion analysis system. 3D segment position, orientation and angular velocity were calculated, along with phase plane trajectories and thorax-pelvis separation angles. At BC males had greater pelvis posterior tilt, greater pelvis and thorax lateral tilt to the right, and less pelvis and thorax axial rotation to the left compared to females. Males achieved greater peak thorax and pelvis angular velocity, and angular velocity at BC, in the anterior-posterior and lateral tilt directions. Phase plane trajectories revealed that males and females had similar thorax lateral tilt and anterior-posterior tilt angular velocity-displacement relationships at TBS, yet by BC males had greater tilt angles and velocities compared to females. Collectively, the results suggest that male and female skilled golfers have different kinematics for thorax and pelvis motion, predominantly for lateral and anterior-posterior tilt. What might be considered optimal swing characteristics for male golfers should not be generalized to female golfers.

Competitive elite golf: a review of the relationships between playing results, technique and physique

Elite golfers commonly use fitness and technical training to become more competitive. The aim of this paper was to review the literature regarding the relationships between elite golfers' playing results, technique and physique. The competitive outcome is a direct function of the score. The three golf statistical measures that show the strongest correlations to scoring average are greens in regulation (GIR), scrambling, and putts per GIR. However, more detailed game statistics are needed where the distances to the targets are known before and after the strokes. Players affect ball displacement by controlling clubhead velocity and clubface angle during club and ball impact. X-factor studies have produced ambiguous results, possibly caused by different definitions of upper torso, rotation and top of backswing. Higher clubhead speed is generally associated with larger spinal rotation and shoulder girdle protraction at the top of the backswing. It is also associated with higher ground reaction forces and torques, a bottom-up and sequential increase of body segment angular velocities, a rapid increase of spinal rotation and a late adduction of the wrists during the downswing. Players can increase the clubhead speed generated by a swinging motion by actively adding a force couple. Wrist, elbow and shoulder force couple strategies should be differentiated when investigating the technique. Physical parameters such as anthropometrics, strength and flexibility are associated with skill level and clubhead speed. Current studies have investigated the linear correlation between arm and shaft lengths and clubhead speed, but a quadratic relationship may be stronger due to changes in moment of inertia. Fitness training can increase and perhaps decrease the clubhead speed and striking distance, depending on training methods and the player's fitness and level of skill. Future studies may focus on individual training needs and the relationship between physique, execution and its relation to accuracy of impact and ball displacement.

Upper extremity injuries in golf

Golf is an asymmetric sport with unique patterns of injury depending upon the skill level. Higher handicap players typically experience injuries that result from swing mechanics, whereas lower handicap and professional players have overuse as the major cause of their injuries. The majority of shoulder injuries affecting golfers occur in the nondominant shoulder. Common shoulder injuries include subacromial impingement, rotator cuff pathology, glenohumeral instability, and arthritis involving the acromioclavicular and/or glenohumeral joints. Lead arm elbow pain resulting from lateral epicondylosis (tennis elbow) is the leading upper extremity injury in amateur golfers. Tendon injury is the most common problem seen in the wrist and forearm of the golfer. Rehabilitation emphasizing improvement in core muscle streng is important in the treatment of golf injury. Emerging treatments for tendinopathy include topical nitrates, ultrasound-guided injection of therapeutic substances, and eccentric rehabilitation. There is evidence supporting physiotherapy, and swing modification directed by a teaching professional, for treatment of upper extremity golf injuries. This article focuses on upper extremity injuries in golf, including a discussion of the epidemiology, causes, diagnosis, treatment, and prevention of injuries occurring in the shoulder, elbow, wrist, and hand.