Swing Kinematics Research Articles

Wearable resistance acutely enhances club head speed in skilled female golfers

Golf is a skill-based sport which requires optimal swing mechanics to improve golf performance. As practitioners seek training methods to improve swing kinetics without compromising swing kinematics, loading through wearable resistance is one training modality which enables the golf swing to be performed in an overloaded manner. The purpose of this research therefore was to explore the acute effects of wearable resistance on golf swing performance measures. A randomised cross-over design was used with five skilled female golfers (22.0 ± 2.5 years, 163.1 ± 3.3 cm, 57.1 ± 3.4 kg and handicap 4 ± 1.2) who performed a series of golf shots with and without wearable resistance of 1.6 kg (∼2.8% body mass) attached laterally to the posterior trail side of the body. Flightscope launch monitor and force plate technology were used to quantify changes in club head speed and ground reaction forces. Using a paired t-test used for statistical analysis, significant ( p < 0.05) acute increases were found in club head speed (3.5%, p = 0.03), relative vertical ground reaction forces (11.4%, lead side, p = 0.01) and relative mediolateral ground reaction forces (7.1%, trail side, p = 0.03) with wearable resistance as compared to the unloaded condition. Wearable resistance enables a player to perform golf shots in an overloaded manner resulting in significant improvements in club head speed. Future research is required to assess the long-term adaptations to this form of loading on golf swing performance.

The Effects of Various Weighted Implements on Baseball Swing Kinematics in Collegiate Baseball Players.

Williams, CC, Gdovin, JR, Wilson, SJ, Cazas-Moreno, VL, Eason, JD, Hoke, EL, Allen, CR, Wade, C, and Garner, JC. The effects of various weighted implements on baseball swing kinematics in collegiate baseball players. J Strength Cond Res 33(5): 1347-1353, 2019-The purpose of this study was to investigate the effects of different warm-up (WU) devices on bat swing parameters including maximal resultant velocity (MRV), resultant velocity at ball contact (RVBC), time difference between MRV and RVBC, bat angle at MRV, bat angle at RVBC, and perceptual differences of each WU implement used by National Collegiate Athletic Association Division-I baseball players. Fifteen varsity baseball players completed 1 experimental session during fall training. Retroreflective markers were placed on the bat and tee to measure basic bat kinematics during the swing. Participants completed a general calisthenics WU before being counter-balanced into 1 of 4 WU conditions: standard bat (SB) (33 in/30 oz), fungo (10.6 oz), weighted gloves with SB (weighted gloves) (55.6 oz) and donut with SB (donut) (55.6 oz). Each participant was asked to perform their normal on-deck routine over a 2-minute period, finishing with 5 practice swings with the designated condition. After completion of the WU, a 1-minute rest period (simulating normal game conditions) was given to allow each participant to get set to perform 5 maximal swings with a SB. Five, 1 × 4 (group × condition) repeated measures analysis of variance examined the aforementioned variables. There were no significant differences in MRV, RVBC, time difference between MRV and RVBC, and bat angle at MRV and RVBC between all WU conditions. If presented with the current options, athletes should choose the WU implement with which they are most comfortable using before an at-bat situation.

Biomechanical analysis of the golf swing: methodological effect of angular velocity component on the identification of the kinematic sequence.

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. Thirteen golfers participated in this study and performed driver swings in a motion capture laboratory. Seven methods based on different component selection of segmental angular velocities (vector norm, component normal-to-sagittal, frontal, transversal and swing planes, segment longitudinal component and a method mixing longitudinal and swing plane components) were tested. Results showed the critical influence of the component chosen to identify the kinematic sequence with almost as many kinematic sequences as the number of tested methods for every golfer. One method seems to show the strongest correlation to performance but none of them can be assessed as a reference method for the identification of the golf swing kinematic sequence. Regarding the limited time lag between the different peak occurrences and the uncertainty sources of current materials, development of simulation studies would be more suitable to identify the optimal kinematic sequence for the golf swing.

Lumbar Spine Injuries: Primary Prevention in Amateur and Professional Golf Players.

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.

Changes in golf swing kinematic sequence after 12 weeks of reactive neuromuscular training using inertia overloading

[Purpose] We examined the influence of reactive neuromuscular training (RNT) on golf swing coordination. RNT aims to induce proper coordinative movement by exaggerating the performer’s mistakes. Therefore, we applied RNT using inertia overloading to golfers who have problems with kinematic sequence during a golf swing. [Methods] To examine the effect of 12 weeks of RNT on golf swing coordination, we employed a ball tracking system (launch monitor) and motion analysis system (inertia sensors) were taken on four consecutive periods (pre-test and post-tests 4, 8, and 13 weeks later). Thirty Korean male cadets were divided into three groups based on inertial loading and practiced 7-iron golf swings combined with specific group tasks twice per week. [Results] At pre-test, most participants reached maximal angular velocity near the impact timing (95-100%). However, the deceleration timing of the maximum angular velocity of the proximal segments gradually moved toward mid-downswing as the training sessions proceeded, with the RNT group ultimately outperforming the two control groups. Additionally, the RNT group showed a significantly higher maximum angular velocity in the thorax and wrist. [Conclusion] Our results suggest that RNT can be sufficient to elicit and effective whole-body coordination pattern. Considerable follow-up research is needed on the use of RNT for various sports tasks and the effects of expertise on RNT results.

Acute Effects of a Resistance Tubing Training Device on Baseball Swing Kinematics

Objective: The purpose of this study was to assess the acute kinematic changes that occur on the youth baseball swing following use of a resistance tubing training device. Methods: Kinematic data were collected on 10 subjects (13.2 ±1.9 years of age; 161.8 ±17.4 cm; 54.4 ±15.9 kg) at 240 Hz using Flock of Birds electromagnetic tracking system (TrackSTAR™, Ascension Technologies Inc., Burlington, VT., USA) synced with The MotionMonitor® (Innovative Sports Training, Chicago, IL., USA). Participants were required to hit 5 baseballs off of a tee with intention to hit line drives up the middle. At the completion of a three-minute rest, the participants were equipped with the resistance tubing training device and asked to perform 20 low effort dry swings. Subjects were then asked to hit 5 baseballs off a tee while wearing a resistance tubing training device and then 5 more off the tee without wearing a resistance tubing training device. Data were analyzed for the pre-device and post-device hits. Results: A repeated-measures multivariate analysis of variance revealed no significant differences pre-resistance and post-resistance tubing training device for center of mass over base of support (COM over BOS) or segmental velocities (Λ=0.68, F4,6=0.72, p=0.608). Conclusion: The absence of a significant decrease in segmental velocities could expose a resistance tubing training device as an appropriate warm-up tool and beneficial training aid. Because the resistance tubing training device is not detrimental to segmental velocities in the acute sense, it should be considered a practical sport-specific training aid.

Effects of nine weeks isokinetic training on power, golf kinematics, and driver performance in pre-elite golfers

BackgroundIt 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.MethodsTwenty competitive pre-elite golfers (handicap better than −3.0), 13 men and 7 women, were split into two groups, one group received the isokinetic power training (IK) alongside their normal isotonic pre-season strength-training and the other group continued with their normal isotonic pre-season strength-training regime (IT). The IK group completed 12 sessions of isokinetic power training on a standing rotation exercise (10% body weight at 1 m/s) and barbell squat (25 kg plus 10% body weight at 0.5 m/s). The IT group continued with their normal isotonic pre-season strength-training regime. Participants were tested for rotational power, lower body power, golf swing kinematics, and driver performance before and after a nine-week training period.ResultsAfter the nine-week training period both the IK and the IT groups increased their dominant side rotational force and power (effect sizes between 0.50–0.96) and magnitude based inference indicated that IK had a likely (> 80%) more beneficial increase in dominant side rotational force and power. For swing kinematics, IK had a likely (> 80%) more beneficial improvement in lead arm speed and acceleration compared to the IT group. For driver performance, IK had a possible (65%) beneficial effect on ball speed and likely (78%) beneficial effect on carry distance when compared to IT, whereas neither of the groups improved club head speed.ConclusionIn the present study on pre-elite golfers we found that 9 weeks of isokinetic training increased seated rotational force and power, peak arm speed and arm acceleration, ball speed, and carry distance more compared to isotonic training. Even though isokinetic training did not increase CHS, it did result in greater carry distance.

Static and dynamic accuracy of a magnetic-inertial measurement unit used to provide racket swing kinematics

Magnetic-inertial measurement units (MIMUs) are becoming more prevalent in sports biomechanics and may be a viable tool to evaluate kinematic parameters. This study examined the accuracy of a MIMU to estimate orientation angles under static conditions and dynamically from a squash racket during a forehand drive shot. A MIMU was mounted onto a goniometer and moved through 0–90°, with static data collected at 10° increments during 10 repetitions of all three axes. Typical error analyses showed the MIMU to be very reliable (TE ≤ 0.03°). MIMU accuracy was determined via intraclass correlation coefficients (ICC) (r > 0.999, p < 0.001). An ordinary least products regression showed no proportional bias and minimal fixed bias for all axes. Dynamic accuracy was assessed by comparing MIMU and optical motion capture data of squash racket swing kinematics. A MIMU was fixed onto a racket and 10 participants each hit 10 forehand shots. Mean orientation angle error at ball impact was <0.50° and ICC showed very high correlations (r ≥ 0.988, p < 0.001) for all orientations. Swing phase root mean squared errors were ≤2.20°. These results indicate that a MIMU could be used to accurately and reliably estimate selected racket swing kinematics.

The most important “factor” in producing clubhead speed in golf

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

An examination of the correlation amongst trunk flexibility, x-factor and clubhead speed in skilled golfers

ABSTRACTSkilled golfers are reported to be more flexible than lesser able golfers, which may assist in increased x-factor (shoulder–pelvis separation) at the top of the backswing. However, it is unknown if increased flexibility produces faster clubhead speed. The aim of this study was to investigate the correlations amongst trunk flexibility and x-factor, as well as the association between flexibility and clubhead speed in low handicap golfers. Fifteen low handicap male golfers who displayed a modern swing, had their trunk static anatomical end-range of motion (flexibility) and driver swing kinematics were measured. Although Pearson correlations revealed trunk extension and lateral bending were moderately related to x-factor, axial rotation flexibility was not. A generalised linear model (GLM) reported three axial rotation flexibility variables, and six golf swing kinematic variables were associated with faster clubhead speed. The Pearson correlation results suggest that skilled golfers who have increased axial rotation flexibility do not necessarily utilise it to increase x-factor, and the GLM results support the importance of multisegment flexibility and interaction for improving golf performance with skilled golfers.

A preliminary investigation of trunk and wrist kinematics when using drivers with different shaft properties

It is unknown whether skilled golfers will modify their kinematics when using drivers of different shaft properties. This study aimed to firstly determine if golf swing kinematics and swing parameters and related launch conditions differed when using modified drivers, then secondly, determine which kinematics were associated with clubhead speed. Twenty high level amateur male golfers (M ± SD: handicap = 1.9 ± 1.9 score) had their three-dimensional (3D) trunk and wrist kinematics collected for two driver trials. Swing parameters and related launch conditions were collected using a launch monitor. A one-way repeated measures ANOVA revealed significant (p ≤ 0.003) between driver differences; specifically, faster trunk axial rotation velocity and an early wrist release for the low kick point driver. Launch angle was shown to be 2° lower for the high kick point driver. Regression models for both drivers explained a significant amount of variance (60–67%) in clubhead speed. Wrist kinematics were most associated with clubhead speed, indicating the importance of the wrists in producing clubhead speed regardless of driver shaft properties.

The effects of baseball bat mass properties on swing mechanics, ground reaction forces, and swing timing

Swing trajectory and ground reaction forces (GRF) of 30 collegiate baseball batters hitting a pitched ball were compared between a standard bat, a bat with extra weight about its barrel, and a bat with extra weight in its handle. It was hypothesised that when compared to a standard bat, only a handle-weighted bat would produce equivalent bat kinematics. It was also hypothesised that hitters would not produce equivalent GRFs for each weighted bat, but would maintain equivalent timing when compared to a standard bat. Data were collected utilising a 500 Hz motion capture system and 1,000 Hz force plate system. Data between bats were considered equivalent when the 95% confidence interval of the difference was contained entirely within ±5% of the standard bat mean value. The handle-weighted bat had equivalent kinematics, whereas the barrel-weighted bat did not. Both weighted bats had equivalent peak GRF variables. Neither weighted bat maintained equivalence in the timing of bat kinematics and some peak GRFs. The ability to maintain swing kinematics with a handle-weighted bat may have implications for swing training and warm-up. However, altered timings of kinematics and kinetics require further research to understand the implications on returning to a conventionally weighted bat.

Swing Kinematics Described in Division I Female Softball Players

Swing Kinematics Described in Division I Female Softball Players

Arm swing in human walking: What is their drive?

Although previous research has studied arm swing during walking, to date, it remains unclear what the contribution of passive dynamics versus active muscle control to arm swing is.In this study, we measured arm swing kinematics with 3D-motion analysis. We used a musculoskeletal model in OpenSim and generated dynamic simulations of walking with and without upper limb muscle excitations. We then compared arm swing amplitude and relative phase during both simulations to verify the extent to which passive dynamics contribute to arm swing.The results confirm that passive dynamics are partly responsible for arm swing during walking. However, without muscle activity, passive swing amplitude and relative phase decrease significantly (both p<0.05), the latter inducing a more in-phase swing pattern of the arms. Therefore, we conclude that muscle activity is needed to increase arm swing amplitude and modify relative phase during human walking to obtain an out-phase movement relative to the legs.

Swing kinematics of male and female skilled golfers following prolonged putting practice

Given that males and females respond differently to endurance-based tasks, prolonged putting practice may provide an avenue to examine gender-related differences in golf swing kinematics. The aim of this project was to determine if 40 min of putting affects thorax and pelvis kinematics during the full swing of males and females. Three-dimensional trunk kinematics were collected during the swings of 19 male (age: 26 ± 7 years, handicap: 0.6 ± 1.1) and 17 female (age: 24 ± 7 years, handicap: 1.4 ± 1.7) golfers before and after 40 min of putting. Angular displacement at address, top of backswing and ball contact for the pelvis, thorax, and pelvis–thorax interaction were calculated, in addition to the magnitude of peak angular velocity and repeatability of continuous segment angular velocities. Female golfers had less pelvis and thorax anterior–posterior tilt at address, less thorax and thorax–pelvis axial rotation at top of backswing, and less pelvis and thorax axial rotation and pelvis lateral tilt at ball contact pre- to post-putting. Analysis of peak angular velocities revealed that females had significantly lower thorax–pelvis lateral tilt velocity pre- to post-putting. In conclusion, an endurance-based putting intervention affects females’ thorax and pelvis orientation angles and velocities to a greater extent than males.

Three-Dimensional Kinematics Observed Between Different Clubs during the Full Golf Swing

Three-Dimensional Kinematics Observed Between Different Clubs during the Full Golf Swing It has been documented that the golf swing should be identical for all clubs, yet biomechanical studies of the mechanics of the golf swing obtained with different clubs are somewhat lacking. The aim of the current investigation was to determine the three-dimensional kinematic differences in full body swing kinematics when using three different clubs (driver, 9 iron and 6 iron). Thirty five skilled male golfers performed maximal velocity swings using each of the three clubs. Full body 3D kinematics were obtained using an eight camera motion capture system operating at 500 Hz. Differences between clubs were examined using repeated measures ANOVA’s and the similarity of the 3D kinematic waveforms were inspected using intraclass correlations. The results showed that the 3D kinematics waveforms from the three clubs generally exhibited a high level of similarity R2 ≥ 0.861. However, both club head velocity and stance width were significantly greater when using the driver. It was also revealed that the torso, hip and knee were significantly more extended when using the driver. Thus before the notion that the mechanics of the golf swing are similar between clubs can be accepted, additional work is required.

Address Position Variability in Golfers of Differing Skill Level

This study aimed to determine whether differences in variability at address exist between golfers of low and high handicaps. A consistent shot type was employed by 20 golfers from 2 skill groups over 10--15 shots with a midiron. Kinematics analysis revealed only one significant difference between skill levels: the alignment relationship between the stance and shoulders, with the high skill golfers demonstrating reduced variability. Whole group variability was significantly reduced between the distance of the ball and the midpoint of the stance, pelvis and shoulders. Alignment variability also significantly decreased toward distal segments of the kinematic sequence where variable error decreased between the alignment of stance relative to shoulders and pelvis relative to shoulders with no effect of skill level. Results suggest the more distal segments of the kinematic sequence present a greater need for reduced detrimental variability. Coaches should ensure that golfers understand the importance of shoulder alignment in relation to the stance and how on course slopes and lies can influence the positions presented at address for distal segments of the golf swing kinematic sequence.

Three-dimensional trunk kinematics in golf: between-club differences and relationships to clubhead speed

The aims of this study were (i) to determine whether significant three-dimensional (3D) trunk kinematic differences existed between a driver and a five-iron during a golf swing; and (ii) to determine the anthropometric, physiological, and trunk kinematic variables associated with clubhead speed. Trunk range of motion and golf swing kinematic data were collected from 15 low-handicap male golfers (handicap = 2.5 ± 1.9). Data were collected using a 10-camera motion capture system operating at 250 Hz. Data on clubhead speed and ball velocity were collected using a real-time launch monitor. Paired t-tests revealed nine significant (p ≤ 0.0019) between-club differences for golf swing kinematics, namely trunk and lower trunk flexion/extension and lower trunk axial rotation. Multiple regression analyses explained 33.7–66.7% of the variance in clubhead speed for the driver and five-iron, respectively, with both trunk and lower trunk variables showing associations with clubhead speed. Future studies should consider the role of the upper limbs and modifiable features of the golf club in developing clubhead speed for the driver in particular.

The Effect of an 8-Week Plyometric Exercise Program on Golf Swing Kinematics

Previous research on conditioning in golf has looked at the effect of physical training programs on outcome measures of golf swing performance, namely club head speed and ball displacement. The current study examined the effect of an 8-week golf specific plyometric training program on the kinematics of the golf swing. Sixteen skilled golfers were randomly assigned to either an experimental or control group. Three-dimensional swing kinematic data were collected on shots with a 6 iron pre and post the training intervention. Statistical analyses were used to identify any changes in swing kinematics after the training intervention. Results showed that the experimental group increased lead arm and hand speeds in the downswing after training. This was accompanied by increases in maximum X-factor during the downswing and maximum rate of recoil of the X-factor. In conclusion, a program of golf specific plyometric training can potential lead to improvements in variables related to club head speed and ball displace...

Repeatability of three-dimensional thorax and pelvis kinematics in the golf swing measured using a field-based motion capture system

Field-based methods of evaluating three-dimensional (3D) swing kinematics offer coaches and researchers the opportunity to assess golfers in context-specific environments. The purpose of this study was to establish the inter-trial, between-tester, between-location, and between-day repeatability of thorax and pelvis kinematics during the downswing using an electromagnetic motion capture system. Two experienced testers measured swing kinematics in 20 golfers (handicap ≤ 14 strokes) on consecutive days in an indoor and outdoor location. Participants performed five swings with each of two clubs (five-iron and driver) at each test condition. Repeatability of 3D kinematic data was evaluated by computing the coefficient of multiple determination (CMD) and the systematic error (SE). With the exception of pelvis forward bend for between-day and between-tester conditions, CMDs exceeded 0.854 for all variables, indicating high levels of overall waveform repeatability across conditions. When repeatability was compared across conditions using MANOVA, the lowest CMDs and highest SEs were found for the between-tester and between-day conditions. The highest CMDs were for the inter-trial and between-location conditions. The absence of significant differences in CMDs between these two conditions supports this method of analysing pelvis and thorax kinematics in different environmental settings without unduly affecting repeatability.