Men and Women Experienced Golfers

C. I. Egret 1,2 B. Nicolle 1 F. H. Dujardin 3 J. Weber 3 D. Chollet 1 Kinematic Analysis of the Golf Swing in Men and Women Experienced Golfers Abstract Golf has become an increasingly popular sport, which is enjoyed by both men and women. This paper addresses the question what differences may exist between men and women golfers. The purpose of this study is to analyze the kinematic pattern of the golf swing in both men and women experienced golfers. Seven male and five female golfers participated in the study. The measurements of kinematic data during swing were obtained with the optoelectronic system VICON (Oxford s Metrics, Oxford, UK) with five cameras operating at 50 frames per second. Clubhead speed was measured using a radar system (Bell- Tronics, Ltd, Covington, USA). A Mann-Whitney test (p = 0.05) showed that the women seem to produce a wide swing with larger hip and shoulder joint rotation angles at the top of the backswing. Men flexed their left knee more during the backswing, this may promote a greater weight transfer to the right side. Nevertheless, these two kinematic patterns showed no significant differences in the clubhead speed. Men probably used their increased knee flexion to compensate for their muscular and articular suppleness which is less than that of the women. The results of this study show that there is a specific swing for women. Key words Golf swing kinematic men women driver Introduction Golf has become an increasingly popular sport, which is enjoyed by both men and women. Nevertheless, the scientific literature evaluating the biomechanics of the golf swing is available in only a few articles in comparison with other sports, even considering the fact that substantial research has been in progress over the last two or three years. The golf swing has been studied in terms of the kinematics [2,4,7,18] and kinetics [8,17,19,21] in two or three dimensions, dynamics of weight shift [14], electromyographic analysis [1,12,16,20] and through the use of mathematical modelling [11]. However, only one study [10], to our knowledge, has involved the biomechanics of the golf swing for female golfers. The purpose of this study was to compare the EMG firing patterns on normal shoulder musculature in both sexes of experienced golfers. The visual analysis revealed that the women tended to have slightly more muscular activity during the takeaway and forward swing phases, compared to the men, who tended to have more activity during acceleration and followthrough, but the difference is not statistically significant. One other study [9] evaluated the effects of an eight-week conditioning program on selected measures of physical fitness and golf performance. The authors of this work are primarily interested in the effect of conditioning on the clubhead speed, and do not comment on any differences between the swings of men and women. 463 Affiliation 1 C.E.T.A.P.S. Laboratory, UPRES EA 3832, University of Rouen, Faculty of Sports Sciences, France 2 I.G.C. Society, Haras d Estimeauville, Saint-Arnoult, France 3 G.R.H.A.L. Laboratory, Rouen University Hospital Charles Nicolle, France Correspondence Dr Claire Egret University of Rouen Faculty of Sports Sciences CETAPS Laboratory Bld Siegfried 76821 Mont Saint Aignan France Phone: + 33231890375 Fax: + 33231890923 E-mail: claire_egret@yahoo.fr Accepted after revision: June 6, 2005 Bibliography Int J Sports Med 2006; 27: 463 467 Georg Thieme Verlag KG Stuttgart New York DOI 10.1055/s-2005-865818 Published online August 30, 2005 ISSN 0172-4622

Table 1 Characteristics of each group of men and women golfers tested (mean ± standard deviation) Groups n Age (years) Height (cm) Weight (kg) Handicap Men 7 23.1 ± 2.9 178.0 ± 5.1 72.8 ± 8.5 6.6 ± 1.7 Women 5 20.4 ± 4.2 167.6 ± 9.4 54.2 ± 5.7 6.1 ± 3.4 464 The scientific studies seem to specialize in the biomechanics of the male golf swing, to optimize the performance of the male golfers; which shows that the larger number of men practicing golf makes it more important than the women s golf. Most studies of the golf swing present the difference between the highly skilled, compared to the lesser skilled male golfers [4, 6, 8,15, 18,19]. However, professional tours reveal a similar incidence and types of injury for both men and women [10]. Therefore, it is interesting to understand the differences that exist between men and women golfers and especially between the male and female swing. Regarding morphological or physical differences, is there a specific swing for women? The paper addresses the question of what differences in the kinematic pattern of the golf swing may exist between men and women experienced golfers. Materials and Methods Subjects Seven male and five female experienced golfers participated in the study. The characteristics of each group are presented in Table 1. Skill level was determined by each subject s self reported United States Golf Association (USGA) Handicap. The participants received an explanation of the experimental protocol and provided informed consent prior to testing. Protocol The measurements of kinematic data during swing were established with the VICON (Oxford s Metrics, Oxford, UK) which uses five cameras operating at 50 frames per second. The cameras were linearised and the whole system calibrated according to manufacturer s instructions. The VAX 512 system (Digital Equipment Corporation, USA) was used to reconstruct the three-dimensional coordinates of passive markers composed of 25.4 mm-diameter spheres fixed with a double-face adhesive tape. These reflective markers were placed on following anatomical sites: left and right acromio-clavicular joint, epicondyles of each elbow, left and right apophysis styloid radius, left and right anterio-superior iliac spine, lateral condyles of each knee, and left and right lateral malleoli. Because recording at 50 frames per second does not allow an exact recording of the club head speed at the impact with the ball, a radar system (Launch Monitor) (Bell-Tronics, Ltd, Covington, USA) was used. The device was placed 0.5 m behind the ball which was on an indoor synthetic mat. Golfers, dressed in shorts and wearing golf shoes, performed five swings with their driver club. Fig.1 Men and women golfers were asked to swing as they normally would, relying on the subjects understanding of their best biomechanical swing, hitting the ball into an indoor nylon net. The swing was divided into the following two phases: 1. Backswing: from ball address to the top of the backswing, 2. Downswing: from the end of backswing to impact ball-club. To describe the differences between men and women golfers during the golf swing, several data were analyzed: hip joint rotation angles, shoulder joint rotation angles, elbow joint flexion angles, and knee joint flexion angles, and the speed of the clubhead. The zero reference of the hip and shoulder joint rotation angles was obtained when the biacromial and the bitrochanterian lines were in the frontal plane at the address. Fig.1 shows the angle measured for example of the shoulder joint rotation. The zero reference at the knee and elbow joint angles was obtained when the upper or the lower limbs were in complete extension [7]. Statistical analysis Data were analyzed using Mann-Whitney-test to determine significant differences between the men and women golfers. The level of significance was set at 0.05. Results Shoulder joint rotation angle measured. Angle data Fig. 2 shows the shoulder and hip joint rotation angles and the left knee joint flexion angles obtained for the two groups at the top of the backswing. The mean angles of the shoulder rotation at the top of the backswing were 84.1 ± 15.58 and 109.4 ± 18.88, respectively for the men and women golfers and 37.9 ± 8.18 and 63.9 ± 11.58 for the hip joint rotation angles. Statistical analysis indicated there were significant differences between the men and women golfers for these two angles tested. Statistical analysis indicated some significant differences between the men and women golfers for the left knee flexion angles at the top of the backswing. Men flexed their left knee to a greater extent than the women (35.3 ± 4.98 vs. 16.5 ± 5.68).

knowledge, only one study [10] involved the biomechanics of the female golf swing and especially the EMG firing patterns on normal shoulder musculature of women compared to that of male golfers. Therefore, it seems to be difficult to compare our results with the current scientific literature available. Yet, the discussion of this study was developed from the conclusions of studies carried out with the male golfers. Fig. 2 Shoulder and hip joint rotation angles at the top of the backswing between the men and women experienced golfers (mean ± standard deviation), * p < 0.05. The right and left elbow joint flexion angles are presented in Table 2. The statistical analysis indicated some significant differences between the men and the women golfers tested at the top of backswing and impact for the right elbow and at the top of the backswing for the left elbow. Stance The mean stance (distance between the two feet) at the address was 61.3 ± 4.3 cm vs. 52.6 ± 3.1 cm, respectively for the men and the women golfers. Statistical analysis indicated significant difference between the two groups tested. The same result is obtained if the height of each subject is taken into account: Ratio of the Stance/Height is 0.34 ± 0.02 for the men and 0.31 ± 0.01 for the women. Clubhead speed No significant difference was observed between the two golfer groups for the clubhead speed. The mean speed was 144.4 ± 15.9 km h 1 vs. 135.6 ± 13.7 km h 1, respectively for the men and the women experienced golfers. Discussion The aim of this study is to compare the kinematic pattern of the golf swing in both men and women experienced golfers. To our The measurements of the shoulder joint rotation angles at the top of the backswing has been previously discussed in several studies [4, 7, 9,13]. Overall, this angle, obtained with regard to the frontal plane, was on average 908. The results of our study obtained with the male golfers (84.1 ± 15.58) are in agreement with this mean value. However, the female experienced golfers produced significantly greater shoulder rotation angles (109.4 ± 18.88). Only the results of Burden et al. [4] reported that male professional golfers normally rotated their shoulders between 908 and 1328 with a mean of 109 ± 128 when using a driver club. This greater amplitude can be explained by an evaluation of overswing in the female experienced golfers tested. Nevertheless, the results of Jobe et al. [10] suggested that men and women demonstrated similar firing patterns in the shoulder muscles during the golf swing. But this finding does not preclude the possibility that there may be differences in muscle firing patterns and biomechanics in other parts of the body. These authors added that a visual, on the field analysis of the players raises the question of the role that the hips play in the golf swing and whether men and women have differences in hip movement. The measurements of the hip joint rotation angles at the top of the backswing obtained with regard to the frontal plane, was on average 458 [5]. In our study, the hip rotation joint angles at the top of the backswing was significantly different between the male and female golfers (respectively 37.9 ± 8.18 vs. 63.9 ± 11.58). The men rotated their hips with a lesser angle than the results reported in the study of Hetu et al. [9] which obtained 40.5 ± 14.58. As regards the shoulder joint rotation angles, the women had a greater hip rotation than that of the men. These two results suggest that male and female golfers have different swings. The reason for this may be that the muscular or articular suppleness is generally higher for the women than the men. Even so, a recent study [3] suggested that a restricted backswing may reduce the potential for injury without compromising performance. Bulbulian et al. [3] explained that a short backswing in golf may reduce trunk muscle activation and possibly reduce back injury and pain without negatively impacting swing accuracy or clubhead speed. 465 Table 2 Right and left elbow joint flexion angles at the address, top of backswing and impact between the two golfer groups tested (mean ± standard deviation) Elbow joint flexion angles Right elbow Left elbow address top of backswing impact address top of backswing impact Men 41.8 ± 8.48 131.5 ± 12.28 57.3 ± 20.18 38.0 ± 5.38 60.4 ± 12.38 50.9 ± 7.78 Women 37.4 ± 7.68 109.7± 17.38 49.2 ± 5.28 45.1 ± 12.28 44.1 ± 7.28 67.6 ± 10.58 Men vs. women NS * NS NS * NS NS = not significant; * p < 0.05

466 However, these authors added that the short swing increases shoulder muscle activation and may, in turn, promote risk for shoulder injury. The other results concerned the left knee joint flexion angles. Unlike the shoulder and hip joint rotation angles, the men flexed their left knee more at the top of the backswing than the women (35.3 ± 4.98 vs. 16.5 ± 5.68). This seems that to increase the swing arc with reduced shoulder and hip rotation angles, the men have increased knee joint flexion. The results of Richards et al. [17] showed that the highly skilled golfers are approaching a somewhat common weight pattern, whereas the less skilled golfers are extremely variable as a group. Gatt et al. [8] added that the knee joint forces and moments generated during the golf swing are not large enough for golf to be considered an activity with a high risk for traumatic knee injury. The other results of our study, which can be associated with the knee joint flexion angles, are the measurements of the width of stance at the address. We found that the mean stance of the men was significantly higher than the women (61.3 ± 4.3 cm vs. 52.6 ± 3.1 cm) even if we have taken into account the height of these two groups. For the men, this result is in agreement with Nagao and Sawada [14] who obtained 64.8 cm with the driver club. However, no study, to our knowledge, explains the width of stance measurement of the female golfers. Therefore, women on average have a reduced width of stance, and consequently the reduced base, compared to that of the men. Milburn [13] explained that the complex system of the golf swing can be approximated by the motion of a double pendulum consisting of an upper segment (the arm and the shoulder) hinged at the wrist to the lower segment (the club). Because men s arms are generally longer than women s, men have more leverage to drive the ball further: the typical driving distance for the men on the PGA Tour is 250 to 300 yards, whereas the women drive 230 to 250 yards [10]. Nevertheless, our results showed no statistical differences between the men and the women in the clubhead speed (respectively 144.4 ± 15.9 km h 1 vs. 135.6 ± 13.7 km h 1 ). The performance level of the men was comparable with the results of Burden et al. [4] who obtained 128.5 ± 1.4 km h 1 with the driver club or Hetu et al. [9] who obtained, after eight-week conditioning program, 134.0 ± 23.2 km h 1. However, other studies showed some greater values with the driver club: 189.3 km h 1 [2]; 203.5 km h 1 [13] which may be explained by the level of the subjects tested. As regards the last results, it is difficult to correlate the clubhead speed and the significant differences between the men and women with the right and left elbow angles at the top of the backswing. In fact, these two differences seem to be explained with the differential in the shoulder joint rotation angles associated with the physical characteristics of the suppleness. Conclusion The results from this study indicate that the golf swing is not identical between men and women golfers. The women seem to produce a swing with larger hip and shoulder joint rotation angles at the top of the backswing. Whereas, the men flexed their left knee more during the backswing than the women. But perhaps the men used this greater knee flexion angle only to compensate their poor suppleness. Nevertheless, these two kinematic results showed no significant differences in the clubhead speed, and therefore do not allow inferences to be drawn about swing efficiency. Bulbulian et al. 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