Gender differences in swing mechanics
1st October 2008 By: 18541
This article discusses two key differences that have been observed between elite male and elite female golfers. To date, most research that has evaluated the mechanics of the golf swing has focussed on the swings of elite male golfers. This is somewhat surprising given that it is reasonably obvious that men and women tend to have different swing patterns. This means the results of research that has focussed on male golfers may not be that applicable to female golfers. The scarcity of published findings pertaining to female golfers has led researchers at Griffith University (Gold Coast, Australia) to evaluate the swing mechanics of female golfers and then to compare the mechanics of men and women golfers. This article discusses two key differences that have been observed between elite male and elite female golfers.

Figure 1

The first step – swing mechanics of elite female golfers

When researching swing mechanics, the first step is to document the mechanics of elite players. This is because elite golfers generally demonstrate more consistent mechanics which makes it easy to measure and interpret the results. To illustrate the relatively low variability observed in skilled golfers, examine the graphs in Figure 2a and 2b. These graphs are from a very successful LET player currently playing on tour. Figure 2a illustrates how the pelvis rotates (or ‘turns’) during the swing. Each line represents a swing using a 5 iron. The vertical axis represents the amount of pelvic rotation (in degrees) while the horizontal axis represents the percentage of the downswing cycle. The first dashed line indicates the top of the backswing and the second dashed line indicates impact.

Figure 2a

Figure 2b

At first glance there doesn’t appear to be 5 different swings – each swing almost completely overlaps the other swings throughout the downswing! What this essentially means is that there is less than a few degrees difference in pelvic rotation between all 5 swings. These observations are even more remarkable when you consider that the 3D motion analysis system used to capture the swings (VICON) is accurate to within 1-2 degrees. Looking at the values in the Figure 2a, the pelvis reaches about 45 degrees of rotation at the top of the backswing and then very rapidly rotates in the opposite direction during the downswing. At impact the pelvis is rotated about 45 degrees to the left (or in an ‘open’ position), and has well and truly cleared out of the way as the club reaches impact. In Figure 2b, lateral flexion of the trunk (or side bend) can be observed throughout the downswing. The female golfer in this graph reaches maximal side bend (to the right) just after impact. Historically this has been referred to as the ‘crunch factor’ and is thought to be a contributing cause in the development of trunk and lumbar spine injuries in golfers. The other interesting observation from Figure 2a and 2b is the apparent increased variability near the top of backswing. There seems to be greater variability between swings during the transition from backswing to downswing, but the LET player in this example does an excellent job of getting each swing back into one particular ‘groove’ late in the downswing and through to impact. The implication here may be that skilled golfers can afford a certain amount of variability during the transition period but if it becomes too high, a poor shot results.

Figure 3a

Figure 3b

The second step – comparing swings of elite female and elite male golfers Gender differences in golf performance may be due to variations in body composition or physical factors such as flexibility or muscle strength. However, differences in swing mechanics may also further explain differences in performance that have been observed between male and female golfers.

Gender differences in the X-Factor One swing variable that has been investigated in skilled male golfers has been the ‘X-Factor’ or the pelvis-trunk differential (Figure 3a and 3b). X-Factor is often thought of as a performance measure, as a positive relationship exists between clubhead speed and X-Factor. That is, someone with a larger X-Factor tends to have a higher clubhead velocity. In Figure 3b, the graph shows the same female golfer from Figure 2a and 2b reaching maximal X-Factor angle (55 degrees) approximately 65% into the downswing cycle. An X-Factor of 55 degrees in a male golfer would correspond to someone with a low to average clubhead velocity. In females we are still not sure of what a ‘normal’ X-Factor angle would be. Preliminary results seem to suggest that females rotate both their pelvis and trunk more than males during the backswing, but fail to generate the difference between the two segments (X-Factor) that males do. Therefore a smaller X-Factor in females may be fairly common, and consequently be one possible reason why we see discrepancies in club head velocity between sexes.

Figure 4

Gender differences in timing All golfers are aware of the feeling they get when they hit a shot that ‘just feels right’. Typically, it is this shot that represents optimal timing. Timing has not been extensively studied in golf but has been investigated quite extensively in a number sports similar to golf (e.g. throwing a ball, swinging a bat, a serve in tennis). The overall result of this research is that to time a shot well, there needs to be an ordered sequence of body motion. This ordered sequence begins in the more proximal segments (i.e nearer to the centre of the body e.g. pelvis) and finishes in the more distal segments (e.g. hand and club). A proximal to distal sequence results in a ‘building’ of velocity as each segment rotates. This is critical for golfers, as we are all aware that maximal velocity at the most distal segment/s (hand and club) will result in hitting the golf ball further. In Figure 4 we can see an optimally timed shot, where the pelvis commences rotation followed by the trunk and finally the hand. It can also be observed that the peak angular velocity of each segment increases steadily over time and that the overall peak velocity occurs at the hand. This is conducive to maximising clubhead velocity. Possible differences in timing may exist between skilled male and female golfers, although little formal investigation can support these claims at present. It is feasible that females don’t generate clubhead velocity as high as males due to lower peak velocities in the hand and the club. Whether this is due to altered sequences of timing or physical differences such as strength and power remains to be seen and is the current focus of the research being conducted at Griffith University.

Relevance? So what does all this mean for male and female players? It is likely that certain key movements of the trunk and pelvis have a strong influence over the success of a full golf shot. Importantly, it appears that elite male and elite female golfers produce different patterns of trunk and pelvis motion but these patterns still produce consistent and successful outcomes. Questions that arise out of these findings are related to gender based differences in the relationship between the movements occurring during the swing, performance and risk for injury – watch this space!

References 1. Egret, C. I., B. Nicolle, et al. (2006). "Kinematic analysis of the golf swing in men and women experienced golfers." International Journal of Sports Medicine 27(6): 463-7. 2. Jobe, F. W., J. Perry, et al. (1989). "Electromyographic shoulder activity in men and women professional golfers." The American Journal of Sports Medicine 17(6): 782-7. 3. Neal, R. J., B. Abernethy, et al. (1990). The influence of club length and shot distance on the temporal characteristics of the swings of expert and novice golfers. Science and Golf: Proceedings of the First World Scientific Congress of Golf. A. J. Cochran. London, E & FN Spon: 36-42. 4. Sanders, R. H. and P. C. Owens (1992). "Hub movement during the swing of elite and novice golfers." International Journal of Sport Biomechanics 8(4): 320-330.

Article from Ladies European Tour:
Published: 1/10/2008

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