Biomechanical Effects of Ball Position in the Golf Swing

Ball position is one of the important elements of address position. Ball position has been shown to affect distance, direction, trajectory or ball flight as well as club-head velocity at impact. One example conclusion from a previous study highlighting the precise nature of golf was that a variation in ± ¼ inch in ball position side to side changed the launch angle of the ball by ±3°. Let’s put this another way, keeping in mind that 3° is a typical difference in loft between neighboring irons; setting up with the ball just ¼ inch too forward in your stance can turn your 7 iron into more like an 8 iron, or ¼ inch too back in your stance can turn your 7 iron into a 6. Not good to carry the ball 10 yards farther or shorter than you intended.

Today’s post highlights an excellent study from 2018 out of South Korea published in the Journal of Sports Science and Medicine, entitled “Biomechanical Effects of Ball Position on Address Position Variables of Elite Golfers” (citation below). Many studies on ball position prior to the one highlighted in this post focused on ball flight but did not shed much light on what occurs biomechanically in the golfer. This study therefore set out to discover a biomechanical explanation on how ball position affects ball flight.

11 right-handed male professional golfers (average age ~28 years) volunteered to participate in this study. Participants hit golf balls with a 5 iron off an artificial turf surface into a net. 35 markers were placed on anatomical landmarks to track movement and position and collect biomechanical data. There were also 3 markers attached to the club head and 2 to the club shaft to track club-face aim, loft angle, and lie angle.

Participants warmed up then took their preferred address position, and then the position of each foot position and the ball were outlined. The participants were asked to perform full golf swings at their outlined foot position, while the researchers altered the ball position at address.  The ball was moved in the mediolateral direction (left/right from the golfer’s perspective) from their starting preferred position one-half and one full golf ball length to the left and to the right. The ball was also moved in the anteroposterior direction (farther/closer from the golfer’s perspective) from their starting preferred position one-half and one full golf ball length away and closer. See image below.

This study revealed possible biomechanical explanations for how alterations in ball position in both the mediolateral and anteroposterior directions can affect address position. With movement in the mediolateral direction, shoulder rotation and club-face aim rotated in the same direction as the golf ball, and the vertical ground reaction force increased toward the respective lead or trail leg. For movement in the anteroposterior direction, when the ball was moved closer, the trunk/hips/knees/ankles extended, the golfer’s center of gravity essentially shifted posteriorly, and the lie angle increased. Vice versa when the ball was moved farther away; the trunk/hips/knees/ankles flexed more, center of gravity moved anteriorly, and the lie angle decreased.

In summary, seemingly small changes in ball position at set up can statistically significantly affect your biomechanics and ball flight. It is important to maintain discipline and repeatability in your setup to maximize consistent results. The right ball position is different for each golfer. Especially if you’re struggling with consistency, it’s a worthwhile pursuit to find the best ball position for you and stick to it every time.

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Source:

Kim SE, Koh YC, Cho JH, Lee SY, Lee HD, Lee SC. Biomechanical Effects of Ball Position on Address Position Variables of Elite Golfers. J Sports Sci Med. 2018;17(4):589-598.