Foreword: This blog will explore two key bio-mechanical concepts and four bio-mechanical questions, which are involved with maximising distance and accuracy of a golf drive.

The Answer

Magnus Effect:

The Magnus Effect (also known as the magnus force) is a key concept with regards to the accuracy of a golf drive. The Magnus Effect is defined as the ‘changing of trajectory of an object towards the direction of spin’ (Blazevich, 2012). This is a key concept in golf and plays a huge role in the direction a ball flies in the air. Occasionally, when a golf ball is struck, the ball will start straight, but then fade off to one side. The reason the ball starts to fade to one side is because of the golfer ‘pulling or drawing the club face across the ball slightly, which creates spin’ (Blazevich, 2012). This is illustrated in figure 2 where the golfer is generating spin on the ball by striking it with an angled club face, causing the ball to fade to one side. The reason that this causes the ball to fade to one side is because ‘a spinning ball grabs the air that flows past it because of the friction between the air and the ball and causes air on one side of the ball to slow down (High Pressure) and speed up on the other (Low Pressure)’ (Blazevich, 2012). This creates a pressure differential (Blazevich, 2012). This process is illustrated in figure 1. The spin on the ball causes it to fade towards the low pressure side, where the air is moving faster. This is also evident in figure 3, where a golf ball has had backspin imparted on the ball. The picture illustrates that the ball is being lifted up and dragged backwards. This means that the backspin will cause the ball to travel high up in the air but will not go very far, making it a perfect stroke for a lob shot onto the green or over a tree. Figure 4 illustrates the different trajectories a golfer can hit a golf ball using the theory of the magnus effect. Therefore, if a golfer wishes to maximize their accuracy and hit the ball straight, then they should hit the ball with a straight club face and follow through properly (Illustrated in box 4 in figure 5). This does not allow the ball to spin sideways, which allows the ball to go move in a straight direction.

Figure 1 – Example of a ‘Pressure Differential’ causing the 

ball to fade to the right (low pressure) 

Source: Blazevich, 2012, pg.188

Figure 2 – In figure A, the ball is struck with a straight club face, therefore the ball has minimal spin on it and goes straight. In figure B the ball is struck with a slightly angled club face generating side spin on the ball which causes it to fade to the right.

Source: Blazevich, 2012, pg.189

Figure 3 - Magnus Effect (Backspin)

Source: Vrentas, J. (2009). USGA Lab Keeps Technology (and the golf ball) From Going Too Far. Retrieved from  http://www.nj. com/golf/index. ssf/2009/06/michael_guillenthe_starledgert.html 

Figure 4 - Golf Ball Trajectories for a Right Hander

Source: Daniels, T. (2013). Hook or Slice – What’s the Difference?. Retrieved from http://www.tydaniels.com/hoo k-slice fade/. 

Figure 5 – Angle of Club and Follow Through Which Cause the Ball to Spin

Source - Blumer, R. & Chaney, R. (2013). Combining Swing Path and Face Angle. Retrieved from http://www.netplaces.com/golf-instruction/improving-your-accuracy/combining-swing-path-and-face-angle.htm.

Coefficient of Restitution:

The coefficient of restitution is another key concept involved in golf. The coefficient of restitution is defined as ‘the proportion of total energy that remains with the colliding objects after the collision’ (Blazevich, 2012). The coefficient of restitution can be affected by a lot of factors, such as speed of the swing of the golf stick, softness/hardness of the golf ball used and also temperature of the ball. Blazevich (2012) outlined that a ‘warmer golf ball had a coefficient of 0.80 (bounce height = 1.17m), but decreased to 0.67 (bounce height = 0.82m) when cooled’. Therefore, in order for a golfer to hit further, they should take advantage of this factor and keep their golf ball warm when playing. It should also be noted that ‘the golf ball deteriorates with each high speed impact against the golf club head, resulting in a lower value of the coefficient of restitution’ (Fan, 2011). Therefore, in order for a golfer to maximise the distance of their drives, they should regularly change to a new ball and also keep the ball warm. This will increase the coefficient of restitution and thus increase a golfer’s driving distance.

Figure 6 – Illustration of the change in ball compression when driven

Source: Barzeski, E.J. (2005). The Long Ball: Distance is Everything?. Retrieved from http://the sandtrap.com/b/balls/the_long _ball_distance_is_everything.  

How does the loft (angle of the club face) affect distance?

The angle which a golfer hits a golf ball in the air can also have an impact on both the distance and accuracy of a golf drive. The angle which a golfer hits a ball can be affected by the type of shot a golfer plays and also the loft of the face of the club the golfer uses. Blazevich (2012) has stated that ‘the maximum range of a projectile is determined partly by its angle of projection and also that when the angle is greater, the object attains a greater vertical height but lesser range’. Blazevich (2012) also stated that ‘when the angle of projection is too small, the object doesn’t have sufficient vertical velocity to attain a significant range’. As illustrated in figure 7, different types of drivers have different lofts. Generally, if a golf ball is optimally struck, the lower the angle of the club face, the further a ball will travel. This is because the lower angle of the club face causes the ball to travel lower to the ground when struck, thus the force imparted on the ball from the club, causes the golf ball to travel further horizontally, rather than vertically, thus more distance is achieved. This is also illustrated in figure 7, where the driver is listed as having the lowest loft angle out of all the clubs shown. This indicates that the driver is the best club to use in order to maximise distance. It should also be noted that ‘wind resistance also acts to change the motion of the ball, generally resulting in a reduction in horizontal velocity that ultimately reduces horizontal displacement (distance)’ (Hume et al., 2005). Therefore, if a golfer wishes to maximise his/her driving distance, then they should use a low lofted driver club and also analyse the direction of the wind on the day which they are playing, to determine where best to aim their drives to maximise distance.

Figure 7 – Different Club Lofts and How They Have Changed Over the Years

Source: Wishon, T. & Grundner, T. (2006). 12 Myths That Could Wreck Your Golf Game. 1-32. Retrieved from http://www.alanscustomclubs.com/_pdfs/12mythsBook.pdf

Figure 8 – Men’s Shaft Lengths of the Different Driver Clubs (In Inches). Note: 1 inch = 2.54 cm

Source: Australian Sporting Goods Association Inc. (2012). Golf Clubs Fact Sheet. Mulgrave, Victoria. Retrieved from http://www.asga.com.au/images/stories/file/fact_sheets/Golf_Clubs_Fact_Sheet.pdf.

How does the length of the golf club affect distance and accuracy?

The length of a golf stick also has a huge effect on the distance a person can drive a golf ball.  Research has shown that ‘the use of drivers of different shaft length alters both the distance that the ball will travel and the level of control that can be maintained’ (Kenny et al., 2008). The Australian Sporting Goods Association Inc. (2012) has backed up this information by stating that ‘the longer the club you use, the more club head speed is generated and thus more distance is a result’. In a recent study it has been found that ‘a driver hit on center at:

·        - 43 inches hits approximately 250 yards

·        - 43.5 inches hits approximately 262 yards

·        - 44 inches hits approximately 270 yards.

·        - 44.5 inches hits approximately 275 yards.

·        - 45 inches hits approximately 280 yards' 
(Australian Sporting Goods Association Inc., 2012) 

As you can see the longer the shaft of the golf stick, the further it is possible to drive a golf ball. This supported on a biomechanics level, as research has shown that ‘using a longer driver to strike the golf ball will create greater linear velocity at the distal end of the driver, thus imparting a greater initial velocity to the ball’, which if struck correctly, will increase the distance hit (Kenny & Wallace, 2008). Whilst using a longer golf stick to maximize linear velocity of the distal end of the golf stick is important, it is also important that a person ‘holds the club at the superior portion of the club handle and has his/her elbows extended at the point of contact’ (Hume et al., 2005). This will increase the length of the lever, thus further increasing the linear velocity at the distal end of the club, creating more force, which leads to an increase in driving distance. Blazevich (2012) has supported this when he stated that ‘a higher velocity can be obtained if we swing a racket/stick with our arms outstretched’.  It is also important that a golfer understands that ‘the longer the club used the more difficult it is to control a shot’ (Australian Sporting Goods Association Inc., 2012). Therefore, if a golfer wishes to maximize the distance of their drives, they should choose a driver with a longer shaft and extend their elbows (creating a higher linear velocity). However, because it is harder for a golfer to drive accurately with a longer driver, a golfer needs to find a driver club that best suits their game and height. The Australian Sporting Goods Association Inc. (2012) have supported this notion, when they stated that ‘it is not worth sacrificing accuracy for the minimal amount of distance gained by using a driver longer than 44 inches’. Therefore, to maximize distance and accuracy, a golfer should use a driver which is the correct size for their height/swinging style and is no longer than 44 inches.

How does the type of the golf ball affect distance and accuracy?

There are four main types of golf balls, which include a one-piece, two-piece, three-piece and a four-piece. These four types of golf balls, which are illustrated in figure 9, are all specifically made for maximizing either distance or control (reduce spin).

One Piece: One piece golf balls are generally for beginner golfers. They have a ‘soft feel and a low compression (therefore a low coefficient of restitution), which decreases the distance you can hit them’ (Fielding, 2010).

Two Piece: A two piece golf ball is designed to ‘ maximize distance (increase the coefficient of restitution) whilst also lower spin (reduce the magnus effect), which means slice or hook spin will not be as pronounced and the ball will fly straighter’ (Fielding, 2010).

Three Piece: A three piece golf ball is designed to ‘produce a very high spin rate (increase the magnus effect) which provides maximum control (pending on golfer's abilities) and feel’ (Fielding, 2010). 

Four Piece: A four piece golf ball is designed to produce ‘maximum distance for long hitting (maximize the coefficient of restitution)’ (Fielding, 2010).

Therefore, if a golfer wishes to maximize his/her driving distance they should consider using a four piece golf ball. However, this golf ball is specifically made for ‘professional and low handicap golfers as it is hard to control’ (Fielding, 2010). Therefore, when driving, golfers of average ability should use a two piece golf ball, as these balls are designed to produce less spin (minimize the magnus effect) and maximize distance (maximize coefficient of restitution).

 

Figure 9 – The 4 Different Types of Golf Balls (One Piece (Top Left), Two Piece (Top Right), Three Piece (Bottom Left) & Four Piece (Bottom Left))

Source: Fielding, T. (2010). Golf Balls: Common Golf Ball Types. 29, 1-4. Retrieved from http://www. agolfersguide.com/userfiles/file/Newsletter-agolfersguide%20newsletter-SEPT0910.pdf. 

How is summation of forces applied in golf driving?

The summation of forces generated in our body when swinging a golf stick, is also a key concept in maximising a person’s golf driving distance. Hume et al. (2005) have stated that ‘in order to maximize the velocity of the most distal segment (the club head), the movement should commence with the larger, proximal segments (e.g. hips & trunk) and proceed in a sequential manner to the smaller, more distal segments (e.g. upper arms and hands)’. These small movements hugely help increase the velocity of the club head and if the ball is struck optimally, result in an increase in the distance a golfer can hit. Therefore, for a golfer to increases their driving distance, they need to practice and develop their golf swinging action to allow a fluent movement starting from the hips/trunk and finishing in the upper arms/hands. This will help maximize the velocity of the club head and cause the ball to travel further when driven.

How Else Can We Use This Information?

This blog outlined the importance of two key bio-mechanical principles, being the coefficient of restitution, the magnus effect. We also explored the concept behind increasing lever length when striking a ball, the type of ball golfers should use, the ideal loft of the club golfers should use and also the benefits of fluent movement when swinging. These bio-mechanical principals can be applied to any sport where an object, such as a racket, stick or bat etc. is used to strike a ball. For example, the magnus effect is a key concept used in tennis as topspin and backspin are used a lot to execute certain shots. It is also applied in baseball, as a pitcher uses the concept of the magnus effect to move the ball in the air, in order to make it hard for the batter to hit the ball. The coefficient of restitution theory is used in an sports which require hitting an object such as cricket, baseball, and tennis etc. in order to hit the ball further. Therefore, as you can see, understanding these bio-mechanical principles can be very beneficial for almost any athlete, as they can be applied to all sports to improve performance.

Conclusion:

In conclusion, from this blog we have found that in order to maximize distance and accuracy of a drive, a golfer should:

• Extend their elbows and uses a long shafted driving club to maximize distance.
• Choose a low lofted driving club to maximize horizontal distance and minimize vertical distance of a golf drive.
• Keep their golf ball warm and regularly uses a new golf ball to maintain a high coefficient of restitution.
• Choose the appropriate golf ball to maximize distance and accuracy of a golf drive (Two piece for regular golfers)
• Work on fluently moving their body/muscles in a golfing action to promote force summation, leading to a higher velocity of the club head and in turn, an increase in distance of a golf drive.
• Correctly strike the ball and follow through, so the ball does not spin as much to one side (magnus effect), which improves the accuracy and also horizontal distance of a golf drive.

References:

Australian Sporting Goods Association Inc. (2012). Golf Clubs Fact Sheet. Mulgrave, Victoria. Retrieved from http://www.asga.com.au/images/stories/file/fact_sheets/Golf_Clubs_Fact_Sheet.pdf.

Barzeski, E.J. (2005). The Long Ball: Distance is Everything?. Retrieved from http://thesandtrap.com/b/ balls/the_long _ball_distance_is_everything

Blazevich, A. J. (2012). Sports Biomechanics: The Basics. Bloomsbury, London: A&C Black Publishers.

Blumer, R. & Chaney, R. (2013). Combining Swing Path and Face Angle. Retrieved from http://www. netplaces.com/golf-instruction/improving-your-accuracy/combining-swing-path-and-face-angle.htm. 

Daniels, T. (2013). Hook or Slice – What’s the Difference?. Retrieved from  http://www.tydaniels.com /hoo k-slice fade/.

Fan, H. F. (2011). Determination of Coefficient of Restitution on Modal Test Data. 1-6. Retrieved from  http://sem-proceedings.com/21i/sem.org-IMAC-XXI-Conf-s32p01-Determination-Coefficient-Restitution-Based-Modal-Test-Data.pdf

Fielding, T. (2010). Golf Balls: Common Golf Ball Types. 29, 1-4. Retrieved from http://www.agolfersguide .com/userfiles /file/Newsletter-agolfersguide%20newsletter-SEPT0910.pdf.

Hume, P.A., Keogh, J. & Reid, D. (2005). The Role of Biomechanics in Maximising Distance and Accuracy of Golf Shots. Sports Med, 35, 429-449.

Kenny, C. I., Wallace, S. E. & Otto, R. S. (2008). Influence of Shaft Length on Driving Performance. Sports Biomechanics, 3, 322-332.

Vrentas, J. (2009). USGA LabKeeps Technology (and the golf ball) From Going Too Far. Retrieved from http://www.nj. com/golf/index. ssf/2009/06/michael_guillenthe_starledgert.html 

Wishon, T. & Grundner, T. (2006). 12 Myths That Could Wreck Your Golf Game. 1-32. Retrieved from http://www.alanscustomclubs.com/_pdfs/12mythsBook.pdf.