Thomas Clayton
Clay0079 - 2121668
Friday, 19 June 2015
Driving off the tee
The golf swing is a complex
whole body movement that uses the summation of momentum principle, to create
high endpoint velocity and maximum distance. (Bradshaw, Keogh, Hume, Maulder,
& Nortje, 2009) Although golf is played by
players with large variances in physical characteristics and technical ability
the biomechanical principals behind the optimisation of distance and accuracy
remain the same. Biomechanics
has a role in maximising the distance and accuracy of golf shots by providing
both qualitative and quantitative evidence of body angles, joint forces and
muscle activity patterns. ( Hume, Keogh, & Reid, 2005) The golf
swing is an example of a throw-like pattern where the kinetic chain
incorporates most segments of the body; with the rotation of the body preceding
rapid arm swing. (Blazevich, 2007)
Significant biomechanical principals discussed
include: newtons three laws, inertia, velocity, angular and linear velocity,
torque, summation of forces, projectile momentum and the kinetic chain.
Major Question
What are the optimal
biomechanical techniques for maximising driver distance and accuracy off the
tee?
The answer
When analysing the golf drive biomechanically the swing can
be broken down into five distinct phases. These phases include: the address,
back swing, top of back swing and beginning of down swing, downswing and contact
and follow through.
Address
The address refers to the static position the golfer is in before
they play the shot, optimal biomechanical positioning should align the golfer
to the target, establish dynamic and static balance and provide the optimal
shaft angel and grip on the club. In preparation
for the dynamic movement of the swing the golfer’s legs should be slightly bent
and pushed firmly into the ground, preparing to counter act the ground reaction
force and Newtons third law of equal and opposite reaction.  |
| Figure 1. Optimal address |
 |
| Figure 2. Reverse k stance |
Back Swing
The
golf swing consists of 3 parallel points pivotal to both force creation and
accuracy, these include: parallel point 1, consisting of the club shaft being
parallel to the ground at the beginning of the back swing (figure 3), parallel
point 2, when the front arm is parallel to the ground (figure 4) and parallel
point 3 related to parallel point 1 but on the downswing. The primary role of
the back swing is to provide a base link for the kinetic chain and to prepare
the muscles for force preduction in the downswing. ( Hume, Keogh, & Reid, 2005) As the golfer
begins to rotate in the back swing torque, defined as Force X distance is
delivered in an up down process. (Blazevich,
2007)
From the commencement of the back swing through to parallel point 1 a one piece
take away is considered optimal. As seen in figure 5 a one piece take away
refers to maintaining the triangle formed by the two arms and the chest
through to the end of the takeaway period at parallel point 1. Chua, Sella, & Lepha, 2010 found that the delayed release of the club and increased
back swing angle created from the one piece takeaway increased torque applied at
the mid-point of the shoulders resulting in improved club rotation and an
increase in club head velocity. As mentioned in the address phase, the reverse k stance
allows the golfers weight to shifted laterally onto to the back foot as the
range of hip rotation is increased as the left hip turns the pelvis away from
the target resulting in the arc of the swing being flattened. (Maddalozzo,
1987)
 |
| Figure 3. Parallel point 1 |
 |
| Figure 4. One piece take away |
 |
| Figure 5. Parallel point 2 |
Top of back swing and
beginning of down swing
In terms of force production the top of the back swing and
the beginning of the downswing is the most crucial point of the golf swing,
through a point known in golf as the X factor. The X factor refers to the
maximisation of the hip and shoulder angle, resulting in increased rotational
velocity and increased club head speed. Figure 6 outlines the correlation between
x factor stretch (shoulder rotation - hip rotation) and swing speed, reviling
that golfers should focus on creating separation between backward rotation of
the upper torso and pelvis. (Chua, Sella, & Lepha, 2010) In addition to
shoulder rotation research has reviled the benefit of left knee flexion for
right handed golfers at the top of the back swing, with results indicating that
for every one standard deviation increase in leading knee flexion angle, ball
velocity increased 0.203 standard deviations. (Chua, Sella, & Lepha, 2010) In order to maximise
distance at this stage of the swing considerable ground reaction forces should
be produced as the body weight is transferred from the back foot to the front
during the downswing. Optimal performance results in the effective utilisation
of momentum generated by bodily movements during the golf swing. ( Hume, Keogh,
& Reid, 2005)
 |
| Figure 6. X factor stretch |
Downswing
The purpose of the downswing is to return the club head
through the slot angle at the maximum velocity. Preceding the X factor the golfer
vigorously releases and rotates forward, as the body weight is shifted to the
leading foot, bringing the club head to the ball in 0.30 to 0.06 tenths
of a second. Figure 7 highlights
the slot angle created from the position of the shaft at address and the
position of the shaft at parallel point 2, figure 8 demonstrates the optimal
downswing through the centre of the slot angle. As the golf swing is a throw
like movement the kinetic chain in the downswing works sequentially in a bottom
up process as the swing progresses
from the legs, through the hips, lower back, upper back, shoulders, arms, and
then wrists. ( Nesbit & Serrano, 2005) When performed
optimally summation of forces is in play as the amount of kinetic energy
is greater than the sum of the parts. ( Hume, Keogh, & Reid, 2005) As the club travels from parallel point 3
to impact and the wrists unlock, the torque components rapidly decrease as the
wrists cannot keep up with the rotational speed of the club at contact,
resulting in all torque components working negatively. It is at this point that
the wrists transition into a free hinge arrangement as the golfer simply holds
on to the club as its momentum carries it to impact. In an example of Newtons 3rd
law, as the wrists begin to work negatively the straightening of the shaft
continues to accelerate the club head resulting in club head velocity peaking precisely
at impact. ( Nesbit & Serrano, 2005)
 |
| Figure 7. Slot angle |
 |
| Figure 8. Downswing through the slot angle |
Contact and follow
through
As the club comes through the slot angle during the
downswing not just velocity is important but also club face angle leading into contact.
As Newton's laws of motion predict during the golf swing significant
correlations are apparent between club head speed and total work, with total
work being classified as the ability to apply forces and torques in the
direction of motion during the downswing. Optimal performance results in higher
total work and the point of impact. As mentioned in the down swing it’s at this
time that arms take over from the wrists, pulling inwards and decreasing the
distance from the club to the upper torso, increasing acceleration (figure 9). (Hellstrom,
2009)
During impact the club face and the ball produces torque that can twist the
club face if the sweet spot of the club doesn’t make contact with the ball,
resulting in the ball loosing accuracy. When driving off the tee the golfer can
take advantage of moment of inertia, to counter act the torque of the contact.
Moment of inertia refers to the resistance an object has to torque. (Blazevich, 2007) In order to
eliminate excess torque golfers need to strike the ball where the moment of
inertia is largest, referred to as the sweet spot. After contact is made with
the ball and Newtons Third Law has occurred the golfer continues on the designated
swing path as the body decelerates the club head by using eccentric muscle
actions. The golfer should finish in a balanced position with the trunk facing
the target with the hips and left angle rotating to absorb the weight transferal.
( Hume, Keogh, & Reid, 2005)
 |
| Figure 9. Decrease of club distance |
Looking at Newtons Second Law: ‘the acceleration of an
object is proportional to the net force acting on it and inversely proportional
to the mass of the object’. (Blazevich, 2007) Using the club speed produced during the
previous phases of the swing, the subsequent ball speed and impact time of the
club on the ball can be used to work out the acceleration and force required to
move the ball at that speed.
F= ma
Change in acceleration
/ collision time = ball acceleration X the mass of the ball
For the sake of these calculations the ball will be taking
off at 283kph or 78.7 metres per second, approximately 1 and a half times the
club speed at impact with a contact time of 0.0005 seconds and golf ball mass of
.0459kg.
78.7 m/s / .0005
= 157,400 m/s/s
157,400 X .0459
= 7224.66n or 736.710kg
How can we use this information?
In terms of the game of golf this information can be used to
educated golfers of any level on the optimal biomechanical principals for
maximising distance and accuracy when driving off the tee. The breakdown of the
swing into the 5 phases: the address, back swing, top of back swing and beginning
of down swing, downswing and contact and follow through, outlines optimal
technique and a detailed understanding of how and why each technique is
considered optimal. An increased understanding of the swing mechanics and the
creation of increased swing velocity will also allow golfers to tailor the
angle of attack and loft of the club to suit their swing and corresponding swing
speed, maximising distance. As seen in figures 10 and 11 the importance of the correct
loft and spin on projectile motion cannot be understated, as too much loft and
a fast swing speed will result in the angle of the projectile being too high
while not enough loft and slow swing speed will result in the projectile angle
being too flat. The information can also be used by various golfing associations such as the USPGA in areas such as course creation and rules and regulations for golfing equipment, such as driver shafts and club faces, to ensure all equipment and technological innovations are within acceptable limits.
 |
| Figure 10. Swing speed to driver loft |
 |
| Figure 11. Golf Driver Loft and Max Distance |
In terms of other applications the biomechanical principals
outlined could be transferred to any sport with a throw-like pattern where the
kinetic chain incorporates segments of the body sequentially, including: cricket
and baseball batting, hockey, tennis etc. All other biomechanical principals analysed throughout the blog, such as Newtons Laws also have firm groundings in all other sports and skilled movement patterns.
References
Hume, P., Keogh, J., & Reid, D. (2005). The Role of Biomechanics in
Maximising Distance and Accuracy of Golf Shots. Sports Medicine,
429-449.
Nesbit, S., & Serrano, M. (2005). Work and Power Analysis of the Golf
Swing. Sport Science and Medicine, 520-533.
Blazevich, A. (2007). Sports Biomechanics, The Basics: Optimising Human
Perfromance. London: A&C Black Publishers.
Bradshaw, Keogh, Hume, Maulder, & Nortje. (2009). The Effect of
Biological Movement Variability on the Performance of the Golf Swing in High-
and Low-Handicapped Players. Research quarterly for exercise and sport,
185-196.
Chua, Y., Sella, T., & Lepha, S. (2010). The relationship between
biomechanical variables and driving performance during the golf swing. Journal
of Sports Sciences, 1251-1259.
Hellstrom, J. (2009). Competitive elite golf: a review of the relationships between playing results, technique and physique. Sports Medicine, 723-732.
Hellstrom, J. (2009). Competitive elite golf: a review of the relationships between playing results, technique and physique. Sports Medicine, 723-732.
Maddalozzo, J. (1987). An anatomical and biomechanical analysis of the
full golf swing. NSCA Journal, 74-79.
Miura, K. (2001). Parametric acceleration ± the effect of inward pull. Sports
Engineering, 75-86.
Figure 1. Golf - How bomb your driver. Me and my golf, Proudman and Ward, 2014. https://www.youtube.com/channel/UCTwywdg9Sw5xs4wdN-qz7yw
Figure 2. Golf - How bomb your driver. Me and my golf, Proudman and Ward, 2014. https://www.youtube.com/channel/UCTwywdg9Sw5xs4wdN-qz7yw
Figure 3. How to hit your driver dead straight. Me and my golf, Proudman and Ward, 2015. https://www.youtube.com/watch?v=oXpppIiEEZQ
Figure 5. How to hit your driver dead straight. Me and my golf, Proudman and Ward, 2015. https://www.youtube.com/watch?v=oXpppIiEEZQ
Figure 4. Perfect golf swing review. Backswing Chapter, Mann. J, 2007. http://perfectgolfswingreview.net/backswing.htm
Figure 6. Perfect golf swing review. Backswing Chapter, Mann. J, 2007. http://perfectgolfswingreview.net/backswing.htm
Figure 7. Nail your driver straight. Me and my golf, Proudman and Ward, 2014. https://www.youtube.com/watch?v=R81ZMI4V_bw
Figure 8. Nail your driver straight. Me and my golf, Proudman and Ward, 2014. https://www.youtube.com/watch?v=R81ZMI4V_bw
Figure 9. Parametric acceleration ± the effect of inward pull. Sports Engineering, Miura. K, 2001.
Figure 10. Malaysia's Golfing Commonity. My Golf.com. 2008. http://www.mygolf.com.my/phpbb2/viewtopic.php?t=10404&sid=1585b1a988ee120e2ca3859cfdeb2e82
Figure 11. Golf Driver Loft and Max Distance. Instant Golf Lesson, Cotter. R. 2015. http://www.instantgolflesson.com/golf-driver-loft-for-max-distance.php
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