“ The Answer ”
Balance and stability:
In order to maximise
distance in a golf drive, balance and stability are crucial components. A
golfers ideal set up is to stand with their legs shoulder width apart, knees
slightly bent, with the line of gravity within the golfers base of support and
the core muscles activated (Hume, Keogh, & Reid, 2005).
 |
| Diagram of a golfer with feet shoulder with apart, knees slightly bent and line of gravity within base of support. |
The larger the area of
base of support the more stable the golfer is; however if it becomes too large
it can restrict movement (Blazevich, 2010). Therefore, shoulder width apart is the optimal width as it allows for
a stable base, whilst still allowing the fluent and complex movement of the
golf swing. Similarly, bending the knees improves balance and stability, as the
body’s centre of mass is closer to the base of support (Goehl, 2002).
This allows for improved stability as the body is well balanced. Finally, by
activating core muscles the body is kept rigid rather than wobbly, further
improving the golfers stability (Hume, Keogh, & Reid, 2005). A stable set up allows the golfer to
generate more force and club head velocity with his upper body whilst
maintaining balance, in order to exert maximum force and consequent distance on
the ball.
Ground Force Reaction:
According to newtons
third law ‘ for every action, there is an equal and opposite reaction’ (Blazevich,
2010:45). This is evident in golf
with the ground reaction force (GRF), which is the equal and opposite force the
ground exerts on the foot (Blazevich, 2010). To increase this GRF, the legs need to be bent and pushed into the
ground in order to give the force necessary to accelerate, in a specific,
opposite, direction (Chu, Sell &
Lephart, 2010). In relation to the golf drive, the
player loads the right foot during the backswing and then transfers their
weight to the left foot during the down swing which can generate a greater club
head velocity at ball impact (Chu, Sell &
Lephart, 2010).
 |
| Transfer of weight from right foot to left foot during the golf drive. |
By ensuring adequate GRF is being
applied, maximum club head velocity can be achieved at ball impact (Hume, Keogh, & Reid, 2005). Evidence suggests that professional golfers have a considerably
higher GRF and faster weight transfer than amateur golfers (Hume, Keogh, & Reid, 2005). Further highlighting the importance of GFR and weight transfer and
its affect on overall ball distance.
Force:
In order to optimise
distance in the golf drive, maximum force production is vital to produce
maximum distance.
Force production is
made up of 3 main factors, summation of force, momentum and impulse (Hume, Keogh, & Reid, 2005). It is the combination of these factors that optimise force and
therefore the distance the ball will travel.
Summation of force:
Newton’s
second law of motion is the law of acceleration. The law indicates that the
greater the force applied to an object the greater its acceleration (Blazevich,
2010). Therefore, in order to maximise force, the body’s different forces
must be combined to generate optimal force, acceleration and therefore
distance. Summation of forces is the term used to describe the sequential order
of body parts combined to optimise force (Smith, 2010). This process begins with the larger body segments
producing force, which then is added to the smaller body segments, which is
then added to the smallest, faster body parts (Kenny, McCloy, Wallance
& Otto, 2008).
In the golf drive, summation
of force begins at the hips and trunk and sequentially progresses to the upper
arms and hands (Kenny, McCloy, Wallance & Otto, 2008). Through this sequential movement, optimal force is generated,
resulting in maximum velocity and therefore optimal distance. The harder and
faster a golf ball is hit the further it will travel.
The above diagram illustrates the summation of force
from distal to proximal muscles.
Momentum:
When an object is in motion,
it has a particular mass and velocity, the product of this is known as momentum
(Hume, Keogh, & Reid, 2005). Differences
in momentum are a result in ‘variations of mass and velocity’ (Blazevich, 2010:52). For
example, a heavier object will have a greater momentum than a lighter one
moving at the same velocity (Blazevich,
2010). However, because golfer equipments mass is
constant, velocity is the main factor affecting momentum. For example, if a golfer wants to hit
the ball further, they must swing the club faster, with a higher velocity in
order for it to travel further. Therefore, in order to generate optimal
momentum, the swing must generate a high club head velocity in order to maximize
distance of the golf shot.
Transfer of momentum:
The Transfer of
momentum is important in the golf drive, as momentum must be transferred from
the swing to the ball being struck. The transfer of momentum principal states
that momentum cannot be lost; simply it is transferred from one object to
another (Hume, Keogh, & Reid, 2005). Therefore, in golf it is imperative to
generate as much momentum during the swing as possible, in order to transfer
maximum momentum on the ball being struck. The greater the momentum the greater
the velocity of the ball and therefore the distance it will travel (Bradshaw, et.al., 2009).
 |
| Transfer of momentum from golf club to ball. |
Impulse:
The amount of force
needed to change the momentum of an object varies depending on the time that
the force is applied (Cochran, et.al., 2003). In golf, a large force is applied over a
short period of time. The combined effect of force and time is known as impulse
(Blazevich, 2010). In golf, the time of contact is very brief
and therefore it is not possible to increase the time, the only way impulse can
be increased is by increasing the force (Chu, Y., Sell, T. & Lephart.
(2010). Therefore, in order to
optimise the distance a golf ball will travel is dependent on the force
applied. The greater the force, the greater the momentum, therefore, velocity
and final distance the ball will travel.
Lever:
The principal of
leverages highlights that the velocity at the end of a longer lever is faster
than the velocity at the end of a shorter lever and that the end of a lever will move more
quickly than any other point on the lever (Blazevich, 2010).
 |
| This diagram is an image of a golfer using a third class lever. |
In golf, using the
golf club adds length to the forearm, which acts to elongate the lever. Due to
the position of the fulcrum, this is known as a third class lever. By
lengthening a third class lever, it increases the speed that can be achieved (Hume, Keogh, & Reid, 2005). The added length from the golf club increases the range of motion of
the levers end, and therefore, its speed. As a result of the added speed
generated, this inturn results in a greater force being generated when the ball
is hit. Therefore, the greater the length of the lever, the additional speed
that can be generated and, therefore, the force that can be applied. The
greater the force being applied to the golf ball, the further the ball will
travel.
However, the golfers
cannot simply have huge golf clubs as it would be too heavy to swing and
accuracy and control would be lost. As the length of the golf club is set, in
order to ensure maximum lever length is achieved, the golfer should have their
arms straightened and wrists uncocked at impact in order to maximise distance (Hume, Keogh, & Reid, 2005).
 |
This image highlights the cocking and un-cocking of the wrists during the golf drive.
|
Sweet spot:
During the golf drive,
hitting the sweet spot of the ball is necessary in order to maximise accuracy
and force (Smith, 2000). Hitting the ball in the middle of the clubface, is the ideal point of
contact because the momentum is not lost from the club head moving and
vibrating (Carello, Thuot, Andersen, & Turvey, 1999). Therefore, maximum momentum is transferred
into the ball therefore resulting in optimal distance.
 |
| Diagram highlights the ideal ‘sweet spot’ to hit the ball in order to maximise distance. |
Projectile motion:
In golf, the
projectile is the golf ball and when the ball is launched it follows a bath
called the trajectory (Blazevich,
2010). The trajectory of a golf
ball is affected by external forces such as, gravity and air resistance, which
are out of the control of the golfer (Blazevich, 2010).
Therefore, there are factors that such as angle, height and speed of release
that can be controlled and improved to maximise distance.
Angle of release:
Projectiles have two types of velocity, horizontal and vertical velocity
(Daly, Kaspriske & Smith, 2002). An objects horizontal velocity remains the
same once released and continues in a horizontal line until it’s overcome by
the vertical forces of gravity. (Ackland, Elliot
& Bloomfield, 2008).
In order to maximise
distance in a golf shot, the optimal angle of release must be established. If
the ball is hit straight up into the air it will have a long flight time but
travel only a very small distance (Blazevich, 2010).
If the golf shot is hit low, it will go further but its flight time would be
short (Blazevich,
2010). Therefore, in most sports
it has been established that the optimal angle of release is 45 degrees because
it is an even combination of both horizontal and vertical flight (Blazevich, 2010).
However, in golf the optimal angle of release is closer to 12-13 degrees
(Winfield & Tan,
2000). The reason for this is because
unlike projectiles in theory, a golf ball has to contend with wind resistance.
Furthermore, the golf club imparts a large amount of backspin on the ball; this
backspin works against the force of gravity and increases the time the ball
spends in the air. Due to this added vertical component, the optimal launch
angle is much lower then 45 degrees. Together this increased horizontal velocity
and increased flight time due to the spin, results in optimal ball displacement.
 |
| Diagram describes the affect of different degrees of spin on the ball. |
Height of release:
During the
golf drive the height of release is less important as the ball is set off a
tee. However, when the tee shots height of release is greater than the height
of landing (elevated tee block), the optimal angle of release changes to less
then 45 degrees (Ackland, Elliot & Bloomfield, 2008). Similarly when the height of release is less then the height of
landing (uphill fairway), the optimal angle is more than 45 degrees (Ackland,
Elliot & Bloomfield, 2008).
Therefore, it is important to change the angle of release depending on the
height, in order to maximise the distance the ball travels.
Speed of release:
Once a golf ball is
hit, its horizontal velocity remains the same during its flight (Ackland, Elliot & Bloomfield, 2008).
Therefore, it is imperative to exert as much force as possible to generate
optimal speed during the shot. The greater the force, the greater the velocity
and therefore overall distance the ball will travel (Blazevich, 2010). In order to maximise distance, the speed of
release is vital.
Assuming the golfer
hits the ball in the sweet spot, and at the optimal angle of release, maximum
distance will be achieved by transferring maximum moment of the ball and consequently
achieving the highest possible speed of release. This can be achieved by establishing
maximum club head speed (Chu, Y., Sell, T. & Lephart. (2010).). Maximum club head speed is produced by the
above-mentioned biomechanics of the golf swing including, lag, lever length,
ground reaction force and maintaining balance and stability. By optimising
these parameters and maximising club head speed, transfer of momentum and speed
of release is ultimately maximised resulting in optimal distance.
“How else we can use this information”
The
biomechanical principals of the golf drive can be applied to many other sports.
In particular sports that involve hitting an object. The main biomechanics of
the golf drive are balance and stability, ground reaction force, summation of forces, momentum and impulse, levers,
sweet spots and projectile motion principals. It is these biomechanical
principals that enable an athlete to improve the distance an object can travel.
The biomechanics investigated included both principals behind the athletes’
movement, the equipment and finally contact with the object. The knowledge
gained from biomechanics can help athletes understand and improve their
movements.
Knowledge of such biomechanics
is also very important for teachers and coaches in order to explain to their student’s
specific movements. Knowledge of biomechanics allows these professionals to identify
movements that need to be changed in order to improve actions. Biomechanical
understanding can be used in a number of ways to improve performance,
rehabilitation, prevent injury and achieve sport mastery.
“References”
Ackland, T., Elliot, B & Bloomfield, J. (2008). Applied Anatomy and Biomechanics in Sport).Human
Kinetics Publishers.
Blazevich, A. (2010). Sports biomechanics, the basics:
Optimising human performance. A&C Black.
Bradshaw, E., Keogh,
J., Hume, P, Maulder, P., Nortje, J. & Marnewick, M. (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. 80
(2), 185-197.
Carello, C.,
Thuot, S., Andersen, K. L., and Turvey, M. T. (1999). Perceiving the sweet
spot. Perception, 28, pp. 1128-1141.
Chu, Y., Sell, T. & Lephart. (2010). The
relationship between biomechanical variables and driving performance during the
golf swing. Journal of sports sciences,
28 (11) 1251-1259).
Cochran, A., Crews, d.,
Farrally, M., Price, R. & Snow, J. (2003). Golf science reseach at the
beginning of the twenty-first century. Journal
of Sports Sciences, 21 (9), 753-765.
Daly, J., Kaspriske, R. & Smith, R. (2002). Drive, Chip
& Putt : How to play and practice golf's three most important strokes. Golf Digest, 53(6), 84.
Goehl, C. (2002). A simplified approach for teaching
golf to beginners. The Journal of
Physical Education, Recreation & Dance, 73, 12-13.
Hume, P., Keogh,
J. & Reid, D. (2005) The role of biomechanics in maximizing distance and
accuracy of golf shots. Sports Medicine, 35
(5), 429-249.
Kenny, I., McCloy, A.,
Wallance, E. & Otto, S. (2008). Segmental sequencing of kinetic energy in a
computer-simulated golf swing. Sport
Engineering, 11 (1), 37-45.
Smith, M. (2010). The
role of physiology in the development of golf performance. Sports Medicine, 40, 635.
Smith, S. (2000) from
the Golf digest labs: Hitting the sweet spot. Golf Digest, 51 (8), 25.
Winfield, D.
& Tan, T. (2000). Optimization of club-head loft and swing elevation angles
for maximum distance of the golf drive. Department
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