Kinematic Sequence

How do different kinematic sequences affect different clubhead speeds?

 

Introduction

Kinematic sequence of a professional golfer

Transition phase of the kinematic sequence

Downswing sequence of a tour professional

Amateur golfer’s kinematic sequence

Conclusion

Bibliography

 

 

How do different kinematic sequences affect clubhead speed?

 

Introduction

 If there is an aspect of a PGA Tour player’s game that inspires a sense of awe and wonder, it is his ability to crush the ball 300 yards or more with such grace and seemingly lack of effort.  The distances these pros are able to achieve (with accuracy as well) can be unfathomable to the average golfer.  It obviously is not a product of sheer size or strength since many pros are small physically yet capable of hitting the golf ball inordinate distances. (Mann, R 1998 p.101)

The distance the golf ball travels is ultimately determined by the speed of the clubhead at impact. (Tinmark et al 2010).  Research has indicated the correct kinematic sequencing of the pelvis, thorax, arms and club can play a significant role in generating clubhead speed (Cheetham 2014, Rose 2013).  The kinematic sequence of golf is similar to other proximal to distal movement patterns and involves the summation of speed principle. (Glazier & Lamb 2013)

The summation of speed principle states that movement patterns with the aim of maximal speed should begin with the larger more proximal muscles initiating the movement and then transferring the force to the smaller more distal muscles with the movement increasing in speed as this occurs. (Bunn 1972)

Using data collected from 3-D motion analysis systems researchers have been able to measure a player’s kinematic sequence and ascertain the efficiency of the golfers swing regardless of their chosen swing style.  (Rose, G 2008)

Figure1.  Shows the speeds reached by the main body segments during the kinematic sequence of a highly skilled golfer.  The kinematic sequence also shows how the summation of speed principle impacts on the golf swing to allow the more distal segments to achieve their greatest velocities at impact.

 

 1173a_kinematicv3
Figure 1. Rotational Kinematic Sequence of a world Class Golfer.  (Cheetham, P.  2018) Rotational Sequence of a World Class Golfer.  Available at http//mytpi.com/biomechanics.  Accessed 3rd January 2018

 

It is important to note that the kinematic sequence happens during the downswing.  (Rose 2013)  From the top of the backswing and into the downswing translation & rotation occurs. (Lynn, S. 2018)   To maximise the golfers ability to create large amounts of rotational speed begins with the player driving their feet into the ground in order to transfer force through the kinetic chain and onto the golf club. (Chu, Y 2010)  Ground reaction forces of up to 2.0 x bodyweight have been observed when hitting long irons and driver. (Hume et al 2005)

Weight is shifted from the trail leg back onto the lead side with the weight distribution being roughly 80/20 in favour of the lead side.  This is then followed by a rapid rotation of the pelvis towards the target accompanied by a triple extension of the ankle, knee and hip of the lead leg to assist with force generation against the ground.  This is immediately followed by a rapid deceleration of the pelvis which then causes the upper torso to accelerate, followed by the arms and then the club with the clubhead making contact with the ball.

This rotational sequence and the lever created at the shoulder and wrist result in the transfer of angular momentum onto the club which is hugely important in regards to producing high clubhead speed. (Cochran & Stobbs, 1968)

 

Kinematic Sequence of a Professional Golfer

Figure 2.  Tour Professional Golf Swing Kinematic Sequence

 

pro sequence
Figure 2.  Tour professional golf swing kinematic sequence is available at http//golfloopy.com/biomechanics.  Golf Swing Kinematic Sequence.   Accessed 3rd January 2018

 

The graph in figure 2 shows angular velocity of the pelvis, chest, lead arm, and the golf club during a typical professional golf swing.  The reader can clearly see that the swing has relatively smooth accelerations and deceleration’s until after impact.

The graph progresses in time from left to right.  Negative rotational speeds indicate movement away from the target in the backswing.  Positive rotational speeds indicate movement toward the target in the downswing.

 

Transition Phase

 The interval between when the purple line (hips) crosses zero to when the blue line (club) crosses zero is the transition phase. The transition phase is the time from when the hips change direction to when the club changes direction

Figure 3.  The transition phase of a tour professional kinematic sequence

Transition_thumb2
Figure 3.  The transition phase of a tour professional kinematic sequence available at http//golfloopy.com/biomechanics.  Golf swing sequencing and timing.  Accessed 3rd January 2018

 

For the first half of the transition, the hips are rotating towards the target while the chest, arms and club are still moving back away from the target.

This rotation of the hips towards the target while the chest is still rotating back, and the fact that the hips keep moving faster than the chest for some time after (until the green curve crosses the purple curve), creates a transitional separation stretch often called the X-Factor.

X-Factor is the amount of coil at the top of backswing and is the difference between shoulder turn and hip turn e.g. 90 degrees of shoulder turn and 50 degrees of hip turn equals a 40 degree X-Factor.  (Cheetham 2013)

The longer the hip line stays above the chest line, the more the X-Factor stretch is increasing.  Research has shown that highly skilled players can create an X-Factor stretch of up to 57˚ compared to 50˚ demonstrated by less skilled players (Glazier & Lamb 2013).

The X-Factor stretch is more important than the X-factor as the golfer is able to generate more power with the large muscles of his core through the utilisation of the stretch-shortening cycle.   (Cheetham 2000)  This same effect happens to each subsequent body segment in the kinetic chain.

Elastic energy in the musculotendinous components is increased with a rapid stretch and then stored, when this movement is immediately followed by a concentric muscle action, the stored elastic energy is released increasing the total force production. (Baechle & Earle 2000, Fletcher et al 2004, Lloyd 2014, McGinnis 1999, Zatsiorsky 2006,)

The reader can see that the chest starts turning back towards the target (the green line goes above zero) half way through the transition, while the lead arm (red line) is still turning back.  The chest then keeps turning faster than the lead arm until well into the downswing (the green line stays above the red line).  This turn of the chest ahead of the lead arm causes the lead arm to horizontally adduct and creates a stretch-shortening cycle at the glenohumeral joint.

Finally, the reader see that the lead arm starts back down while the club is still going back, and stays ahead of the club for a long time, well after the club starts back down at the end of the transition.  The longer that the arm moves faster than the club, the greater the torque that is created on the wrist.

The graph in Figure 2 shows a very small amount of time where the transition phase occurs. If the transition sequence is not performed with precise and specific timing, elastic energy from the muscles and joints is lost. (Lloyd 2014)

pro sequence
Figure 2.  Tour professional golf swing kinematic sequence is available at http//golfloopy.com/biomechanics.  Golf Swing Kinematic Sequence.   Accessed 3rd January 2018

 


Downswing Sequence of a tour professional

 The reader can see that during the tour professional’s downswing, the peak angular velocity for the hips, chest and arm (A, B, and C) are very close in time with each peaking later and faster than the previous segment.

There is a larger interval between the arm peak velocity and the club peak velocity — from C to D which is more than twice as long as from A to C — during which the club more than doubles in speed as the combined energy created by the inner segments is released into the club.

The club rotational speed peaks just after impact which indicates the golfer is transferring maximum force through impact.

 

Amateur Golfers Kinematic Sequence

This paper will compare the following amateur kinematic sequence against the tour professional graph and make conclusions about how these sequences affect clubhead speed.

Figure 4.  Kinematic Sequence of an Amateur Golfer

Amateur sequenceFigure 4. Kinematic Sequence of an Amateur Golfer is available at http//golfloopy.com/biomechanics.  Golf swing sequencing and timing – common faults.  Accessed 3rd January 2018.

 

There are some immediately obvious differences in the amateur kinematic sequence.  Every segment has lower rotational speeds in the downswing.  The peak speeds of each segment are out of sequence, with the arm (C) peaking before the chest (B).  The accelerations and decelerations are also poorer and unstable.

The transition phase is also very short.  Immediately after the transition, the club is rotating faster than the lead arm which would indicate that the golfer is not creating torque on the wrist joint in order to transfer angular momentum onto the club.

There is no deceleration of the chest before impact therefore no torque is created at the shoulder joint.  If there is no torque there is no angular acceleration. (Jorgensen 1999).

The accelerations and decelerations are not smooth in the downswing.  The hips and chest even have a double peak of rotational velocity before impact, indicating a lack of stability and control.  This prevents an efficient transfer of energy along the kinetic chain.

The accelerations of each segment are not evenly spaced, and the peak speeds are not timed correctly, so the golfer is not benefitting from the significant performance benefit provided by stretch-shortening cycle in each segment.

The hips, chest and arms don’t show a rapid deceleration coming into impact, so the angular velocities from these segments are not being transferred out to the golf club.  Indeed, the chest peaks after impact.  Even though the lead arm reaches a peak speed comparable to the professional’s, inefficient energy transfer from the body means that the clubhead speed has decreased considerably.

In contrast, notice the professional graph.  Near the middle portion of the graph, the arm curve (red) is actually on top of the club curve (blue).  This means that the wrist is cocking more just before release, generating torque allowing more angular velocity to be transferred to the club through the efficient use of the stretch-shortening cycle of the forearm muscles.

This satisfies Newton’s third law of motion which states that for every action there is an equal and opposite reaction.  At the beginning of the downswing the hands are moving quicker than the clubhead creating torque on the wrist joint.  Near impact the hands decelerate and transfer momentum to the clubhead that will then accelerate, ultimately leading to high clubhead linear velocity. (Hume et al 2005)

The reader can clearly see that the club speed of the professional at impact is much higher than the amateur.  For whole of the second half of the downswing, until just after impact, the professional’s club is accelerating faster than at any point during amateur’s downswing. The amateurs club reaches peak velocity just before impact and so is decelerating through impact.

 

Conclusion

This paper is of the conclusion that there are many styles of golf swing but there is only one efficient kinematic sequence to maximise clubhead speed.  An important theme that instructors and professionals agree on is that the golfer must possess the appropriate timing of body segments during the downswing (Cheetham et  al 2008, Cochran & Stobbs 1968, Leadbetter 1990, Mann 1998, Rose, G 2008, McClean, J 1996) and utilise the summation of speed principle to maximise clubhead speed at impact. (Cheetham et al 2008)

Highly skilled golfers tend to have different physical characteristics than less proficient golfers (Evans 2015) and given the complexity of the golf swing the golfer may look towards a golf specific strength and conditioning program that includes transverse exercises such as medicine ball training to improve rotational power (Szymanski et al 2007) movement velocity (Ebben et al 1999) and enhance kinematic sequencing.  (Stodden et al 2008)

It has also been shown that better golfers achieve greater speeds and have better kinematic sequences, achieving greater velocities at impact and ultimately greater shot distance.  (Zheng et al 2008).    Amateur golfers do not swing the golf club as effectively as tour professionals and therefore do not hit the golf ball as accurately, consistently or as far.

 

Bibliography

Baechle, T.R., R.W. Earle.  Essentials of Strength Training and Conditioning (3rd Ed.) Human Kinetics.  2000.

Bunn, J W.  Scientific Principles of Coaching (2nd Ed.) Englewood Cliffs.  New Jersey.  1972.

Cheetham, P. Basic Biomechanics for golf.  2014.

Cheetham, P.  The Importance of Stretching The X-Factor In The Downswing of Golf.  2000.

Cheetham, P. The difference between the X-Factor and the X-Factor Stretch.  Available at http//mytpi.com.  Biomechanics.  Last accessed January 2018.

Cheetham PJ, Rose GA, Hinrichs RN, Neal RJ, Mottram RE, Hurrion PD, Vint PF Comparison of kinematic sequence parameters between amateur and professional golfers.  Science and golf V: proceedings of the World scientific congress of golf, Phoenix, United-States.  Crews, D and Lutz, R (Eds).  Energy in Motion.  Mesa Arizona 2008.

Chu, Y et al.  The Relationship between Biomechanical Variables and Driving Performance During the Golf Swing.  (28) 11 2010.

Cochran, A, Stobbs, J.  Search for the Perfect Golf Swing 1968.

Evans, K, Tuttle, N.  Improving Performance in Golf:  Current research and Implications From A Clinical Perspective.  Brazilian Journal Of Applied Physical Therapy.  2015.

Fletcher, I et al.  Effect of an 8-week combined weights and plyometric Training Program On Golf Drive Performance.  Journal of Strength and Conditioning Research. 18(1) 2004.

Glazier, P Lamb P.  The Swing. In: Smith, M. Golf Science.  Ivy Press.  2013.

Hume et al.  The Role of Biomechanics in Maximising distance and Accuracy of Golf Shots, Sports medicine, 35 (5) 2005.

Hume et al.  Evidence for Biomechanics and Motor Learning Research Improving Golf Performance.  Sports Biomechanics, 11 (2) 2012.

Jorgensen, T.P.  The Physics of Golf. (2nd Ed).  Springer Verlag.  1999

Leadbetter, D.  The Golf Swing.  1990.

Lloyd, R.  Strength and Conditioning Considerations for Golf.  Strength and Conditioning journal.  36 (5) 2014.

Lynn, S.  Swing Catalyst online certification course. Available at http//swing catalyst.com.  Kinetics and Kinematics.  Last accessed 3rd January 2018.

Mann, R.   Swing like a pro.  The Breakthrough Scientific Method of Perfecting Your Golf Swing.  1998.

McClean, J.  The X Factor Swing.  Harper Collins. (1st Ed.) 1996

McGinnis, P.M.  Biomechanics of Sport and Exercise. (3rd Ed.) Human Kinetics.  1999.

Rose, G. Kinematic Sequence, TPI Golf Fitness Instructor Manual.  2008

Rose, G.  2013 Kinematic Sequence Basics.  Available at Http//www.mytpi.com. Biomechanics.   Last accessed 3rd January 2018.

Stevenson, G et al.  The journal of UK Strength & Conditioning Association.  Issue 38. September 2015.

Stodden, DF, et al.  A Comparison of trunk Kinematics in Trunk Training Exercises and Throwing.  Journal of Strength and Conditioning Research.  (22) 1 2008.

Szymanski, DJ Et al,  Effect of Twelve Weeks of Medicine Ball Training on High School Baseball Players.  Journal of Strength and Conditioning Research.  (21) 3  2007.

Tinmark et al.  Elite Golfers Kinematic Sequence in Full Swing and Partial Swing Shots.  Sports Biomechanics, 9 (4) 2010.

Zatsiorsky, V, Kraemer, W.  The Science and Practice of Strength Training.  (2nd Ed.)  2006

Zheng et al.  Kinematic Analysis of Swing in Pro and Amateur Golfers.  International Journal of Sports Medicine, 29 (6) 2008.

Http//www.golfloopy.com. Biomechanics.  Last accessed 3rd January 2018.

 

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