An Investigation into the Effect of a Putter with
a Weighted Shaft on Club/Ball Impact

Abstract
This study examines the effect that a weighted putter has on the impact and performance of a golf ball.

Controlling the speed of the putter at impact is vital for distance control and good green reading. Video analysis at 1000 frames per second was used to analyse distance, speed and acceleration of the putter head and ball during the initial stages of putts. A standard weighted 34" length putter was used for the experiment, with and without the additional weight around the mid point of the shaft. Each putter was clamped to a perfectioniser, which simulated the putting action. The putter struck the ball in three different positions - Toe of the club / Sweet Spot / Heel of Putter. Each putt was analysed using Quintic Biomechanics 9.03 software. The 'New Weighted Putter' (NWP) has a lower impact ratio (IR) (peak ball velocity (ms^-1) divided by the impact speed of the club (ms^-1). The range of IR during the NWP is 0.44 (1.41 Toe - 1.85 Sweet Spot). The IR range for the standard putter is 0.51 (1.41 Toe - 1.85 Sweet Spot). The greater this range, the greater the variation in the peak ball velocity and therefore the variation in distance travelled. This study shows that by reducing the impact ratio the NWP increases the size of the sweet spot. If the ball is hit slightly off centre then the ball will retain more of its energy with the NWP than compared with the original putter.

Keywords: Golf Putting; Weighted Shaft, Speed, Impact, Performance.

Introduction

“The putting stroke is only one of several different types of golf swings, yet it accounts for nearly half of all swings made”

43% (Pelz 2000) 45% (Swash 2001)

Putting has been described as a game within a game on numerous occasions. The majority of coaching magazines, manuals, textbooks suggest ‘feel’ as the key to success, along with a ‘good technique’. A good technique is required in order to create the confidence necessary to hole putts. There is no recovery opportunity from bad putting or back luck. Controlling the speed of the putter at impact is vital for distance control and good green reading.

“Every putt is a straight putt – it just depends on how hard you hit the putt as to whether the ball takes the break or not”

Swash (2001)

Because putting is such a significant part of golf, then the type of putter used is crucial. This paper compares the performance of a standard putter (head, shaft and grip) with an identical putter but with a significant weight fixed in the centre of the shaft. The analysis described in this paper compares the performance of two putters under three test conditions (Toe, Sweet Spot and Heel). This report first outline the method used to analyse the two putters. The main findings of the analysis suggest that the putter with the additional weighted shaft has a bigger sweet spot – i.e. if the ball is hit slightly off centre then the ball will retain more of its energy compared with the original putter without the weight.

Method
Two putters were analysed during this study:

Putter 1: Standard weight 34” Face balanced putter
Putter 2: Standard weight 34” Face balanced putter + additional weighted shaft
              (Designed by Tim Winey - See Figure 1a)

During each putt, the putter was clamped to the perfectioniser (See Figure 1b). The putter head was pulled back to a set position each time and released to simulate a 15ft putt. Every effort was made sure to ensure the putter blade was released from the same position – so as to standardise the impact speed of the clubhead.

Figure 1a: NWP designed by Tim Winey.
Figure 1b: Perfectioniser – Designed by Harold Swash (1998)
Figure 1c: Grip of putter attached to the Perfectioniser

For each putter the club and ball impact was filmed for three different types of putt. These were when the ball was hit from the (i) Sweet Spot, (ii) Toe of the Club and (iii) Heel of the Club. Six trials were carried out for each of these conditions.

Data Acquisition and Analysis

Each trial was filmed using a Redlake PCI 2000S High Speed camera. The camera was placed at 90° to the path of the golf ball, level with the putting surface. Figure 2 shows a typical set-up for the experiments.

Digitisation results were obtained for each putter for the three impact positions. Digital video film (1000Hz) was recorded 40ms prior to ball contact and 200ms after ball contact. After processing, the film was analysed using a Sony VAIO PCG-Z1XSP personal computer running Quintic 9.03 video analysis software. Two-dimensional scaling, prior to digitisation was carried out using two-dimensional calibration. All putting strokes were digitised at a rate of 500Hz.

On average ten frames were digitised prior to ball contact and twenty-five frames post ball contact. A four-point model was created for the purpose of the analysis (two points on the club face and two points on the ball). For each frame, the horizontal distance travelled (mm), horizontal velocity (ms^-1) and the horizontal acceleration (ms^-2) were recorded for both the clubhead and ball.

Note: The digitised values for the clubhead and ball were both averaged to reduce experimental error. Figure 3 shows a typical example of the digitisation process.

Statistical Analysis
Descriptive statistics were calculated for the average horizontal distance travelled (mm), horizontal velocity (ms^-1) and the horizontal acceleration (ms^-2) for both the clubhead and ball.

Results and Discussion
Figure 4 gives an example of how the video images are presented within the Quintic (2004) software.

Figure 4 (left): Typical Video Images obtained from Quintic Biomechanics 9.03 Software. Standard putter – sweet spot

Due to the slight variation in the impact velocity of the clubhead throughout the testing phase, it was necessary to compare the impact velocity of the club under both test conditions.

Table 1 shows the average impact velocity of the clubhead for each test condition.

 

Table 1: Averages: Impact Velocity (ms-1) and Peak Ball Velocity (ms-1)

	Heel (n=6)	Sweet Spot (n=6)	Toe (n=6)	Average (n=18)	Peak Ball Velocity Average (n=18)
Standard	1.045	1.012	1.104	1.054	1.674
NWP	0.967	0.813	0.960	0.913	1.413

The average impact speed for the standard putter was higher 1.054 ms^-1 than compared with 0.913 ms^-1 for the NWP. This resulted in an increased peak ball speed of 1.674 ms^-1 compared to 1.413 ms^-1. A ratio was therefore calculated by dividing the peak ball velocity (ms^-1) by the impact speed of the club (ms^-1) to give an impact ratio (IR). The impact ratio can be seen for each test condition in tables 2 and 3. The mean, standard deviation and standard error figures are also presented.

It is interesting to note that for the standard putter, the highest ratio (1.92 ± 0.04) was recorded when contacting the ball from the sweet spot. The NWP ratio during the sweet spot conditions was 1.85 ± 0.04. The impact speed of the putter controls the distance the ball travels and more importantly the line the golfer needs to start the putt to be successful. As a result of this reduced impact ratio (0.07) the same impact velocity with both putters would result in the standard putter hitting the ball further.

Table 2: Standard Putter

	HEEL			SWEET SPOT			TOE
	Impact Speed (ms-1)	Peak Ball Speed (ms-1)	Impact Ratio	Impact Speed (ms-1)	Peak Ball Speed (ms-1)	Impact Ratio	Impact Speed (ms-1)	Peak Ball Speed (ms-1)	Impact Ratio
1	1.091	1.594	1.46	0.931	1.927	2.07	1.198	1.610	1.344
2	1.054	1.499	1.42	1.075	2.001	1.86	1.103	1.503	1.363
3	1.009	1.524	1.51	0.984	1.952	1.98	1.062	1.511	1.422
4	0.984	1.404	1.43	1.046	1.993	1.91	1.095	1.577	1.440
5	0.922	1.425	1.54	1.050	1.911	1.82	1.029	1.519	1.476
6	1.207	1.779	1.47	0.984	1.828	1.86	1.132	1.577	1.393
Mean	1.045	1.537	1.47	1.012	1.935	1.92	1.104	1.550	1.41
± S.D.	0.090	0.125	0.04	0.050	0.058	0.09	0.053	0.040	0.05
± S.E.	0.037	0.051	0.02	0.020	0.024	0.04	0.022	0.016	0.02

 

Table 3: NWP

	HEEL			SWEET SPOT			TOE
	Impact Speed (ms-1)	Peak Ball Speed (ms-1)	Impact Ratio	Impact Speed (ms-1)	Peak Ball Speed (ms-1)	Impact Ratio	Impact Speed (ms-1)	Peak Ball Speed (ms-1)	Impact Ratio
1	0.791	1.190	1.51	0.807	1.421	1.76	1.001	1.359	1.36
2	0.795	1.087	1.37	0.836	1.622	1.94	1.001	1.272	1.27
3	1.062	1.429	1.35	0.803	1.565	1.95	0.906	1.318	1.46
4	0.955	1.429	1.50	0.749	1.338	1.79	1.124	1.561	1.39
5	1.062	1.557	1.47	0.762	1.330	1.75	0.972	1.363	1.40
6	1.136	1.606	1.41	0.918	1.771	1.93	0.758	1.215	1.60
Mean	0.967	1.383	1.43	0.813	1.508	1.85	0.960	1.348	1.41
± S.D.	0.134	0.187	0.06	0.055	0.160	0.09	0.111	0.108	0.10
± S.E.	0.055	0.076	0.03	0.023	0.065	0.04	0.045	0.044	0.04

 

Table 4: Averages: Impact Velocity (ms-1) / Distance (m) / Peak Ball Speed (ms-1)

		Impact velocity (ms-1)	Distance (m) after 0.4secs	Peak Ball Speed (ms-1)	Impact Ratio ± S.E.
Heel	Normal	1.045	0.0549	1.532	1.47 ± 0.02
	New	0.967	0.0517	1.050	1.43 ± 0.03
SS	Normal	1.012	0.0733	1.928	1.92 ± 0.04
	New	0.813	0.0543	1.508	1.85 ± 0.04
Toe	Normal	1.104	0.0495	1.546	1.41 ± 0.04
	New	0.960	0.0567	1.347	1.41 ± 0.04

No difference in the ratio (1.41 ± 0.04) was noted between the two putters when striking the ball out of the ‘Toe’ of the putter. The ratio is considerably lower than that of the sweet spot. It has been commonly suggested by ‘PGA Teaching Professionals’ that striking a putt out of the ‘Toe’ deadens the putt and the ball has a much lower resultant velocity. This fact is substantiated by the data, as the ‘Toe’ has the lowest impact ratio for both test conditions.

A similar pattern can also be observed during the ‘Heel’ strike. However, the NWP has a higher ratio 1.47 ± 0.03 compared with the standard model putter 1.43 ± 0.02.

Graph 1 and 2 highlight the oscillations in speed and acceleration of the clubhead after contacting the ball out of the ‘Toe’ under both test conditions.

Conclusion
The results of this experiment would suggest that the NWP has a lower impact ratio when striking the golf ball from the sweet spot. The range of the IR during the NWP is 0.44 (1.41 Toe - 1.85 Sweet Spot). The IR range for the standard putter is 0.51 (1.41 Toe – 1.92 Sweet Spot). The greater this range, the greater the variation in the peak ball velocity and therefore variation in distance travelled. This wouldn’t be a problem for a golfer, if they struck the putt out of the same point of the putter each time... The impact speed of the putter controls the distance the ball travels AND more importantly the line the golfer needs to start the putt to be successful. By reducing the impact ratio the NWP putter increases the size of the sweet spot of the putter. An increased sweet spot in turn allows the golfer a greater degree of error if they were to misshit the putt. Controlling the speed of the putter at impact is vital for distance control and good green reading.

”Every putt is a straight putt – it just depends on how hard you hit the putt as to whether the ball takes the break or not”

Swash (2001)

Finally, as a professional golfer, feel is vitally important during the putting stroke. By reducing the IR when striking a golf ball out of the sweet spot you increase the feel for the golfer. The same impact velocity with both test conditions will result in the standard putter hitting the ball further. One possible reason for this reduction in IR is due to the additional weight on shaft having a dampening effect and thus reducing the energy transferred via the shaft into the clubhead. Further biomechanical experiments should compare the dynamics of the NWP shaft during impact. Finally the author would recommend further analysis for various putting distances.