Thirty four women and 146 men volunteered to stroke level and straight putts three and one half meters in length in a controlled environment. The women had an average age of 31 years spanning from 10 to 59 years, an average handicap of 19.6, an average 8 years of experience playing golf, and played an average of 75 rounds per year. The men had an average age of 42 years spanning from 11 to 87 years, an average handicap of 12.3, an average of 22 years of experience playing golf, and played an average of 66 rounds per year.
We used the "Super Sam‟ system to measure and quantify the putting strokes of 180 volunteer golfers. The system is calibrated by aligning the club head square to the intended target line with a laser pointing at the center of the hole and positioned at a 90 degree angle with the clubface. This defines a perfectly square clubface.
Using the same standard length putter, participants performed the following tests:
Test A: Five putts with an uncorrected grip.
Test B: Five putts with a right hand only grip.
Test C: Five putts with a left hand only grip.
Test D: Five putts with an uncorrected grip but without a ball.
Figure 1 visually and graphically displays the rotational characteristics of the putter head of five putting strokes of a top ten ranked PGA Tour Golfer.
The clubface is open 3.6 at the start of the forward swing, closes 4.6 to impact, 7.2 from impact to finish, and closed 8.2 at the end of the forward swing. The clubface rotates shut 3.2 in the 8 inch impact zone before impact and 4.2 after impact. This amount of hand rotation is much higher than the tour average highlighted in gray. This golfer is especially active with the hands during the time of impact.
The left graph traces the alignment of the putter head in degrees relative to the zero target line. The right graph traces the rate of rotation over time. At the beginning of the forward stroke the clubface remains open then gradually closes (the toe of the clubface rotates toward the target relative to the heel). The rate of rotation increases gently until a constant rate is achieved and maintained through impact. At the end of the forward stroke, the rate of rotation decreases, once again, a mirror image of the beginning of the forward stroke. The curves are smooth and show signs of symmetry, herein after referred to as an undisturbed stroke. In 90% of the back strokes measured, the clubface rotated open by at least 3.07 . In 90% of the forward strokes measured, the clubface rotated closed by at least 2.65 before impact and increased to 2.88 after impact.
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The purpose of this research was to identify the key differences between the “normal” putting stroke and the “yips-affected‟ putting stroke. The research was conducted in a controlled environment at the Hank Haney Golf ranch in McKinney, Texas, where 180 golfers volunteered to have their putting strokes measured with the “Super Sam” ultrasound system. Results revealed two types of disturbances present in the putting stroke of 27.22% of the participants. One disturbance was related to the directional control of the putter head during the forward stroke while the other was related to the control of the putter head’s acceleration during the forward stroke. Some participants had both types of disturbances in their putting stroke,some only one. This paper focuses on the directional disturbance observed in the putting strokes of 20.44% of the participants. This disturbance was mathematically identified by a statistical program designed with the SAS software by the authors. When comparing the average rotation curve of ‘yips-affected’ participants to that of the unaffected ones, ‘yips-affected’ participants tend to resist rotation during their forward stroke. With the exception of the ‘yips-affected’ participants who were possibly also affected by medical conditions such as Parkinson’s and intentional tremors, none showed any signs of affliction while performing their practice strokes.
Keywords: Putting, Yips, Directional Yip, Acceleration Yip
Described most frequently as jerks, tremors and spasms affecting mostly the forearms just before the time of impact while putting, the “yips” is believed to be a focal hand dystonia exacerbated by anxiety. First noticed in professions requiring skilled movements such as musicians and surgeons, a focal hand dystonia is classed as a movement disorder along with Parkinson’s disease and is not considered to be psychological in origin. “Yips-affected” golfers (McDaniel, Cummings & Shain, 1989) did not show differences in anxiety level compared to non-affected golfers and reported that the "yips‟ affected other activities than golfing sometimes involving body regions beyond the arms. The “yips” have also been noticed in other sports such as cricket and baseball with similar focal hand dystonia symptoms. The tremors have lately been separated from the following cases:
Freezing: The inability to initiate a desired movement at a specific time and,
Choking: The intended movement program is activated but mainly due to anxiety, such program fails to perform at a desirable level.
Choking seems to be a psychological matter leading to poor performance whereas the "yips‟ seems to be a physical symptom leading to incapacity to perform in any circumstances. In a recent study, the Mayo Clinic used surface EMG electrodes to demonstrate that at 200ms prior to impact, "yips-affected‟ participants ("yippers‟) experienced co-contractions of wrist flexors and extensors (Adler, Crews, Hentz, Smith, & Caviness, 2005). We used a motion capturing device described below to measure the effects of these co-contractions on the movement of the putter head during the putting stroke. We intended to identify the key differences between the disturbed and the undisturbed putting strokes. We found two types of disturbances present in the putting stroke of 27.22% of the participants which we define as follows:
Directional: The inability to control the rotation of the putter head during the forward stroke thereby failing to keep the rate of rotation constant through impact.
Accelerational: The inability to control the acceleration of the putter during the forward stroke thereby failing to keep the rate of acceleration constant through impact.
The purpose of this paper is to illustrate the directional disturbance experienced by "yippers‟ during the putting stroke and define the rotational characteristics of an undisturbed putting stroke.
Figure 2. Disturbed Stroke
Marius Filmalter, Marius Golf, Carrollton, Texas
Pierre-Antoine Noizet, University of Texas at Dallas
Ernst Pöppel, Ludwig Maximilian University of Munich, Germany
B.P.S. Murthi. University of Texas at Dallas.
The graphs in Figure 2 represent the rotational characteristics of the putter head during five disturbed (“yip”) putting strokes. The clubface is opened 4.6° at the beginning of the forward stroke. The initiation of the forward stroke is similar to that of the normal stroke but shortly before impact the pattern changes dramatically. Rotation becomes unpredictable in terms of rate and degrees, closing and opening without any consistency or control. This tendency is herein after referred to as a ‘directional yip’.
Figure 1. Undisturbed Stroke.