Abstract:
A method of analyzing and practicing golf strokes, such as putting strokes, is provided. A surface is provided, wherein a golfer can practice one or more strokes in an environment simulating components of a golf course, such as a green. A club movement detector embedded in the surface and comprising a plurality of photodetectors and associated circuitry determines the position and velocity of the club face. A head movement sensor detects rotational movement of the golfer&#39;s head during the golf stroke. An eye movement sensor detects movement of the eyes of the golfer during the golf stroke. A processor connected to the club movement sensor, eye movement sensor, and head movements sensor gathers movement data during the golf stroke and produces measurements corresponding to the golf stroke, such as eye, head, and club movement of the golfer. The measurements can be compared with those of professional golfers to determine the efficiency and accuracy of the putting stroke.

Description:
SPECIFICATION  
     RELATED APPLICATIONS  
       [0001]    The present invention claims the benefit of U.S. Provisional Application Serial No. 60/296,527 filed Jun. 7, 2001, and U.S. Provisional Application Serial No. 60/317,944 filed Sep. 7, 2001, the entire disclosures of which are both expressly incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a method and apparatus for golf stroke analysis, and more particularly, to a method and apparatus for analyzing components of a golf stroke including club face movement and the physical movement of a golfer during a stroke. The present invention also relates to a method and apparatus for allowing golfers to practice and improve their golf strokes.  
           [0004]    2. Related Art  
           [0005]    In the field of sports, generally, and in the game of golf, particularly, there has been an increasing need to address specific questions posed by athletes concerning the body&#39;s forces and motions during athletic activities. Much information has been acquired about the golf swing and the physical forces associated therewith, including forces impacting the golf ball. Such information has been obtained using high-speed photography and videotape, and the components of the golf swing have been studied in great detail during, at least, the past 50 years. Unfortunately, such methodologies do not allow for real-time analysis of a golfers&#39; stroke.  
           [0006]    The putting stroke is a crucial element in the game of golf. Statistics compiled by the Professional Golfer&#39;s Association show that approximately 40% of the total strokes by professional golfers in a given round are spent on putting. Golf teaching professionals and sports psychologists frequently teach beginning and experienced golfers the importance of minimal or no eye and head movements throughout the putting stroke. Reduced eye movement is particularly important to successful execution of the putting stroke, because eye fixation at locations other than the ball can cause improper strokes and missed puts. Further, reduced head movement allows a golfer to maintain a stable image of a putting surface, thereby enhancing the golfer&#39;s accuracy at putting. If the golfer&#39;s head moves during the stroke, putting misalignment and missed putts can result. Additionally, putter head velocity and acceleration, in conjunction with a golfer&#39;s grip, are useful indicators of a golfer&#39;s putting accuracy and ability.  
           [0007]    What would be desirable, but has not yet been provided, is a system for analyzing the aforementioned aspects of a golfer&#39;s putting stroke, and producing real-time results indicating the effectiveness and accuracy of the putting stroke, and for allowing golfers to practice their strokes while also receiving feedback information.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0008]    It is an object of the present invention to provide a method and apparatus for analyzing golf strokes.  
           [0009]    It is another object of the present invention to provide a method and apparatus for analyzing putting strokes.  
           [0010]    It is an additional object of the present invention to provide a method and apparatus for allowing a golfer to practice and improve his or her golf stroke, while receiving feedback thereon and allowing for the comparison of measurements of the swing to measurements of a professional golfer&#39;s swing.  
           [0011]    It is a further object of the present invention to provide a method and apparatus for measuring eye, head, and club movement during a golf stroke, including a putting stroke.  
           [0012]    It is an additional object of the present invention to provide a method and apparatus for analyzing a golf stroke including a club movement sensor for measuring club movement.  
           [0013]    It is still another object of the present invention to provide a method and apparatus for analyzing a golf stroke including a head movement sensor for measuring head movements during the stroke.  
           [0014]    It is a further object of the present invention to provide a method and apparatus for analyzing a golf stroke including an eye movement sensor for measuring eye movements during the stroke.  
           [0015]    It is another object of the present invention to provide a method and apparatus for analyzing a golf stroke including a processor for acquiring eye, head, and club movement data and processing same.  
           [0016]    It is still another object of the present invention to provide a method and apparatus for comparing eye, head, and club movement data of a golfer to eye, head, and club movement data of golfers of various experience levels.  
           [0017]    It is yet another object of the present invention to provide a method and apparatus for determining the effect of different golf grips on eye, head, and club movement during a golf stroke, including a putting stroke.  
           [0018]    The present invention relates to a method and apparatus for analyzing and practicing a golf stroke, particularly a golf putting stroke. A putting platform is provided, wherein a golfer can putt in an environment simulating a golf green. Information regarding the golfer&#39;s eye, head, and club movements during the putting stroke are acquired using a plurality of sensing devices. A club movement sensor in the putting surface measures club movements during the stroke, without requiring attachment to the club. Eye movement sensors measure left and right eye movements of the golfer during putting. A head movement sensor tracks rotational movement of the golfer&#39;s head during the putting strokes. The acquired motion data are gathered simultaneously by a processor, and time traces of club, head, and eye movement may be generated. The time traces can be compared to time traces of golfers of various experience levels to determine the accuracy and efficiency of the golfer&#39;s putting stroke. Additionally, the effect of various golfing grips on eye, head, and club movement can be measured and analyzed. As such, a golfer can practice and improve his or her golf stroke, and compare measurements thereof to measurements of others, such as professionals.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    Other important objects and features of the invention will be apparent from the following Detailed Description of the Invention taken in connection with the accompanying drawings in which:  
         [0020]    [0020]FIG. 1 is a perspective view of the apparatus of the present invention during use by a golfer.  
         [0021]    [0021]FIG. 2 a  is a top view of the club movement sensor shown in FIG. 1.  
         [0022]    [0022]FIG. 2 b  is a side view of the club movement sensor and a portion of the putting surface shown in FIG. 1.  
         [0023]    [0023]FIG. 2 c  is an end view of the club movement sensor and a portion of the putting surface shown in FIG. 1.  
         [0024]    [0024]FIG. 3 is a perspective view of an embodiment of the head movement sensor shown in FIG. 1.  
         [0025]    [0025]FIG. 4 a  is a side view of the eye movement sensor shown in FIG. 1.  
         [0026]    [0026]FIG. 4 b  is a side view showing the eye movement sensor of FIG. 1 shown in greater detail.  
         [0027]    [0027]FIG. 5 is a block diagram showing components of the present invention.  
         [0028]    [0028]FIG. 6 is a schematic diagram showing a circuit configuration of the club movement sensor of the present invention.  
         [0029]    [0029]FIG. 7 is a diagram showing operation of the club movement sensor.  
         [0030]    [0030]FIG. 8 is a graph showing a time trace of club movement during a putting stroke.  
         [0031]    [0031]FIG. 9 is a graph showing a time trace of eye movement during a putting stroke.  
         [0032]    [0032]FIG. 10 is a graph showing a time trace of head movement during a putting stroke.  
         [0033]    [0033]FIG. 11 a  is a graph showing a time trace of club movement of an experienced golfer during a putting stroke.  
         [0034]    [0034]FIG. 11 b  is a graph showing a time trace of club movement of a novice golfer during a putting stroke.  
         [0035]    [0035]FIG. 12 is a graph showing simultaneous time traces of eye, head, and club movement during a putting stroke.  
         [0036]    [0036]FIG. 13 a  is a graph showing simultaneous time traces of eye, head, and club movement of a novice golfer during a putting stroke.  
         [0037]    [0037]FIG. 13 b  is a graph showing simultaneous time traces of eye, head, and club movement of an experienced golfer during a putting stroke.  
         [0038]    [0038]FIG. 14 is a graph showing time traces of eye, head, and club movement when a conventional golf grip is used during a putting stroke.  
         [0039]    [0039]FIG. 15 is a graph showing time traces of eye, head, and club movement when a cross-handed golf grip is used during a putting stroke.  
         [0040]    [0040]FIG. 16 is a graph showing time traces of eye, head, and club movement when a one-handed golf grip is used during a putting stroke.  
         [0041]    [0041]FIG. 17 is a table showing results of statistical analysis of conventional, cross-hand, and one-handed grips used during 3 foot and 9 foot putts.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0042]    The present invention relates to a method and apparatus for analyzing golf strokes, particularly a putting stroke. A variety of physical movements can be tracked and analyzed during the golf stroke, such as eye, head, and club movement, and time traces thereof can be produced in real time. The sampled data can be compared with pre-recorded time traces of golfers at different experience levels, to determine the accuracy and efficiency of the golfer&#39;s stroke. Further, the effects of various golf grips on eye, head, and club movement can be determined. A golfer can practice and improve his or her game, and compare measurements relating to his or her golf stroke to measurements of professionals.  
         [0043]    [0043]FIG. 1 is a perspective view of an embodiment of the present invention. The system of the present invention comprises a variety of components which, operating in conjunction, provide golf stroke analysis. A putting surface  80  is provided for a golfer  20  for taking practice putting strokes using any club  30  and golf ball  34  known in the art. Movement of club  30  along a path generally indicated by line  32  can be analyzed by club movement sensor  60 , embedded in putting surface  80 , as will be hereinafter further described. Importantly, club movement sensor  60  does not obstruct the path of golf ball  34 , allowing golfer  20  to putt normally and (hopefully) sink golf ball  34  into hole  82 . Further, putting movement sensor  60  allows for the analysis of movement of club  30 , without requiring the attachment of any apparatus thereto.  
         [0044]    In an embodiment of the present invention, putting surface  80  can be partitioned into two or more surfaces that can be positioned lengthwise to allow for putts of varying lengths. For example, two sections of putting surface  80  can be joined to allow for putts of three feet in length, additional sections can be added to allow for putts of nine feet in length. Any combination of sections of putting surface  80  can provided for allowing putts of any desired length.  
         [0045]    Movement of the head of golfer  20  during the putting stroke can also be measured by the present invention. Rotational movement of the head of golfer  20 , indicated generally along axis  24 , can be measured by head movement sensor  40 , attached to helmet  41 , as will be hereinafter further described. It is to be understood that other types of head movement (i.e., side-to-side) are contemplated by the present invention and considered within the scope thereof. Head movement sensor  40  can be any sensor known in the art, e.g., an accelerometer with wireless transmitter and receiver, that is capable of measuring rotational movement.  
         [0046]    Eye movements of golfer  20  can also be analyzed by the present invention by eye movement sensor  50 , as will be hereinafter further described. In a preferred embodiment, eye movement sensor  50  is an infrared device that tracks motion of both right and left eyes of a golfer. Other eye movement sensors are considered within the scope of the invention.  
         [0047]    Movement data generated by eye movement sensor  50 , head movement sensor  40 , and club movement sensor  60 , is transmitted to processor  70  by cables  72 . It is conceivable that other means for transmitting the acquired data, such as radio frequency (“RF”) or infrared (“IR”) transmission, can be utilized to channel the acquired movement data to processor  70 . The movement information gathered by processor  70  during a putting stroke can then be analyzed to determine the accuracy and efficiency of the putting stroke.  
         [0048]    [0048]FIG. 2 a  is a top view of the club movement sensor of the present invention. Putting motion sensor  60  comprises first detector array  62 , and second detector array  64 , each of the detectors having a plurality of detectors  66 . In a preferred embodiment of the invention, detectors  66  are infrared phototransistors. As a club moves along axis  32 , shadows are cast on one or more of the detectors  66 , whereupon the one or more detectors  66  turn electrically off. The outputs of detectors  66  of both first detector array  62  and second detector array  64  are then fed to processor  70  via cables  72 . The second detector array  64  is positioned to track movement of the club to impact. Thereafter, the first detector array  62  is positioned to track movement of the putter after impact. The first detector array  62  is offset from the second detector array  64 , so that golf ball  34  can travel freely along path  36  without traveling over detectors  66  of first detector array  62 . Other spatial configurations of club movement sensor  60 , first detector array  62 , and second detector array  64  are considered within the scope of the present invention.  
         [0049]    [0049]FIG. 2 b  is a side view of the club movement sensor  60  and putting surface  80  of the present invention. In a preferred embodiment of the present invention, detectors  66  are positioned at increasing intervals away from the ball  34 , in both frontward and rearward directions. For example, the first four detectors  66  of first detector array  62  and second detector array  64 , closest to ball  34 , are spaced approximately ½ inch apart. The next two detectors are spaced 1 inch apart. The remaining two detectors are then spaced 2 inches apart. It is to be understood that additional detectors and other spatial arrangements are considered within the scope of the present invention.  
         [0050]    [0050]FIG. 2 c  is an end view of the club movement sensor  60  and putting surface  80  of the present invention. The surface  80  can be constructed of wood boards  82 ,  84 , and  86 , such as particle boards, which are joined together and covered with artificial grass to form putting surface  80 . Other materials capable of forming putting surface  80  are considered within the scope of the present invention. Putting surface  80  contains cavities for retaining embedded detector arrays  62  and  64 .  
         [0051]    [0051]FIG. 3 is a perspective view of the head movement sensor of the present invention. Rotational movement of a golfer&#39;s head about axis  24  can be measured during a putting stroke by sensor  44 . A golfer wears hat or helmet  41  which transfers rotational movement of the golfer&#39;s head to sensor  44 , via interconnections  42  and  43 . Interconnections  42  and  43  are designed to mate interchangeably, and allow a user to step away from sensor  44  to disengage therefrom. It may be desirable to magnetize these components to facilitate engagement thereof. Interconnection  42  is attached to hat or helmet  41 , and interconnection  43  is attached to sensor  44 . Sensor  44  can be any sensor in the art that is capable of measuring rotational movement, such as a potentiomenter. According to an embodiment of the invention, sensor  44  is mounted via pivot  45  to a fixed surface, and output from sensor  44  is transmitted via cables  72 . It is to be understood that various other configurations are considered within the scope of the invention. For example, sensor  44  could be mounted on the hat or helmet  41 , and could be self-contained, i.e., not attached to a fixed surface. The sensor could contain a pendulum such that when one rotates his or her head, a reading is taken. Further, this reading could be wirelessly transmitted to the processor. Additionally, other headgear can be used to receive the golfer&#39;s head and transfer movement thereof to a sensor.  
         [0052]    [0052]FIG. 4 a  is a side view of the eye movement sensor  50  of the present invention. Eye movement sensor  50  can be any sensor known in the art that is capable of measuring eye movements, such as a Skalar-Iris Model 6500 helmet-mounted infrared reflection device. Other comparable detection devices can be used with the present invention without departing from the scope thereof. In a preferred embodiment, eye motion sensor  50  contains one or more infrared detectors  52  that are pointed generally in the direction of the golfer&#39;s eyes and measure eye motion of the golfer (i.e., left-to-right and right-to-left eye motion). Output from the one or more infrared detectors  52  can be sent to a processor via cables  72 , or wirelessly. Optionally, eye motion sensor  50  can be affixed to hat or helmet  41  via frame  54 , or formed integrally therewith. Alternatively, the sensors can be incorporated on eyewear. Preferably, hat or helmet  41  and eye motion sensor  50  are manufactured to be lightweight, so that a golfer experiences minimal to no discomfort while wearing same during a golf stroke.  
         [0053]    [0053]FIG. 4 b  is a side view showing the eye movement sensor  50  of the present invention shown in greater detail. Movements of a golfer&#39;s eyes, such as eye  26 , can be tracked by infrared detectors  52 . In a preferred embodiment of the present invention, infrared detectors  52  of eye movement sensor  50  have a linear range of +/−25 degrees, a combined resolution of 5 minutes of arc, and a bandwidth of 200 Hz, but these tolerances are not required. Voltage output signals of eye movement sensor  50  represent eye movements of the golfer&#39;s eyes, and can be analyzed by a processor.  
         [0054]    [0054]FIG. 5 is a block diagram showing component parts of the present invention. Outputs from the head movement sensor  40  and eye movement sensor  50  are connected to analog-to-digital (A/D) converters  90  and  92 , respectively. Club movement sensor  60  is connected to digital input port  94 . The resulting digital signals derived from each of the sensors  40 ,  50 , and  60  are then processed in real time by processor  70 . Processor  70  can be any computer system known in the art. In a preferred embodiment of the present invention, processor  70  acquires the digitized movement data from each of the sensors, and outputs same. Such output may comprise synchronized time trace plots indicating movement of the right eye, left eye, club, and head of the golfer. As shown in FIG. 5, such data can be output through numerous channels (i.e., channels  1  through  4 ) for presentation to the golfer or for further data processing.  
         [0055]    [0055]FIG. 6 is a schematic diagram showing an example of a circuit configuration of the club movement sensor  60  of the present invention. A plurality of infrared sensors, such as phototransistors Q 1  through Q n , can be connected to provide club movement detection. For purposes of illustration, only phototransistors Q 1  through Q 4  are shown connected in the circuit of FIG. 6. Further, other light-sensing devices, such as CdS photocells, can be used in place of the phototransistors. Each of phototransistors Q 1  through Q 4  are connected to difference amplifiers D 1  through D 4 , which reduce noise in the signals generated by each of phototransistors Q 1  through Q 4 . Further, difference amplifiers D 1  through D 4  allow for the generation of an electrical signal corresponding to the leading edge (i.e., face) of a club passed over one or more of phototransistors Q 1  through Q 4 . Connected to difference amplifiers D 1  through D 4  are comparators C 1  through C 4 , which compare the outputs of each of difference amplifiers D 1  through D 4  to a threshold voltage V T . It is to be understood that other circuit configurations of club movement sensor  60  not depicted in FIG. 6 are considered within the scope of the present invention. In a preferred embodiment of the invention, 16 phototransistors are provided in club movement sensor  60  to produce a 16 bit digital signal in which one of the bits indicates the position of the club face.  
         [0056]    [0056]FIG. 7 is a diagram showing operation of the club movement sensor  60 . Club  30 , having a face  31 , is passed over phototransistors of the club movement sensor  60 , shown illustratively as Q 1  through Q 4 , generally along path  32  of a putting stroke. At a given point along the path  32  of the putting stroke, club  30  casts a shadow over one or more of the phototransistors of club movement sensor  60 , turning same electrically off. As shown, club  30  casts a shadow over phototransistors Q 2  and Q 3 , turning them to an off state, while phototransistors Q 1  and Q 4  remain in an electrically on state. In an illustrative embodiment, the on state of the phototransistors is indicated as a voltage of 0 volts, while the off state is indicated as a voltage of +5 volts.  
         [0057]    Voltage outputs from each of phototransistors Q 1  and Q 4  are then sent to difference amplifiers D 1  through D 4 , wherein outputs from two of the phototransistors are processed by each of the difference amplifiers. When the input voltage of a first phototransistor connected to one of the difference amplifiers is lower than the input voltage of the second phototransistor, a negative voltage is produced. Conversely, when the input voltage of the first phototransistor is lower than the input voltage of the second phototransistor, a positive voltage is produced. Further, when the input voltages of the phototransistors are equal, zero voltage is produced. Thus, as shown in the illustrative embodiment of FIG. 7, voltage of zero produced by Q 1  and a voltage of +5 volts produced by Q 2  cause difference amplifier D 1  to emit a voltage of −5 volts.  
         [0058]    Outputs from each of the difference amplifiers D 1  through D 4  are then sent to comparators C 1  through C 4 , and are compared thereby to a threshold voltage V T . In a preferred embodiment of the present invention, V T  is 0.7 volts. Other values can be substituted for V T . For input voltages that fall below V T , a negative voltage (i.e., −12 volts) is produced. Conversely, for input voltages that exceed V T , a positive voltage (i.e., +5 volts) is produced. Thus, as shown in FIG. 7, a voltage of −5 volts provided by difference amplifier D q , which is lower than V T  of −0.7 volts, an output voltage of −12 volts is produced by comparator C 1 . Accordingly, the position of face  31  of club  30  can be indicated by a single positive voltage produced by one of the comparators. Therefore, a voltage of +5 volts produced by comparator C 3  indicates the position of club face  31  amongst the plurality of phototransistors.  
         [0059]    Outputs from the sensors of the present invention can be utilized to produce time traces corresponding to eye, club, and head movements. In a preferred embodiment of the invention, C++ and MATLAB programs are used to generate position and velocity graphs as functions of time for club movement, left eye movement, right eye movement, and head movement. The generated time traces/graphs can then be compared amongst golfers at varying skill levels to indicate the efficiency and accuracy of the subject golfer. It is well known that any general purpose computer, programmed by languages known in the art, can be used to produce the time traces.  
         [0060]    It should be apparent to those skilled in the art that the present invention can be adapted to allow analysis and practice of all types of golf strokes, such as putting, driving strokes, iron stokes, chips, pitches, or other stokes. The apparatus of the present invention can be installed in commercial driving ranges, golf courses, or other practice locations, allowing golfers to quickly gauge the efficiency of their golf strokes and to receive feedback on practice strokes by returning real-time measurements of the strokes and comparing same to measurements of professional golfers. Further, the present invention can be adapted to allow practice and analysis of other sports involving stroke-like movements.  
       EXAMPLE  
       [0061]    The apparatus of the present invention was experimentally tested on twelve volunteers, divided into three groups according to skill levels. Individuals with handicaps between 0 and 9 were placed in the first group, and individuals with handicaps between 10 and 20 were placed into the second group. Novices were placed into the third group. Each group had four volunteers. Each subject made twenty 3-foot putts and twenty 9-foot putts using the present invention, and results for each of the volunteers were compared. It was found that the typical low-handicapper exhibited a small head rotation (i.e., clockwise as seen from top) during the backstroke, compensated for by a smooth eye movement (i.e., vestibulo-ocular reflex), wherein steady eye fixation on the ball was maintained. Head rotation appeared to be associated with a slight shoulder turn during the putting stroke, and occurred less frequently for 3-foot putts but occasionally appeared for 9-foot putts. The typical mid-handicapper demonstrated a similar response pattern, but additionally exhibited saccadic eye movements (i.e., fast jumps in fixation) during the backstroke and at the time of impact. The typical novice golfer showed relatively large head rotations and compensatory eye movements, and exhibited frequent erratic eye fixations through the backstroke and during impact.  
         [0062]    [0062]FIGS. 8 through 10 are graphs showing examples of measurements of club, eye, and head movement achieved by the present invention. FIG. 8 is a graph showing time traces of club movement during a putting stroke produced by the present invention. Club position, measured in centimeters, is graphed as a function of time, measured in seconds. Positive and negative club position values indicate movements toward or away from the hole, respectively. Position of the club is represented as a solid line, while velocity of the club is represented as a dashed line. The point of impact with the ball is illustratively represented as a club position value of 0, occurring between 1 and 1.5 seconds.  
         [0063]    [0063]FIG. 9 is a graph showing time traces of eye movement during a putting stroke. Eye movements for both left and right eyes of the subject are indicated in the top and bottom graphs, respectively. Prior to capturing eye movement data, the subject fixated on three known locations (i.e., left end, middle, and right end of the club movement sensor  60  of the present invention), in order to provide adequate calibration data. Eye movement data acquired during the putt was then measured with reference to the calibration data, and eye position was recorded as displacement in centimeters of the left and right eyes along putting surface  80 . The solid line of the graph indicates eye displacement in centimeters. Further, the dashed line indicates eye velocity.  
         [0064]    [0064]FIG. 10 is a graph showing a time trace of head movement during a putting stroke. Prior to acquiring head movement data, the head movement sensor  60  was pre-calibrated to provide conversion from a measured voltage change to a corresponding angular rotation of the potentiometer shaft, which in turn corresponded to an angular rotation of the subject&#39;s head. This angle was then converted to a displacement of a hypothetical beam emanating from the center of rotation of the head, approximated by the position of the center between the two eyes of the subject, and measured in centimeters. As shown in the graph, head position is measured in centimeters from the center position of the head, and indicated as a solid line. The dashed line indicates head velocity.  
         [0065]    [0065]FIG. 11 a  is a graph showing a time trace of club movement of an experienced golfer during a putting stroke. As can be seen, club movement is relatively smooth, with backward and forward movement being relatively uniform. These results can be compared to FIG. 11 b , which shows a time trace of club movement of a novice golfer during a putting stroke. Backward movement is noticeably larger than forward movement, and there is a lack of uniformity between forward and backward movements.  
         [0066]    [0066]FIG. 12 is a graph showing simultaneous time traces of eye, head, and club movement during a putting stroke. The dotted line across the four graphs indicates the moment in time in which the ball is struck. Thus, using the present invention, real-time plots of head, club, and eye movement can be generated simultaneously and compared.  
         [0067]    [0067]FIG. 13 a  is a graph showing simultaneous time traces of eye, head, and club movement of a novice golfer during a putting stroke. The point of contact between the club face and the ball is represented in the graphs as occurring after 2 seconds. As can be seen from the graphs, a considerable amount of eye movement for both the left and right eyes of the subject occurred prior to the point of contact. Further, forward and backward club movements are not uniform, as there is greater backward movement than forward movement. Additionally, the occurrence of saccadic eye movement can be seen occurring prior to the putt.  
         [0068]    [0068]FIG. 13 b  is a graph showing simultaneous time traces of eye, head, and club movement of an experienced golfer during a putting stroke. As can be seen, club, eye, and head movements for the experienced golfer appeared more uniform than the movements of the novice golfer, as shown in FIG. 13 a . Club movements are also more uniform, with backward and forward movements being generally equal. Eye movements are significantly less than those of the novice golfer, and saccadic movements do not appear prior to contact between the club face and the ball. Additionally, head movement is reduced.  
         [0069]    The present invention can also be utilized to determine the effect of various golf grips on putting performance. For example, club, eye, and head movements can be measured and compared for various golf grips, i.e., conventional, cross-hand, and single-hand grips. Results using these grips are shown in FIGS.  14 - 16 .  
         [0070]    [0070]FIG. 14 is a graph showing time traces of eye, head, and club movement when a conventional golf grip is used during a putting stroke. Time traces of club, eye, and head movements are shown for a typical 9 foot put using a conventional golf grip. For all traces, position and velocity are indicated by solid and dashed lines, respectively. The vertical dashed lines indicate the duration of the putt starting from the beginning of the backstroke and ending at the point of impact with the ball. FIG. 15 is a graph showing time traces of eye, head, and club movement when a cross-handed golf grip is used during a putting stroke. The same time traces are provided, and show results for the same 9 foot putt. FIG. 16 shows time traces using the one-handed grip.  
         [0071]    The results shown in FIGS.  14 - 16  can be analyzed using statistical methods to determine the effect of the various grips on putting. FIG. 17 shows results of statistical analysis of conventional, cross-hand, and one-handed grips used during 3 feet and 9 feet putts. The results show differences between the putting grips for various parameters, including height to the subject&#39;s eyes, putt amplitude, putt duration, percentage of putts made, and STD of left eye, right eye, and head movements. To determine whether the difference between the results in adjacent columns are significant (i.e., p&lt;0.1; H=1), one-tailed t-tests were performed.  
         [0072]    Height to the subject&#39;s eyes was highest for one-handed grips, intermediate for conventional grips, and lowest for cross-handed grips. This can be attributed to the fact that one-handed subjects tended to stand more erect. Conversely, for cross-handed grips, the left hand is positioned lower on the club grip, thus lowering the left shoulder. Such a result tends to bring the head of the subject down as well, thus lowering the height of the head relative to the platform. The results for this category are the same for 3 and 9 foot putts.  
         [0073]    Putt amplitude is not significantly different for the three putting grip styles for 3 foot putts. However, for 9 foot putts, amplitude for cross-handed grips are statistically significantly smaller than for either conventional or one-handed grips. This may be attributable to a restriction of right elbow motion in the backstroke, as a result of increased bend of the right elbow to compensate for a higher right hand position on the club.  
         [0074]    Putt duration is longer for the one-handed grip than for either conventional or cross-handed grips, for both 3 and 9 foot puffs. This may be due to the increased length of the swing arm (i.e., club plus hand and arm), in the one-handed putt. Hence, if one considers this as a pendulum motion, the increased length corresponds to an increase in the period of motion, resulting, in turn, in an increase in the duration of the putt.  
         [0075]    The percentages of putts made appear to be higher for cross-handed grips than for either conventional or one-handed grips, for both 3 and 9 foot putts. However, such comparisons are not statistically significant, except for 9 foot putts where the percentage made is statistically significantly higher for cross-handed grip than for conventional grip (p=0.006).  
         [0076]    The STD of combined right and left eye movements is lowest for one-handed grips, intermediate for cross-handed grips, and highest for conventional grips, for both 3 and 9 foot putts. The results are all statistically significant except for the comparison between cross-handed and conventional grips for 3 foot putts (p=0.312).  
         [0077]    The STD of head movements is lower for one-handed grips, intermediate for cross-handed grips, and highest for conventional grips, for 3 foot putts. These results are statistically significant except for the comparison between one-handed grips and cross-handed grips (p=0.151). However, for the 9 foot putts, there are no statistically significant differences among the putting grip styles. These findings suggest that head motion plays a more important role in shorter (i.e., 3 foot) putts than for longer (i.e., 9 foot) putts. Further, the results indicate that one-handed grips, and to a lesser extent, cross-handed grips, result in less head motion during the putt.  
         [0078]    Having thus described the invention in detail, it is to be understood that the foregoing description is not intended to limit the spirit and scope thereof. What is desired to be protected by Letters Patent is set forth in the appended claims.