Golf club shaft fitting device

Abstract

To switch selection modes in which a shaft to be recommended is selected on the basis of information about a trajectory of a ball, and to support a variety of needs.SOLUTION: A fitting device 200 includes: an acquisition part 201 which acquires first measured value from a swing sensor 100 and second measured value about the trajectory of the golf ball; a calculation part 202 which calculates feature amounts of a plurality of swings on the basis of the first measured value; a first determination part 203 which determines a plurality of shaft indices for identifying specifications of a shaft to be recommended on the basis of the respective swing feature amounts; a kind number discrimination part 204 which discriminates the number of kinds of a plurality of determined shaft indices; a selection mode switch part 205 which switches a shaft selection mode to a first selection mode or a second selection mode on the basis of the second measured value when there are many kinds of shaft indices; and a second determination part 207 which determines a first shaft index for identifying specifications of the shaft to be recommended according to the switched selection mode.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a golf club shaft fitting device and the like. [Background technology]

[0002] The following Patent Documents 1 and 2 propose a shaft fitting method and device for selecting a shaft that matches a golfer based on the golfer's swing. This fitting method includes a step of obtaining measurement values ​​from a sensor attached to a grip by a golf club by receiving means of a computer, and a step of selecting a shaft that matches the golfer by using swing feature quantities obtained from the measurement values ​​by an arithmetic processing means of the computer.

[0003] Furthermore, in Patent Documents 1 and 2, a golfer who requests fitting is asked to test hit a predetermined number of balls (for example, five balls), and the average of the swing feature amounts calculated at each hit is set as the swing feature amount of the golfer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6087132 [Patent Document 2] Patent No. 6911298 Summary of the Invention [Problem to be solved by the invention]

[0005] Golfers (especially average golfers) cannot always make the same swing. In particular, during a round, mishits often occur. Therefore, there is a need among golfers for a shaft that is suitable for a swing when making a mishit, that is, a shaft that can provide a shot with a long distance and little deviation to the left or right, even when making a swing that has previously resulted in a mishit.

[0006] Furthermore, even if the shot is not considered a miss, if there is a certain degree of variability in a golfer's swing, there is also a need for golfers to be able to select from a number of shafts suited to their individual swing.

[0007] The present disclosure has been devised in consideration of the above-described circumstances, and its main purpose is to provide a golf club shaft fitting device or the like that can switch selection modes to select a shaft to be recommended to a golfer based on information regarding the trajectory of a hit golf ball, thereby being able to respond to the diverse needs of golfers. [Means for solving the problem]

[0008] The present disclosure relates to a fitting device for selecting a golf club shaft suitable for a golfer, the fitting device including: an acquisition unit that acquires first measurement values ​​from a swing sensor by making a plurality of swings to hit a golf ball using a golf club equipped with a swing sensor in an environment where a trajectory measurement device is installed, and second measurement values ​​related to the trajectory of the golf ball measured by the trajectory measurement device; a calculation unit that calculates swing feature values ​​for each of the plurality of swings based on the first measurement values; a first determination unit that determines, for each of the swings based on the respective swing feature values, a plurality of shaft indices for identifying specifications of a shaft to be recommended to the golfer; a type number determination unit that determines the number of types of the determined plurality of shaft indices; a selection mode switching unit that, if there are a plurality of types of shaft indices, switches a selection mode for selecting the shaft between a first selection mode and a second selection mode different from the first selection mode based on the second measurement values; and a second determination unit that determines a first shaft index for identifying specifications of a shaft to be recommended to the golfer from the plurality of shaft indices in accordance with the switched selection mode. [Effects of the Invention]

[0009] By adopting the above-described configuration, the golf club shaft fitting device of the present disclosure can provide a golf club shaft fitting device etc. that can meet the diverse needs of golfers. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an overall configuration diagram showing a golf club shaft fitting system according to an embodiment of the present invention; [Figure 2] FIG. 1 is a block diagram of a fitting system according to an embodiment of the present invention. [Figure 3] 1 is a flowchart illustrating an embodiment of a fitting method according to the present embodiment. [Figure 4]10A and 10B are diagrams illustrating the bending behavior of a shaft during a swing. [Figure 5] 10 is a graph showing the relationship between the passage of time during a swing and the angular velocity in the cocking direction. [Figure 6] 10 is a graph showing the relationship between the first to fourth feature amounts and the EI values ​​suitable for each of them. [Figure 7] FIG. [Figure 8] This is a conversion table of EI value to IFC. [Figure 9] FIG. 1 is a block diagram showing a visualization of information obtained from a single swing. [Figure 10] 10 is a flowchart illustrating an example of a procedure for a selection mode switching process. [Figure 11] 10 is a flowchart showing an example of a procedure in a first selection mode. [Figure 12] 10 is a flowchart showing an example of a procedure in a second selection mode. [Figure 13] 10 is an example of a fitting result in the first selection mode displayed on the display unit. [Figure 14] 10 is an example of a fitting result in the second selection mode displayed on the display unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The specific configurations shown in the embodiments and drawings are for the purpose of understanding the contents of the present disclosure, and the present disclosure is not limited to the specific configurations shown. Furthermore, in multiple embodiments, the same or common elements are designated by the same reference numerals throughout the specification, and redundant explanations will be omitted.

[0012] FIG. 1 shows an overall configuration diagram of a golf club shaft fitting system 1 according to the present embodiment. FIG. 2 shows a block configuration diagram of the fitting system 1 according to the present embodiment. The fitting system 1 and fitting method according to the present embodiment measure the swing of a golfer 3 who wishes to be fitted and can select specifications for a shaft 22 of a golf club 2 that are suitable for this swing. Therefore, the fitting system 1 according to the present disclosure proposes a shaft 22 that corresponds to the swing of the golfer 3, and ultimately improves the distance and directionality of the ball hit by the golfer 3.

[0013] As shown in FIGS. 1 and 2, a fitting system 1 of this embodiment includes, for example, a swing sensor 100 that can be attached to a golf club 2, a fitting device 200, a display unit 300, and a trajectory measurement device 400.

[0014] [Golf Clubs] The golf club 2 has, for example, a grip 21, a shaft 22, and a head 23. In this embodiment, a wood-type golf club is shown as the golf club 2. In other embodiments, the golf club 2 may be an iron-type or a putter-type club.

[0015] [Swing sensor] 1, for example, the swing sensor 100 is configured to be attachable to a golf club 2. The swing sensor 100 of this embodiment is detachable from the grip 21 or the shaft 22 of the golf club 2. It is desirable that the swing sensor 100 be configured to be small and lightweight so as not to interfere with the swing motion of the golfer 3.

[0016] The swing sensor 100 of this embodiment can measure a first measurement value, which is a predetermined physical quantity, from the golf club 2 during a swing. As shown in FIG. 2, the swing sensor 100 of this embodiment includes an angular velocity measurement unit 101, and illustrates a case where the first measurement value is the angular velocity of the golf club 2 during a swing. In a preferred embodiment, the swing sensor 100 can measure angular velocity around at least one axis of a three-dimensional local coordinate system associated with the golf club 2. In another embodiment, as described in Patent Document 2, the physical quantity may be the acceleration of the golf club 2 and / or geomagnetism.

[0017] 1, the local coordinate system may have, for example, a z-axis that corresponds to the axial direction of the shaft 22 of the golf club 2, an x-axis that corresponds to the toe-heel direction of the head 23, and a y-axis that corresponds to the direction of the target ball flight at address of the golf club 2. The swing sensor 100 of this embodiment can measure the angular velocity around each of the above three axes during a swing at a predetermined sampling period (for example, 1 millisecond).

[0018] Therefore, when the golfer 3 swings the golf club 2 equipped with the swing sensor 100 to hit the golf ball 4 multiple times, the first measurement value can be measured by the swing sensor 100. The number of swings is not particularly limited as long as it is two or more, but may be preferably three or more, and more preferably five or more.

[0019] As shown in FIG. 2, swing sensor 100 of this embodiment further includes a communication unit 102 for providing the measured first measurement value to fitting device 200. Communication unit 102 is preferably wireless so as not to interfere with the swing motion. In another aspect, communication unit 102 may be wired. Furthermore, swing sensor 100 may include a removable storage medium (not shown) instead of or in addition to communication unit 102. In this case, the first measurement value may be temporarily stored in the storage medium and then imported into fitting device 200 via this storage medium.

[0020] [Ballistic measurement device] The trajectory measurement device 400 can measure second measurement values ​​that are information related to the trajectories of each golf ball 4 hit by multiple swings. The "information related to the trajectory" of the golf ball 4 is data that specifies the motion state of the golf ball 4 hit with a golf club, and includes, for example, first trajectory information and / or second trajectory information.

[0021] The first trajectory information includes information corresponding to or the flight distance of the hit golf ball 4. The flight distance of the golf ball 4 may be a value approximately calculated from information on the flight distance itself as well as various information on the hit golf ball 4 (for example, information on the launch angle, ball speed, amount of backspin, etc.).

[0022] The second trajectory information includes information corresponding to or a lateral deviation of the hit golf ball 4 from a predetermined target flight line. The lateral deviation of the golf ball 4 may be information on the deviation amount itself, or may be a value approximately calculated from various information on the hit golf ball 4 (information on launch angle, ball speed, amount of backspin, amount of sidespin, etc.).

[0023] As shown in FIGS. 1 and 2, the trajectory measurement device 400 is installed, for example, on the opposite side of the target ball flight line from the golfer 3. The trajectory measurement device 400 includes a measurement unit 401 including, for example, a camera and a control device (not shown). The measurement unit 401 can measure a second measurement value by capturing images of the head 23 and the hit golf ball 4 and analyzing the captured image data. The trajectory measurement device 400 can also measure the head speed (hereinafter, sometimes referred to as "HS"), which is the speed at which the head 23 of the golf club 2 strikes the golf ball 4 during a swing. Various commercially available trajectory measurement devices can be used as this trajectory measurement device 400, and a small, portable device such as "SkyTrak" (a registered trademark of SkyTrak, LLC) is suitable.

[0024] As shown in FIG. 2, the trajectory measurement device 400 of this embodiment further includes a communication unit 402 for providing the second measurement value to the fitting device 200. The communication unit 402 of this embodiment is wireless, but it may also be wired using a cable. The trajectory measurement device 400 may also include a removable storage medium (not shown) in place of or in addition to the communication unit 402. In this case, the second measurement value may be imported into the fitting device 200 via the storage medium.

[0025] [Fitting device] The fitting device 200 of this embodiment acquires first and second measurement values ​​from the swing sensor 100 and trajectory measurement device 400, respectively, and executes predetermined processing. The fitting device 200 is, for example, a computer, and can be realized as, among other things, various general-purpose personal computers, tablet computers, smartphones, or even dedicated terminals.

[0026] As shown in FIG. 2, the fitting device 200 includes an acquisition unit 201 that acquires first and second measurement values ​​from the swing sensor 100 and the trajectory measurement device 400, respectively; a calculation unit 202 that calculates swing feature quantities of multiple swings based on the first measurement values; a first determination unit 203 that determines multiple shaft indices for identifying the specifications of the shaft 22 to be recommended to the golfer 3 based on the swing feature quantities; a type number determination unit 204 that determines the number of types of the multiple determined shaft indices; a selection mode switching unit 205 that switches the selection mode for selecting the shaft 22 between a first selection mode and a second selection mode when there are multiple types of shaft indices; and a second determination unit 207 that determines a first shaft index for identifying the specifications of the shaft to be recommended to the golfer from the multiple shaft indices in accordance with the switched selection mode.

[0027] The fitting device 200 of this embodiment further includes a storage unit 210 (described later), an input unit 211, and a control unit 212. The storage unit 210 includes, for example, a non-volatile first storage unit 210A (described in detail later) in which a fitting program and various master data (described later) are stored, and a volatile second storage unit 210B that serves as a working memory. The processing procedure of the fitting program is shown, for example, in the flowchart of FIG. 3.

[0028] The input unit 211 is configured, for example, by a keyboard, a mouse, a virtual keyboard of a tablet, etc. The control unit 212 operates the above-mentioned units in accordance with the above-mentioned programs, and is configured, for example, by a central processor (CPU).

[0029] [Acquisition Department] Acquisition unit 201 is configured to be able to wirelessly communicate with communication unit 102 of swing sensor 100 and communication unit 402 of trajectory measurement device 400. Therefore, acquisition unit 201 can execute the steps of acquiring the first measurement value and the second measurement value measured by swing sensor 100 and trajectory measurement device 400 via communication units 102 and 402, respectively (steps S1 and S2 in FIG. 3). Acquisition unit 201 stores the acquired first measurement value and second measurement value in memory unit 210.

[0030] [Calculation section] The calculation unit 202 can execute a step of calculating a swing feature amount for each of a plurality of swings based on the first measurement value acquired by the acquisition unit 201 (step S3 in FIG. 3). The swing feature amount is a feature amount that quantitatively characterizes the swing motion of the golfer 3. There are no particular limitations on the swing feature amount as long as it is such a feature amount. In this embodiment, the swing feature amount already described in detail in Patent Documents 1 and 2 is adopted. Below, a brief explanation of this swing feature amount will be given.

[0031] Generally, the swing of a golfer 3 progresses through address, top, and impact. During this time, bending occurs in the shaft 22 of the golf club 2 due to the inertia of the head 23. This bending is transmitted from the grip side of the shaft 22 to the tip side during the swing process, from the top to the impact. Figure 4 shows the hands of the golfer 3 and a portion of the shaft 22 during the swing process, from the take-back (top) to the impact. In Figure 4, the portion of the shaft 22 that is most bent is surrounded by an imaginary line.

[0032] In Figure 4, at point 1 when the top of the swing is reached, bending occurs near the grip of the shaft 22. Next, from the transition point to point 2 at the beginning of the downswing, the bending moves slightly toward the tip of the shaft 22. Furthermore, at point 3 when the arms of the golfer 3 become horizontal, the bending moves toward the tip of the shaft 22 rather than the center. Furthermore, at point 4 just before impact, the bending moves to the vicinity of the tip of the shaft 22.

[0033] Considering the change in the bending position of the shaft 22 during the swing as described above, in this embodiment, attention is focused on the angular velocity ωy in the cocking direction during the downswing from near the top to impact as a swing feature. Specifically, attention is focused on the angular velocity ωy at several points in time as the swing progresses. Here, "near the top" of the swing refers to a time period that includes a predetermined time just before the top and a predetermined time just after the top, and specifically refers to a 100 ms time period from -50 ms after the top to +50 ms after the top, for example.

[0034] 5 shows the relationship between the time (s) from address to impact for a certain swing and the angular velocity ωy (deg / s) in the cocking direction of the golf club 2 during the swing. In this embodiment, as shown in FIG. 5, the following four first to fourth feature amounts F1 to F4 are included as swing feature amounts per swing.

[0035] The first feature value F1 is the gradient of the angular velocity ωy in the cocking direction near the top. The first feature value F1 can be calculated, for example, by adding the angular velocity ωy 50 ms before the top and the angular velocity ωy 50 ms after the top. Note that the direction of the angular velocity of the golf club 2 during the swing changes at the top. Therefore, when calculating the sum, the angular velocity before the top is multiplied by a negative value in advance to convert it to a positive value.

[0036] The second feature value F2 is the average value of the angular velocity ωy from the top to the point where the angular velocity ωy reaches its maximum. The second feature value F2 can be calculated by finding the maximum value of the angular velocity ωy from the top to impact, and dividing the cumulative value of the angular velocity ωy from the top to the point where this maximum value is reached by the time from the top to the point where the maximum value is reached.

[0037] The third feature value F3 is the average value of the angular velocity ωy from the time when the angular velocity ωy reaches its maximum until the impact, and can be calculated by dividing the cumulative value of the angular velocity ωy from the time when the angular velocity ωy reaches its maximum until the impact by the time from the time when the angular velocity ωy reaches its maximum until the impact.

[0038] The fourth feature value F4 is the average value of the angular velocity ωy from the top to the impact, and can be calculated by dividing the cumulative value of the angular velocity ωy from the top to the impact by the time from the top to the impact.

[0039] In this embodiment, since a swing is performed multiple times, a swing feature amount for each swing, i.e., multiple swing feature amounts, are stored in storage unit 210. As described above, each swing feature amount includes first to fourth feature amounts F1 to F4, respectively.

[0040] [First Decision Section] The first determination unit 203 can execute a step of determining, for each swing, a plurality of shaft indices for identifying the specifications of the shaft 22 to be recommended to the golfer 3 based on each swing characteristic amount (step S4 in FIG. 3). The shaft indices are indices that are useful for specifically identifying the shaft 22. As already disclosed in Patent Document 1, if the swing characteristic amounts of a golfer are known through analysis of the results of numerous hitting tests, it is possible to determine a shaft indices suitable for that swing. Here, a shaft (or shaft indices) suitable for a certain swing refers to a shaft (or shaft indices) that, when swung with a golf club 2 having a pre-specified head 23, results in a longer ball flight distance and less lateral deviation. The specific head 23 may be, for example, a head 23 already used by the golfer 3 or a head that the golfer plans to use.

[0041] The first determination unit 203 of this embodiment first determines an ideal bending stiffness value (hereinafter sometimes referred to as "EI value") for each position of the shaft 22 based on the swing feature amount (first determination step), and then determines "IFC", which is one of the shaft indicators, based on the EI value (second determination step). The first determination step and the second determination step will be described in detail below. However, in other aspects, the first determination unit 203 may directly determine "IFC" based on the swing feature amount, or may use the EI value as the shaft indicator.

[0042] [First decision step] In this embodiment, one shaft index is made up of EI values ​​at four positions (described below) in the axial direction of the shaft 22. Therefore, one shaft index is a set of four EI values. Identifying the four EI values ​​helps to specifically identify the specifications of the shaft 22. Furthermore, multiple shaft indexes means that there are multiple shaft indexes that are sets of four EI values.

[0043] 6 shows the relational expressions between the first to fourth feature amounts F1 to F4 calculated by the calculation unit 202 and the corresponding appropriate EI values. These relational expressions are determined for each of a plurality of predetermined head speed bands (indicated by "HS" in FIG. 6, in units of m / s). In this embodiment, the head speed bands are divided into three or four. These relational expressions are stored in advance in the first storage unit 210A.

[0044] As disclosed in Patent Documents 1 and 2, through the analysis of the results of a large number of hitting tests, it is possible to roughly identify the relationship between the first to fourth feature amounts F1 to F4 of the golfer 3 and the distribution of EI values ​​at predetermined positions in the axial direction of the shaft 22 that are suitable for that swing. This point will be briefly explained below.

[0045] Fig. 7 is a plan view of the shaft 22. As shown in Fig. 7, when the shaft 22 is virtually divided into four regions a to d, the axial distribution of the EI values ​​of the shaft 22 can be identified as representative EI values ​​for each of the regions a to d. Specifically, the EI values ​​of the regions a to d are measured at positions P1 to P4, which are 36 inches, 26 inches, 16 inches, and 6 inches axially from the tip end 22a of the shaft 22, respectively. It has been found that the EI values ​​at these positions P1 to P4 are correlated with the first to fourth feature amounts F1 to F4, respectively.

[0046] Therefore, in this embodiment, by performing regression (simple regression) on the results of the impact test, assuming a specific head 23, relational expressions (approximate expressions) showing the relationship between each of the first to fourth feature amounts F1 to F4 and the EI values ​​at each axial position P1 to P4 of the shaft 22 appropriate for each head speed range are calculated in advance as shown in FIG. 6, and these are stored in the first storage unit 210A. Note that the axial positions P1 to P4 of the shaft 22, which are the measurement points, are not limited to the above-mentioned embodiment and may be changed within approximately ±2 inches from the above-mentioned positions. The EI value at each position is measured by the method described in Patent Document 1.

[0047] As is clear from FIG. 6, each of the relational expressions indicates that as the first to fourth feature amounts F1 to F4 increase, the EI value at each of the positions P1 to P4 on the shaft 22 increases proportionally (the shaft 22 becomes stiffer). Furthermore, each of the relational expressions indicates that as the head speed increases, the EI value at each of the positions P1 to P4 on the shaft 22 that is appropriate for that increase increases (the shaft 22 becomes stiffer). While each of the relational expressions in this embodiment employs a linear expression, the present invention is not limited to this. Furthermore, the divisions of the head speed bands in each of the relational expressions in FIG. 6 are merely examples, and the number of divisions and the specific ranges of head speed may be changed as appropriate.

[0048] As described above, the first determination unit 203 can determine an EI value suitable for each of a plurality of swings based on the first to fourth feature amounts F1 to F4, the average head speed of the golfer, and the above relational expressions. More specifically, in this embodiment, one shaft index is determined for each swing, and this one shaft index includes four EI values ​​at positions P1 to P4 in the axial direction.

[0049] [Second decision step] The first determination unit 203 of this embodiment determines "IFC" based on the EI value determined in the first determination step. IFC is an abbreviation for International Flex Cord, and is an index that more generally or universally represents the range of EI values ​​at each of positions P1 to P4 in the axial direction of the shaft 22.

[0050] The EI value at each position P1 to P4 on the shaft is converted into an IFC value (an integer from 0 to 9) using an EI value-IFC conversion table such as that shown in Fig. 8. The IFC is a four-digit number (e.g., "5655") obtained by arranging the four IFC values ​​of each of regions a to d of shaft 22 in order, and it is possible to identify a shaft 22 having a certain bending rigidity distribution.

[0051] As described above, the first determination unit 203 of this embodiment can determine, for each swing, multiple shaft indicators (IFCs in this embodiment) for specifying the specifications of the shaft 22 to be recommended to the golfer 3 based on the respective swing features.

[0052] FIG. 9 visualizes the data acquired from one swing through the above process. First and second measurement values ​​are acquired from the swing. From the first measurement values, swing feature amounts, EI values ​​at multiple positions on the shaft, and shaft indexes are calculated sequentially. The second measurement values ​​include the flight distance and lateral deviation of the ball. In this embodiment, these data are acquired or calculated for each of multiple swings.

[0053] [Type number discrimination section] The number-of-types determining unit 204 executes a step of determining the number of types of the plurality of shaft indicators (IFC) determined by the first determining unit 203 (step S5 in FIG. 3). The number-of-types determining unit 204 compares the plurality of shaft indicators (IFC) and determines their number of types (number of patterns). If all the shaft indicators are the same four-digit number, the number-of-types determining unit 204 outputs 1 as the number of types, and in other cases outputs a number according to the number of types of the shaft indicators. The output value of the number-of-types determining unit 204 is stored in the memory unit 210.

[0054] [Selection mode switch] When the second measurement values ​​(i.e., the trajectories of the golf ball 4 obtained from multiple swings) are analyzed, it may be estimated that a mis-shot is included. Here, a mis-shot refers to a swing and / or the trajectory of the golf ball 4 in which the flight distance and / or lateral deviation of the golf ball 4 is greater than a predetermined reference value compared to other trajectories. In such cases, it may be effective to recommend to the golfer a shaft 22 that is specialized to correct the mis-shot in order to help the golfer improve his or her score.

[0055] On the other hand, when analyzing the second measurement value, it may be possible to estimate that there is a certain degree of variation in the swing, even if it is not a mishit. In such cases, it may be effective to recommend to the golfer multiple shafts 22 that are each suited to each swing.

[0056] For the above reasons, it is important to appropriately switch the selection mode for the shaft 22 to be recommended based on the second measurement value and recommend a shaft 22 that better matches the golfer's swing. In consideration of this situation, the fitting system 1 and fitting method of this embodiment introduce a selection mode switching unit 205. Specifically, the selection mode switching unit 205 of this embodiment determines whether there are multiple types of recommended shaft indicators (step S6 in FIG. 3), and if the result is affirmative (Y in step S6), executes selection mode switching processing (step S8).

[0057] The selection mode switching process, the details of which will be described later, switches the selection mode for selecting a shaft 22 between a first selection mode (steps S84, S89) and a second selection mode (steps S85, S90) based on the second measurement value, as shown in FIG. 10. The first and second selection modes employ different shaft recommendation criteria. This allows a shaft 22 selected using a different selection mode to be recommended to the golfer. If the result of the determination in step S6 is negative (N in step S6 in FIG. 3), since only one shaft indicator has been determined, this shaft indicator is ultimately determined to be the first shaft indicator, which is an indicator for identifying the shaft 22 to be recommended to the golfer (step S7).

[0058] In a preferred embodiment, the selection mode switching process may calculate the difference between the maximum and minimum values ​​from a plurality of second measurement values, and switch the selection mode based on this difference. The second measurement values ​​include first trajectory information related to the flight distance of the golf ball 4 and / or second trajectory information related to the lateral deviation from the target flight line. Therefore, the difference may be the difference between the maximum and minimum values ​​for the flight distance and / or the difference between the maximum and minimum values ​​for the lateral deviation. In this embodiment, the first selection mode is selected when the difference is equal to or greater than a predetermined reference value, and the second selection mode is selected when the difference is smaller than the reference value.

[0059] Next, with reference to FIG. 10, an example of a more detailed processing procedure of the selection mode switching processing of this embodiment will be shown.

[0060] 10, the selection mode switching unit 205 determines whether the number of shaft indicator types determined in step S4 is three or more (step S81). If the result of step S31 is negative (N in step S81), the selection mode switching unit 205 refers to the second measurement values ​​of the multiple swings and extracts the best shot and the worst shot (step S82). This extraction step is executed by the superiority / inferiority determining unit 206 of the selection mode switching unit 205, as shown in FIG.

[0061] [Superiority Discrimination Department] The superiority / inferiority determining unit 206 determines the superiority / inferiority of a swing, the best shot, the worst shot, etc., based on, for example, the first trajectory information (i.e., information related to the flight distance of the hit golf ball 4). More specifically, the superiority / inferiority determining unit 206 can sort the swings by the flight distance of the hit ball, and set a flag indicating that the longer the flight distance, the better the shot. Furthermore, the superiority / inferiority determining unit 206 can determine the swing that has achieved the greatest flight distance as the best shot (best swing), and the swing that has achieved the shortest flight distance as the worst shot (worst swing).

[0062] In another aspect, the superiority / inferiority determining unit 206 can determine the best shot and the worst shot, for example, based on the second trajectory information (i.e., information regarding the left / right deviation of the hit ball from the target flight line). More specifically, the superiority / inferiority determining unit 206 can sort the swings by the magnitude of the left / right deviation of the hit ball, and set a flag indicating that the shot with the smaller deviation is better. Furthermore, the superiority / inferiority determining unit 206 can determine the swing with the smallest deviation as the best shot (best swing), and the swing with the largest left / right deviation as the worst shot (worst swing).

[0063] In yet another aspect, the superiority / inferiority determining unit 206 may determine the superiority / inferiority of a swing according to criteria that use both the first trajectory information and the second trajectory information. In this case, for example, a composite evaluation value may be calculated by multiplying the first trajectory information and / or the second trajectory information by a coefficient or the like, and the swings may be sorted based on this evaluation value to determine the best shots and the worst shots.

[0064] Next, the selection mode switching unit 205 of this embodiment calculates the difference in flight distance and the difference in left-right deviation between the best shot and the worst shot. The selection mode switching unit 205 determines whether the difference in flight distance is 5 yards or more and the difference in left-right deviation is 10 yards or more (step S83). In this embodiment, if the result of step S83 is affirmative (Y in step S83), the selection mode is switched to the first selection mode (step S84). On the other hand, if the result of step S83 is negative (N in step S83), the selection mode is switched to the second selection mode (step S85). Note that the conditions and reference values ​​that serve as the criteria for judgment in step S83 can be changed as appropriate, for example, depending on the skill of the golfer being fitted.

[0065] [First selection mode] 11 shows an example of the details of the first selection mode of this embodiment, which is executed by the second determination unit 207. The first selection mode of this embodiment is executed when the difference between the best shot and the worst shot is equal to or greater than a predetermined reference value. In this case, the worst shot is likely to be a mishit. Therefore, the first selection mode of this embodiment functions to select a shaft 22 that is specialized for correcting mishits for the golfer, with the aim of improving the golfer's score.

[0066] More specifically, in the first selection mode, weights are first set to a plurality of swings based on the merits of the swings (step S101). This step is executed by the weighting unit 208 of the second determination unit 207, as shown in FIG. 2. A "weight" is a coefficient set according to the viewpoint of fitting, and the larger the weight, the more the swing influences the fitting result. The weighting unit 208 of this embodiment sets the weight w2 of the swing of the worst shot to be larger than the weight w1 of the swing of the best shot (w2>w1). Therefore, the weighting unit 208 of this embodiment can make the swing of the worst shot stand out more than the swing of the best shot.

[0067] The specific values ​​of the weights w1 and w2 (hereinafter, these may be collectively referred to as "weights wi") set for each swing are adjusted as appropriate and are not particularly limited. In this embodiment, the largest weight w2 is set to 2.0, and the smallest weight w1 is set to 0.5.

[0068] Next, a first shaft index that specifies the specifications of the shaft 22 to be recommended to the golfer is determined based on the plurality of swing feature amounts and the weight wi (step S102). This step S102 is executed by the second determination unit 207.

[0069] The second determination unit 207 of this embodiment determines a first shaft index to be recommended to the golfer by taking a weighted average of the multiple shaft indexes (these values ​​correspond to swing feature amounts) determined in step S4, taking into consideration the weight wi described above. Therefore, the first shaft index of this embodiment also consists of a set of EI values ​​at four positions P1 to P4 in the axial direction of the shaft 22.

[0070] Specifically, the EI value (EI (P1) ) can be determined by a weighted average as follows: EI (P1) =(w1 EI1 (P1) +w2 EI2 (P1) ) / (w1+w2) Here, w1 and w2 are weights set for the best shot swing and the worst shot swing, respectively, and EI1 (P1) and EI2 (P1) are the EI values ​​determined from the first feature amount F1 for the best shot swing and the worst shot swing, respectively.

[0071] Similarly, the EI value (EI (P2) ) can also be determined by a weighted average such as EI (P2) =(w1 EI1 (P2) +w2 EI2 (P2) ) / (w1+w2) Here, EI1 (P2) and EI2 (P2) are the EI values ​​determined from the second feature amount F2 for the best shot swing and the worst shot swing, respectively.

[0072] In addition, the EI values ​​at the first shaft index positions P3 and P4 (EI (P3) ) and (EI (P4) ) can also be determined by weighted averaging in the same way as above. This gives four EI values, EI(P1), EI (P2) , E.I. (P3)and EI (P4) A first shaft index consisting of a set of

[0073] In the first selection mode of this embodiment, the swing weight w2 of the worst shot is set to be greater than the swing weight w1 of the best shot. Therefore, the first shaft indicator determined in the first selection mode is an IFC for identifying one shaft 22 that is more suitable for the worst shot. The shaft 22 selected through this process is useful for providing a shot with a longer flight distance and less deviation to the left or right, even when making a swing that has previously resulted in the worst shot.

[0074] [Variation of the first selection mode] In the above example of the first selection mode, the shaft index is multiplied by a weight, but in other examples, the first swing feature amount may be determined by taking a weighted average of a plurality of swing feature amounts in consideration of the weights. Specifically, the first feature amount F1 of the first swing feature amount a can be determined by a weighted average such as: F1 a =(w1 F11 + w2 F12) / (w1 + w2) Here, w1 and w2 are the weights of the swings of the best shot and the worst shot, respectively, and F11 and F12 are the first feature amounts of the swings of the best shot and the worst shot, respectively.

[0075] Similarly, the second feature amount F2a of the first swing feature amount can be determined by the following weighted average. F2 a =(w1·F21+w2·F22) / (w1+w2) Here, F21 and F22 are the second feature amounts of the swings of the best shot and the worst shot, respectively.

[0076] In addition, the third feature F3 of the first swing feature a and the fourth feature F4 aSimilarly, the first to fourth feature values ​​F1 can be determined by the weighted average. a , F2 a , F3 a and F4 a Then, a first swing feature amount consisting of a set of:

[0077] Next, the second determination unit 207 determines a first shaft index based on the first swing feature amount. That is, a weighted average of multiple swing feature amounts is first calculated to calculate one first swing feature amount, and the first shaft index is determined based on this first swing feature amount. The fitting system 1, fitting device 200, and fitting method of this embodiment can also suggest a shaft suitable for a swing for which a large weight is set.

[0078] [Second selection mode] 12 shows an example of the details of the second selection mode of this embodiment, which is executed by the second determination unit 207. The second selection mode of this embodiment is executed when the difference between the best shot and the worst shot is smaller than a predetermined reference value. In this case, even if it cannot be said to be a miss shot, it is highly likely that there is a certain degree of variability in the golfer's swing. Therefore, the second selection mode of this embodiment functions to select multiple shafts 22 suitable for each individual swing of the golfer, from the viewpoint of providing the golfer with various options.

[0079] As shown in Fig. 12, in the second selection mode of this embodiment, for example, shaft indices that appear more frequently are ranked higher, and shaft indices that appear less frequently are ranked lower (step S201). In this specification, "ranking" refers to the degree of recommendation to the golfer who is the subject of fitting, with the higher the ranking, the higher the recommendation. This step is executed by the ranking unit 209 of the second determination unit 207, as shown in Fig. 2.

[0080] Here, the ranking will be explained using a specific example. Now, assume that the shaft indexes IFC determined in five swings are as follows: IFC:5655 selected as Swing 1 IFC:6655 selected for Swing 2 IFC:5655 decided on Swing 3 IFC:5655 decided on Swing 4 IFC:6655 selected as Swing 5 In the above case, the ranking unit 209 counts the number of occurrences of "5655" (3) and the number of occurrences of "6655" (2), and sorts the shafts by their number of occurrences. Then, the ranking unit 209 ranks the IFC "5655" with the most occurrences as the first shaft index, and then ranks the IFC "6655" as the second shaft index. This information is stored in the storage unit 210. In the second selection mode, the first shaft index is the IFC of the ranked shafts 22.

[0081] The selection mode switching unit 205 executes step S84 or step S85, whereby the first shaft index is determined, and then the first shaft index is displayed on the display unit 300 (step S9 in FIG. 3).

[0082] [Display] The display unit 300 is, for example, a display. The control unit 212 executes a step of displaying on the display unit 300 a first shaft index (for example, IFC) determined in the first selection mode or the second selection mode.

[0083] 13 shows an example of a fitting result in the first selection mode displayed on the display unit 300. As shown in FIG. 13, the display unit 300 of this embodiment visually displays the IFC of the recommended shaft 22. The display unit 300 of this embodiment shows, as an example, "5655" as an IFC specialized for correcting mishits as a recommended shaft. In another aspect, instead of the IFC, the display unit 300 may display EI values ​​at four positions P1 to P4 in the shaft axial direction as information corresponding to the first shaft index.

[0084] Furthermore, in this embodiment, the control unit 212 can display the "cocking movement" during a swing on the display unit 300. This "cocking movement" corresponds to the magnitudes of the first to fourth feature amounts F1 to F4 in the swing feature amount.

[0085] Furthermore, in this embodiment, the control unit 212 can display a list (compatible shaft list) of one or more shafts that satisfy the recommended IFC on the display unit 300. Displaying such a compatible shaft list can be easily achieved by previously storing a database in the first storage unit 210A that associates the IFC with the product numbers, etc., of the compatible shafts.

[0086] Fig. 14 shows an example of fitting results in the second selection mode displayed on the display unit 300. As shown in Fig. 14, the display unit 300 of this embodiment visually displays the ranked IFCs of the recommended shafts 22. For example, the upper part of the display unit 300 displays IFC "5655" as the first recommended shaft, and the lower part displays IFC "6655" as the second recommended shaft.

[0087] In the above example, the recommended shaft (No. 1) is a shaft that is suitable for swings 1, 3, and 4. That is, the recommended shaft (No. 1) tends to produce a longer ball flight distance and a smaller left-right deviation when swings 1, 3, and 4 are performed. On the other hand, the recommended shaft (No. 2) is a shaft that is suitable for swings 2 and 5 above. That is, the recommended shaft (No. 2) tends to produce a longer ball flight distance and a smaller left-right deviation when swings 2 and 5 are performed.

[0088] In this way, by ranking and displaying the shaft indices by the number of times they appear, it is possible to suggest not only the best shaft indices that are more in line with the golfer's swing tendencies, but also the so-called second best. In the example of Fig. 14, the shaft indices are displayed up to the second best, but depending on the fitting results, shaft indices from the third best onwards may be displayed.

[0089] As described above, according to the fitting system 1, fitting device 200, and fitting method of this embodiment, by adopting the above configuration, it is possible to propose golf club shafts that can meet the diverse needs of golfers.

[0090] In step S81 of FIG. 10, if the number of types of shaft indicators is three or more (Y in step S81), the ranking unit 209 ranks the shaft indicators by the number of applications, and extracts the swing and trajectory corresponding to the first-ranked shaft indicator as the best shot, and the swing and trajectory corresponding to the second-ranked or lower shaft indicator as the worst shot (step S86).

[0091] Next, the selection mode switching unit 205 of this embodiment calculates the difference in flight distance and the difference in left-right deviation between the best shot and the second-worst shot. Then, it determines whether the difference in flight distance is 5 yards or more and the difference in left-right deviation is 10 yards or more (step S87), and if the result is positive (Y in step S83), the first selection mode is executed (step S89). As described above, if the result of step S87 is positive, it can be estimated that a mis-shot is included in the swing.

[0092] Similarly, the selection mode switching unit 205 calculates the difference in flight distance and the difference in left-right deviation between the best shot and the third worst shot, and determines whether the difference in flight distance is 5 yards or more and the difference in left-right deviation is 10 yards or more (step S88).If the result is positive (Y in step S88), the first selection mode is executed (step S89).

[0093] On the other hand, if the results of steps S87 and S87 are both negative (N), it can be inferred that there is a variation in the swings rather than that there are miss shots among the multiple swings. Therefore, in these cases, the second selection mode is executed (step S90).

[0094] In the above embodiment, an index related to the bending stiffness value of the shaft 22 is used as the shaft index to select a shaft 22 suitable for the golfer 3. However, the present disclosure allows various indexes already known at the time of filing of this application to be used as the shaft index instead of or in addition to the index related to bending stiffness. Such indexes may be, for example, the weight or moment of inertia of the shaft 22 (and / or the golf club 2). Fitting of these shaft indexes may be performed according to known methods, such as those described in Patent Document 2 (the entire contents of Patent Documents 1 and 2 are incorporated herein by reference).

[0095] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above specific disclosure, and can be implemented with various modifications within the scope of the technical idea described in the claims.

[0096] [Note] The present disclosure includes the following aspects.

[0097] [Disclosure 1] A fitting device for selecting a golf club shaft suitable for a golfer, an acquisition unit that acquires first measurement values ​​from a swing sensor that is acquired by making a swing to hit a golf ball multiple times using a golf club to which a swing sensor is attached in an environment where a trajectory measurement device is installed, and second measurement values ​​related to the trajectory of the golf ball that are measured by the trajectory measurement device; a calculation unit that calculates a swing feature amount for each of the plurality of swings based on the first measurement value; a first determination unit that determines, for each of the swings, a plurality of shaft indices for specifying specifications of a shaft to be recommended to the golfer based on the respective swing feature amounts; a type number determining unit that determines the number of types of the determined shaft indicators; a selection mode switching unit that switches a selection mode for selecting the shaft between a first selection mode and a second selection mode different from the first selection mode based on the second measurement value when there are multiple types of shaft indicators; a second determination unit that determines a first shaft index for specifying specifications of a shaft to be recommended to the golfer from the plurality of shaft indexes according to the switched selection mode, Golf club shaft fitting device. [Disclosure 2] A golf club shaft fitting device as described in the present disclosure 1, wherein the selection mode switching unit switches to the first selection mode when the difference between the maximum and minimum values ​​of the second measurement value is greater than or equal to a predetermined reference value, and switches to the second selection mode when the difference is smaller than the reference value. [Disclosure 3] a superiority / inferiority determining unit that determines the superiority / inferiority of the plurality of swings based on the second measurement value; a weighting unit that sets weights for the plurality of swings based on the superiority or inferiority of the swings, 3. The golf club shaft fitting device according to Disclosure 1 or 2, wherein the first selection mode determines the first shaft index based on the swing feature amount and the weight. [Disclosure 4] A golf club shaft fitting device as described in Disclosure 3, wherein in the first selection mode, the second determination unit determines the first shaft index by taking a weighted average of the multiple shaft indexes or indexes corresponding thereto, taking the weights into consideration. [Disclosure 5] In the first selection mode, the first determination unit determines a first swing feature amount by taking a weighted average of the plurality of swing feature amounts in consideration of the weights, The golf club shaft fitting device according to Present Disclosure 3, wherein the second determination unit determines the first shaft index based on the first swing feature amount. [Disclosure 6] the second measurement value includes first trajectory information relating to the distance traveled by the golf ball; 6. The golf club shaft fitting device according to any one of Disclosures 3 to 5, wherein the quality determining unit determines the quality of the swing based on the first trajectory information. [Disclosure 7] the second measurement value includes second trajectory information relating to a lateral deviation of the golf ball from a predetermined target flight line; The golf club shaft fitting device according to any one of Disclosures 3 to 5, wherein the superiority / inferiority determining unit determines the superiority / inferiority of the swing based on the second trajectory information. [Disclosure 8] the quality determination unit determines a best shot having the best second measurement value and a worst shot having the worst second measurement value, 8. The golf club shaft fitting device according to any one of Disclosures 4 to 7, wherein the weighting unit sets the weight of the swing of the worst shot to be greater than the weight of the swing of the best shot. [Disclosure 9] further comprising a ranking unit that ranks the plurality of shaft indicators by the number of occurrences thereof; The golf club shaft fitting device according to any one of Disclosures 1 to 8, wherein the second selection mode determines the first shaft index according to the ranking. [Disclosure 10] 10. A golf club shaft fitting device according to any one of Disclosures 1 to 9, wherein the first shaft indicator includes an indicator relating to the bending stiffness of the shaft. [Disclosure 11] 11. A golf club shaft fitting device according to any one of Disclosures 1 to 10, wherein the first shaft indicator includes an indicator relating to the weight of the shaft. [Disclosure 12] A golf club shaft fitting system including the fitting device described in any one of claims 1 to 11, the swing sensor for measuring the first measurement value; the trajectory measurement device for measuring the second measurement; and a display unit that displays the first shaft indicator or an indicator corresponding thereto. Golf club shaft fitting system. [Disclosure 13] A fitting method for selecting a golf club shaft suitable for a golfer, comprising: A step of using a golf club equipped with a swing sensor to make a swing that hits a golf ball multiple times in an environment where a trajectory measurement device is installed, and acquiring a first measurement value from the swing sensor and a second measurement value related to the trajectory of the golf ball measured by the trajectory measurement device; calculating a swing feature amount for each of the plurality of swings based on the first measurement value; determining, for each swing, a plurality of shaft indices for specifying shaft specifications to be recommended to the golfer based on the respective swing feature amounts; determining the number of types of the determined shaft indicators; When there are a plurality of types of shaft indicators, switching a selection mode for selecting the shaft to either a first selection mode or a second selection mode different from the first selection mode based on the second measurement value; and determining a first shaft index for specifying specifications of a shaft to be recommended to the golfer from the plurality of shaft indexes in accordance with the switched selection mode. How to fit a golf club shaft. [Disclosure 14] 14. A golf club shaft fitting method according to Disclosure 13, further comprising the step of displaying the first shaft indicator or an indicator corresponding thereto. [Disclosure 15] A fitting program for selecting a golf club shaft suitable for a golfer, comprising: A step of using a golf club equipped with a swing sensor to make a swing that hits a golf ball multiple times in an environment where a trajectory measurement device is installed, and acquiring a first measurement value from the swing sensor and a second measurement value related to the trajectory of the golf ball measured by the trajectory measurement device; calculating a swing feature amount for each of the plurality of swings based on the first measurement value; determining, for each swing, a plurality of shaft indices for specifying shaft specifications to be recommended to the golfer based on the respective swing feature amounts; determining the number of types of the determined shaft indicators; When there are a plurality of types of shaft indicators, switching a selection mode for selecting the shaft to either a first selection mode or a second selection mode different from the first selection mode based on the second measurement value; determining a first shaft index for specifying specifications of a shaft to be recommended to the golfer from the plurality of shaft indexes in accordance with the switched selection mode; Golf club shaft fitting program. [Disclosure 16] 16. The golf club shaft fitting program of Disclosure 15, further comprising the step of displaying the first shaft indicator or an indicator corresponding thereto. [Explanation of symbols]

[0098] 1. Fitting System 2. Golf clubs 3. Golfer 4 golf balls 5 Swing 22 shaft 100 Swing Sensor 200 Fitting Device 201 Acquisition Department 202 Calculation Unit 203 First Decision Section 204 Type and Number Discrimination Unit 205 Selection mode switching section 206 Superiority and Inferiority Judgment Department 207 Second Decision Section 208 Weighting section 209 Ranking Section F1~F4 First to fourth feature

Claims

1. A fitting device for selecting a golf club shaft suitable for a golfer, an acquisition unit that acquires first measurement values ​​from a swing sensor and second measurement values ​​related to the trajectory of the golf ball measured by the trajectory measurement device, the first measurement values ​​being acquired by making multiple swings to hit a golf ball using a golf club to which a swing sensor is attached in an environment where a trajectory measurement device is installed; a calculation unit that calculates a swing feature amount for each of the plurality of swings based on the first measurement value; a first determination unit that determines, for each swing, a plurality of shaft indices for specifying specifications of a shaft to be recommended to the golfer based on each of the swing feature amounts; a type number determining unit that determines the number of types of the determined shaft indicators; a selection mode switching unit that switches a selection mode for selecting the shaft between a first selection mode and a second selection mode different from the first selection mode based on the second measurement value when there are multiple types of shaft indicators; a second determination unit that determines a first shaft index for specifying specifications of a shaft to be recommended to the golfer from the plurality of shaft indexes in accordance with the switched selection mode, the selection mode switching unit switches to the first selection mode when a difference between a maximum value and a minimum value of the second measurement value is equal to or greater than a predetermined reference value, and switches to the second selection mode when the difference is smaller than the reference value. Golf club shaft fitting device.

2. A superiority / inferiority discrimination unit that discriminates the superiority / inferiority of the plurality of swings based on the second measurement value; a weighting unit that sets weights for the plurality of swings based on the superiority or inferiority of the swings, The golf club shaft fitting device according to claim 1 , wherein the first selection mode determines the first shaft index based on the swing feature amount and the weight.

3. A golf club shaft fitting device as described in Claim 2, wherein in the first selection mode, the second determination unit determines the first shaft index by taking a weighted average of multiple shaft indexes or corresponding indexes taking into account the weights.

4. In the first selection mode, the first determination unit determines a first swing feature amount by taking a weighted average of the plurality of swing feature amounts in consideration of the weights, The golf club shaft fitting device according to claim 2 , wherein the second determination unit determines the first shaft index based on the first swing feature amount.

5. The second measurement value includes first trajectory information regarding the flight distance of the golf ball, The golf club shaft fitting device according to claim 2 , wherein the quality determining unit determines whether the swing is good or bad based on the first trajectory information.

6. the second measurement value includes second trajectory information relating to a lateral deviation of the golf ball from a predetermined target flight line; The golf club shaft fitting device according to claim 2 , wherein the quality determining unit determines whether the swing is good or bad based on the second trajectory information.

7. The superiority / inferiority determination unit determines a best shot having the best second measurement value and a worst shot having the worst second measurement value, 7. The golf club shaft fitting device according to claim 3, wherein the weighting section sets a weight for the swing of the worst shot greater than a weight for the swing of the best shot.

8. The method further includes a ranking unit that ranks the plurality of shaft indicators by the number of occurrences thereof, The golf club shaft fitting device according to claim 1 , wherein the second selection mode determines the first shaft index according to the ranking.

9. A golf club shaft fitting device as described in any one of claims 1 to 8, wherein the first shaft indicator includes an indicator relating to the bending stiffness of the shaft.

10. The golf club shaft fitting device according to claim 1 , wherein the first shaft index includes an index relating to the weight of the shaft.

11. A golf club shaft fitting system including the fitting device described in any one of claims 1 to 10, the swing sensor for measuring the first measurement value; the trajectory measurement device for measuring the second measurement; a display unit that displays the first shaft indicator or an indicator corresponding thereto, Golf club shaft fitting system.

12. A fitting method for selecting a golf club shaft suitable for a golfer, comprising: In an environment where a trajectory measurement device is installed, a golf club having a swing sensor attached thereto is used to make a plurality of swings to strike a golf ball, and a first measurement value is obtained from the swing sensor, and a second measurement value relating to the trajectory of the golf ball is measured by the trajectory measurement device; calculating a swing feature amount for each of the plurality of swings based on the first measurement value; determining, for each swing, a plurality of shaft indices for specifying shaft specifications to be recommended to the golfer based on the respective swing feature amounts; determining the number of types of the determined shaft indicators; a step of switching a selection mode for selecting the shaft to either a first selection mode or a second selection mode different from the first selection mode based on the second measurement value when there are multiple types of shaft indicators, wherein the step of switching to the first selection mode is performed when a difference between a maximum value and a minimum value of the second measurement value is equal to or greater than a predetermined reference value, and the step of switching to the second selection mode is performed when the difference is smaller than the reference value; and determining a first shaft index for specifying specifications of a shaft to be recommended to the golfer from the plurality of shaft indexes in accordance with the switched selection mode. How to fit a golf club shaft.

13. A golf club shaft fitting method as described in claim 12, further comprising the step of displaying the first shaft indicator or an indicator corresponding thereto.

14. A fitting program for selecting a golf club shaft suitable for a golfer, comprising: In an environment where a trajectory measurement device is installed, a golf club having a swing sensor attached thereto is used to make a plurality of swings to strike a golf ball, and a first measurement value is obtained from the swing sensor, and a second measurement value relating to the trajectory of the golf ball is measured by the trajectory measurement device; calculating a swing feature amount for each of the plurality of swings based on the first measurement value; determining, for each swing, a plurality of shaft indices for specifying shaft specifications to be recommended to the golfer based on the respective swing feature amounts; determining the number of types of the determined shaft indicators; a step of switching a selection mode for selecting the shaft to either a first selection mode or a second selection mode different from the first selection mode based on the second measurement value when there are multiple types of shaft indicators, wherein the step of switching to the first selection mode is performed when a difference between a maximum value and a minimum value of the second measurement value is equal to or greater than a predetermined reference value, and the step of switching to the second selection mode is performed when the difference is smaller than the reference value; determining a first shaft index for specifying specifications of a shaft to be recommended to the golfer from the plurality of shaft indexes in accordance with the switched selection mode; Golf club shaft fitting program.

15. A golf club shaft fitting program as described in claim 14, further comprising a step of displaying the first shaft indicator or an indicator corresponding thereto.

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