Abstract: A method for extracting impact time in a golf swing includes acquiring at least one chronological waveform among chronological waveforms of an angular velocity about x-axis, an angular velocity about y-axis, and an angular velocity about z-axis obtained when a golf ball is hit by a golf club attached with a sensor that measures angular velocities about three axes, when the x-axis is orientated along a toe-heel direction of a golf club head, when the y-axis is orientated so as to follow along a direction in which a ball is hit, and when the z-axis is orientated to match an axial direction of a shaft; acquiring timing at which laser light, disposed immediately in front of where the golf club head impacts the ball, is shielded by the golf club head or the shaft; and determining an impact time using the at least one chronological waveform and the timing.

Abstract: An evaluation method for hit feeling of a sport implement according to the present invention includes an acceleration measurement step for measuring acceleration of a sport hitting tool 4 and a data analysis step for analyzing data obtained in the measurement. In the data analysis step, an amount of change in acceleration in a first cycle of vibration after hitting is calculated. The evaluation method evaluates hit feeling to be felt by a person, using the amount of change in the acceleration. Preferably, in the data analysis step, an amount of change in acceleration in the first cycle of predetermined time is calculated. The predetermined time is within 1.5 msec from the time of hitting. Preferably, the sport hitting tool 4 has the hitting section detachably attached to a shaft section.

Abstract: A golf club 2 includes a head 4, a shaft 6, and a grip 8. A club inertia moment about a swing axis is defined as Isw. A club inertia moment about a grip end is defined as Ige. Ige is 2760(kg·cm2) or greater and less than 2820(kg·cm2). Isw/Ige is equal to or less than 2.42. A club weight is defined as Wc (kg), an axial direction distance from the grip end to a center of gravity of the club is defined as Lc (cm), and a club inertia moment about the center of gravity of the club is defined as Ic(kg·cm2). Isw is calculated by Equation (1) below. Ige is calculated by Equation (2) below.

Abstract: A golf club 2 includes a head 4, a shaft 6, and a grip 8. A club inertia moment about a swing axis is defined as Isw. A club inertia moment about a grip end is defined as Ige. Ige is 2820 (kg·cm2) or greater and less than 2870 (kg·cm2). Isw/Ige is equal to or less than 2.42. A club weight is defined as Wc (kg), an axial direction distance from the grip end to a center of gravity of the club is defined as Lc (cm), and a club inertia moment about the center of gravity of the club is defined as Ic (kg·cm2). Isw is calculated by Equation (1) below. Ige is calculated by Equation (2) below.

Abstract: A golf club 2 includes a head 4, a shaft 6, and a grip 8. A club inertia moment about a swing axis is defined as Isw. A club inertia moment about a grip end is defined as Ige. Ige is 2870 (kg·cm2) or greater and less than 2920 (kg·cm2). Isw/Ige is equal to or less than 2.46. A club weight is defined as Wc (kg), an axial direction distance from the grip end to a center of gravity of the club is defined as Lc (cm), and a club inertia moment about the center of gravity of the club is defined as Ic (kg·cm2). Isw is calculated by Equation (1) below. Ige is calculated by Equation (2) below.

Abstract: A golf club 2 includes a head 4, a shaft 6, and a grip 8. A club inertia moment about a swing axis is defined as Isw. A club inertia moment about a grip end is defined as Ige. Ige is 2920 (kg·cm2) or greater and less than 2970 (kg·cm2). Isw/Ige is equal to or less than 2.48. A club weight is defined as Wc (kg), an axial direction distance from the grip end to a center of gravity of the club is defined as Lc (cm), and a club inertia moment about the center of gravity of the club is defined as Ic (kg·cm2). Isw is calculated by Equation (1) below. Ige is calculated by Equation (2) below.

Abstract: Provided is a fitting apparatus that accurately and objectively determines an optimal swingability index, which is a swingability index of a golf club suited to a golfer. The fitting apparatus is provided with an acquisition unit, a calculation unit, and a determination unit. The acquisition unit acquires a measurement value obtained by measuring a swing action of a test club by the golfer with a measurement device. The calculation unit calculates a swing index indicating a feature amount of the swing action, based on the measurement value. The determination unit determines the optimal swingability index, according to a magnitude of the swing index.

Abstract: A golf swing analysis apparatus for analyzing a swing action of a golf club is provided. The golf swing analysis apparatus comprises an acquisition unit configured to acquire a measurement value obtained by measuring the swing action using a measurement device; a grip behavior derivation unit configured to derive a behavior of a grip of the golf club that occurs during the swing action, based on the measurement value; and a shoulder behavior derivation unit configured to derive a behavior of a pseudo shoulder of a golfer that occurs during the swing action, based on the behavior of the grip.

Abstract: The evaluation method includes a first step, by using measurement means M1 which can measure force F acting between a swing subject and the sport hitting tool or a specific directional component F1 thereof, obtaining measured value Vf of the force F or the force F1 at time after the impact, and a second step of determining the hit feeling on the basis of the measured value Vf at least at the one time. Preferably, the force F or the force F1 is force Fs containing a component in a shear direction. Preferably, in the first step, the measured values Vf in a specific interval Z 12 from time T1 to T2 after the impact are obtained chronologically. Preferably, the evaluation is made based on a difference between a maximum value and a minimum value of the measured values Vf.

Abstract: A golf club having a head disposed at a front end of a shaft and having a grip disposed at a back end of the shaft. The golf club includes a sensor section arranged on a grip-end edge of the grip and used for analyzing action of a golf swing.

Abstract: A camera 10 photographs a golf player swinging a golf club to hit a golf ball and the golf club. Image data is obtained by photographing. A calculating part 16 extracts a plurality of frames from the image data. The calculating part 16 determines a check frame in which the golf player is in a predetermined posture from the plurality of frames. The calculating part 16 determines a contour of the golf player from the check frame. The calculating part 16 decides a swing from the contour of the golf player. An extreme value constituting the contour is determined in deciding the swing. A feature point is determined from the extreme value. The swing is diagnosed using the feature point.

Abstract: A method and system for correcting a silhouette of a person extracted from an image by labeling each pixel as the person or the background are disclosed. The pixels in a target region are corrected by: a step in which, by the use of pixels in the target region labeled as the person, a person histogram is created; a step in which, by the use of pixels in the target region labeled as the background, a background histogram is created; a step in which, for each pixel in the target region, by the use of the person histogram, the background histogram and color data of each pixel in the target region, first connective costs of the pixel to the color data of the person and the background are calculated; and a step in which, for each pixel in the target region, a second connective cost of the pixel is calculated.

Abstract: A method for extracting impact time in a golf swing includes acquiring at least one chronological waveform among chronological waveforms of an angular velocity about x-axis, an angular velocity about y-axis, and an angular velocity about z-axis obtained when a golf ball is hit by a golf club attached with a sensor that measures angular velocities about three axes, when the x-axis is orientated along a toe-heel direction of a golf club head, when the y-axis is orientated so as to follow along a direction in which a ball is hit, and when the z-axis is orientated to match an axial direction of a shaft; acquiring timing at which laser light, disposed immediately in front of where the golf club head impacts the ball, is shielded by the golf club head or the shaft; and determining an impact time using the at least one chronological waveform and the timing.

Abstract: A method for measuring behavior of a head of a golf club and of a ball includes obtaining two-dimensional data of three or more marks on a face surface at two points in time before impact; identifying three-dimensional positions of the marks on the two points in time from the two-dimensional data; identifying behavior of the face surface of the three-dimensional position of each mark at the two points in time; identifying time of a contact of the face surface with the ball; estimating behavior of the head at the time of contact of the face surface with the ball; obtaining two-dimensional data of the ball at the two points in time; identifying three-dimensional position and posture of the ball at the two points in time; and estimating a behavior value of the ball from the three-dimensional position and posture of the ball.

Abstract: An analysis method includes the steps of: measuring a swing of a golf club to which a sensor capable of measuring accelerations in directions of three axes and angular velocities or angles about the three axes is attached; obtaining an index for classifying the swing based on a measuring result of the sensor; and classifying the swing based on the index. The index includes the item (a) or (b): (a) a grip angular velocity at least at one time during a downswing; and (b) a grip velocity at least at one time during the downswing. Preferably, times of an address, a top, and an impact are determined in the analysis method.

Abstract: A golf club having a head disposed at a front end of a shaft and having a grip disposed at a back end of the shaft. The golf club includes a sensor section arranged on a grip-end edge of the grip and used for analyzing action of a golf swing.

Abstract: A valuation method of the present invention quantitatively estimates hit feeling of a sport hitting tool. The evaluation method includes: a first step of using a measuring means M1 capable of measuring forces F acting between a swing subject and the sport hitting tool or specific directional components F1 thereof to obtain values of the forces F or the components F1 at times after impact; and a second step of deciding the hit feeling based on the value of the force F or the component F1 at at least one of the times. Preferably, the values of the forces F or the components F1 in a specified period Z12 between a time T1 and a time T2 after the impact are obtained in time series in the first step. Preferably, the hit feeling is evaluated based on an integrated value Sf of the forces F or the components F1 in the specified period Z12 in the second step.

Abstract: A fitting method of a shaft of a golf club for selecting a shaft matching a golfer based on a swing of the golfer. The method includes the steps of obtaining measurement values from a sensor attached to a grip of a golf club; determining address, top, and impact of a swing from the measurement values; and selecting a shaft that matches a golfer through a usage of the swing characteristic amounts and values.

Abstract: A method of evaluating a golf club is disclosed. The method includes a step (St1) of determining motions of the golf club during a swinging motion of a golf player including a period ranging from a time (Ts) to a time (Tf); a step (St2) of obtaining in a time series power index values (Pw) during the period ranging from the time (Ts) to the time (Tf), based on the result of the determination; a step (St3) of obtaining a power integration value (Sp) by integrating the power index values (Pw) during the period ranging from the time (Ts) to the time (Tf); a step (St4) of calculating club energy (Eg) of the golf club at the time (Tf); and a step (St5) of quantitatively evaluating club suitability based on the power integration value (Sp) and the club energy (Eg). Each of the power index values (Pw) is a value which is correlated to a power of a work provided from the golf player to the golf club.

Abstract: An analysis method of the present invention includes the steps of: measuring a swing of a golf club to which a sensor capable of measuring accelerations in directions of three axes and angular velocities or angles about the three axes is attached; obtaining an index for classifying the swing based on a measuring result of the sensor; and classifying the swing based on the index. The index includes the following item (a) or (b): (a) a grip angular velocity at least at one time during a downswing; and (b) a grip velocity at least at one time during the downswing. Preferably, times of an address, a top, and an impact are determined in the analysis method.