Abstract: A measurement system includes a first measurement unit configured to measure floor reaction forces of golfer's left and right legs, a second measurement unit that is attached to the upper body of a golfer and configured to measure an angular velocity of the golfer, and a processing unit. The processing unit calculates, based on measurement results of the first measurement unit and the second measurement unit, a first energy which is a kinetic energy of the golfer during a swing.

Abstract: A measuring system includes a first measuring unit configured to be attached to a golfer, a second measuring unit configured to measure a floor reaction force of each of left and right leg portions of the golfer, and a specifying unit configured to specify a swing start timing of the golfer based on measurement results of the first measuring unit and the second measuring unit.

Abstract: A measurement system includes a first measurement unit configured to measure floor reaction forces of golfer's left and right legs, a second measurement unit that is attached to the upper body of a golfer and configured to measure an angular velocity of the golfer, and a processing unit. The processing unit calculates, based on measurement results of the first measurement unit and the second measurement unit, a first energy which is a kinetic energy of the golfer during a swing.

Abstract: A golf club includes a shaft; a head mounted to the tip end of the shaft; a grip mounted to the butt end of the shaft; a first vibration damping member arranged on the head side of the shaft; and a second vibration damping member arranged on the grip side of the shaft. The first range of the shaft in which the first vibration damping member is arranged includes a position of the shaft corresponding to the top end of the hosel of the head and has a length of 25 to 250 mm in the longitudinal direction of the shaft. The second range of the shaft in which the second vibration damping member is arranged includes a position of the shaft corresponding to the tip end of the grip and has a length of 150 to 250 mm in the longitudinal direction of the shaft.

Abstract: The present invention provides a golf club shaft. The shaft is made of a fiber reinforced resin. When a position 100 mm apart from a distal end of the shaft is represented by P1, a position 200 mm apart by P2, a position 500 mm apart by P3, and a position 1,000 mm apart by P4, thicknesses at the positions are defined as P1: not more than 1.0 mm, P2: not more than 0.9 mm, P3: not more than 0.6 mm and P4: not more than 0.6 mm. Each section between the positions has a thickness larger than a thickness transition obtained by connecting the thicknesses at the positions by a straight line. The shaft includes a plurality of prepregs which include first prepregs containing carbon fibers and a second prepreg containing a high specific gravity material.

Abstract: The present invention provides a golf club shaft. The shaft is made of a fiber reinforced resin. When a position 100 mm apart from a distal end of the shaft is represented by P1, a position 200 mm apart by P2, a position 500 mm apart by P3, and a position 1,000 mm apart by P4, thicknesses at the positions are defined as P1: not more than 1.0 mm, P2: not more than 0.9 mm, P3: not more than 0.6 mm and P4: not more than 0.6 mm. Each section between the positions has a thickness larger than a thickness transition obtained by connecting the thicknesses at the positions by a straight line. The shaft includes a plurality of prepregs which include first prepregs containing carbon fibers and a second prepreg containing a high specific gravity material.

Abstract: A golf club includes a shaft; a head mounted to the tip end of the shaft; a grip mounted to the butt end of the shaft; a first vibration damping member arranged on the head side of the shaft; and a second vibration damping member arranged on the grip side of the shaft. The first range of the shaft in which the first vibration damping member is arranged includes a position of the shaft corresponding to the top end of the hosel of the head and has a length of 25 to 250 mm in the longitudinal direction of the shaft. The second range of the shaft in which the second vibration damping member is arranged includes a position of the shaft corresponding to the tip end of the grip and has a length of 150 to 250 mm in the longitudinal direction of the shaft.