Bridgestone Sports Co., Ltd.

Tomotaka Ishihara

Fumiaki Sato

Wataru Ban

Souichirou Sugawara

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.

Measurement system and measurement method

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.

Golf club

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 P, a position 200 mm apart by P, a position 500 mm apart by P, and a position 1,000 mm apart by P, thicknesses at the positions are defined as P: not more than 1.0 mm, P: not more than 0.9 mm, P: not more than 0.6 mm and P: 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.

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Chichibu, Japan

Tomotaka Ishihara