Patent ID: 9630066
Date: 2017-04-25
CPC Classifications: A61B,A63B

Claim:
1. A fitting method, of a shaft of a golf club, for selecting a shaft having a torque matching a golfer based on a swing of the golfer, the method including the steps of: obtaining measurement values from a sensor attached to a grip of the golf club and capable of measuring angular velocities about three axes when a golf ball is hit by the golf club; obtaining a predetermined index value for the angular velocities quantified from the measurement values; and selecting a shaft matching the golfer from among multiple shafts whose torques have been measured in advance, based on a relationship established through test-hitting performed in advance between the index value and a torque of a shaft, wherein, when x-axis is oriented in a direction along toe-heel direction of a golf club head, when y-axis is oriented in a direction in which a ball is hit, and when z-axis is oriented to match an axial direction of a shaft, the fitting method further includes the steps of: determining address, top, and impact of a swing from the measurement values; calculating t_ calculating ωx_ calculating, as the index value, a magnitude of a change amount of the grip angular velocity about the x-axis per unit of time by dividing the calculated ωx_ calculating the torque of the shaft from the calculated magnitude of the change amount of the grip angular velocity about the x-axis per unit of time, using an approximate formula that is prepared in advance through test-hitting and that expresses a relationship between a torque of the shaft and the magnitude of the change amount of the grip angular velocity about the x-axis.