A method and system is therefore provided for fitting a set of golf clubs to a particular golfer. In particular, the club fitting method and system assists a golfer in the selection of a set of golf clubs by providing objective indicia or scores representative of the manner in which the golfer hits golf shots with each of a number of different golf clubs. The club fitting method and system provide the golfer with numerical values representative of the consistency and performance of the golf shots made with a particular golf club, typically on an automatic basis. Based upon the relative numerical values representative of the consistency and performance of the golf shots made with a number of different golf clubs, the golfer can select the set of golf clubs which provides the combination of consistency and performance that is best suited for the golfer's game.

The sole shape can be designed with ease. The invention provides a method for designing an iron sole shape that includes the steps of setting different parameter values (S1) relating to a sole shape while keeping parameters other than those of the sole shape constant, preparing an iron club (S2) having the parameter values that have been set, a tester using the iron club that has been prepared to hit a ball (S4), measuring a path of the club head (S5) using a camera to obtain data relating to a position and a velocity of the club head, and determining whether or not the sole shape is favorable (S6) based on the data that have been obtained.

A trial golf club and golf fitting system for determining at least one custom fitted golf club. The trial club includes a golf club head having a sole defined by a radius of curvature. The sole of the golf club head includes graduated indicia for identifying an optimal lie angle for the fitted club. When the golfer swings the trial golf club, the optimal lie angle of the fitted club is identified by locating the point of impact on the sole of the head of the trial golf club.

A swing measurement method of directly measuring a swing behavior without being influenced by flexure of an impact implement, such as a golf club or baseball bat is provided. In addition, a golf swing analysis method and computer program product having computer program code for a simple and effective model of the behavior of a grip portion during a golf swing is provided. A three dimensional magnetic sensor capable of measuring position and direction is fixed to a grip portion of the impact implement within magnetic fields in which the magnetic field distribution of intensity and direction are known, and the behavior of the swing is directly measured. In addition, the path of the grip portion is approximated as an arc within a swing plane using the three dimensional position coordinates of the grip portion obtained in this measurement, and thus an arm angle, a wrist angle, and an angle of shaft rotation are found. The time sequence data of the wrist angle and the time sequence data of the shaft rotation angle, with respect to the time sequence data of the arm angle are plotted and the swing behavior is analyzed.

A golf club head is provided having a substantially increased sweet spot across its club face. A preferred construction includes an annular area on a rear surface having increased thickness surrounding a central region with a balance point of the club face. The central region of the face has a generally reduced thickness that is less than the maximum of the annular area but greater than a minimum thickness at the peripheral area. The face material may be metallic, but in alternative embodiments the effective bending stiffness profiles represented by this annular area may be achieved by appropriate use of composites, for example. Methods for manufacturing a golf club head having a face with the bending stiffness profiles of the present invention include forging and machining techniques as well as laser deposition and inertia welding.