Abstract: A muscle-back iron golf club head includes a blade-like upper mass, a muscle-like lower mass, a planar front surface, a top surface, a sole surface, a heel surface, a toe surface, and a rear surface having a first contour. A recess is in the rear surface, the recess having a first portion in the blade-like upper mass and a second portion in the muscle-like lower mass. An insert may be provided in the recess, and such insert may substantially fill the recess and may include a back surface having a second contour which is different from the first contour of the club head rear surface.

Abstract: A hollow golf club head having face end and tail ends, a strike face at the face end, a crown, a sole of length >3.5 inches, volume 0.300 cm3, and a structural response modifying constraining member having first and second ends, the second being forward of the first and spaced from the strike face, the contraining member extending vertically and in contact with the sole and the crown at its first and second ends, and extending horizontally a maximum distance that is <40% of the sole length, when the club head is in address position.

Abstract: A golf club head according to one or more aspects of the present invention may include a main cavity having at least one auxiliary cavity and a base surface. An insert may be associated with the base surface and may comprise at least two contact elements, with a bridge member disposed therebetween. Different contact elements of the insert may be disposed in separate respective auxiliary cavities, such that each contact element may be associated with the base surface. The bridge member of the insert may be dissociated from the base surface. Moreover, a surface coating may be selectively applied to the head to permit a durable adhesive bond between the insert and the base surface.

Abstract: A golf club head includes a striking face having a face center, a bottom portion, a top portion including an exterior surface, a hosel including an imaginary vertical hosel plane, a forwardmost point, and a rearwardmost point. In an imaginary vertical plane perpendicular to the hosel plane and passing through the face center, the exterior surface includes a path having a first point and a second point rearward of the first point. An imaginary infinite straight line passes through the first point and the second point, but does not penetrate the exterior surface. A segment of the imaginary straight line is delimited by the first point and the second point. A maximum distance between the segment and the exterior surface of the top portion is no greater than 0.70 mm and a distance between the first point and the second point is no less than 22 mm.

Abstract: A golf club head includes a striking face having a face center, a bottom portion, a top portion including an exterior surface, a hose1 including an imaginary vertical hose1 plane, a forwardmost point, and a rearwardmost point. In an imaginary vertical plane perpendicular to the hose1 plane and passing through the face center, the exterior surface includes a path having a first point and a second point rearward of the first point. An imaginary infinite straight line passes through the first point and the second point, but does not penetrate the exterior surface. A segment of the imaginary straight line is delimited by the first point and the second point. A maximum distance between the segment and the exterior surface of the top portion is no greater than 0.70 mm and a distance between the first point and the second point is no less than 22 mm.

Abstract: A method of selecting a preferred golf shaft for a player who uses an existing golf shaft, according to one or more aspects of the present invention, may comprise gathering a plurality of empirical data sets, each data set corresponding to an individual golf shaft selected from a plurality of golf shafts; providing a plurality of specification codes, each associated with an individual empirical data set of the plurality of empirical data sets; from the plurality of specification codes, identifying a first specification code associated with the existing golf shaft; gathering feedback associated with the existing golf shaft from the player; and using the feedback to select, from the plurality of specification codes, a second specification code corresponding to the preferred golf shaft.