A signaling device, and in particular a signaling device for a striking implement such as a tennis racket, a golf club or the like, for generating signals during a movement of the signaling device (10), including a resonant body and a holding device, wherein the resonant body and the holding device are to be connected to one another or connectable to one another, so as to attach the resonant body by way of the holding device to a striking implement or the like, wherein the resonant body furthermore includes a cavity for generating an acoustic signal during a movement, wherein the resonant body has a single opening which has a fluidic operative connection to the cavity and by way of which the cavity is fluidically connected to the surrounding area.

A golf club training device including: a body having a first end configured to be gripped by a user and a second end longitudinally extended from the first end; and a swing speed sensor disposed at the second end for producing an output signal for determining a portion of a golf swing having a greatest swing speed. A golf club training system is also provided to include: a plurality of the golf club training devices wherein at least two of each of the plurality of golf club training devices having one or more of a different weight and length.

A swing speed training club includes a shaft having a proximal end and a distal end; and a head portion affixed to the distal end of the shaft and having a body having a proximal end and a distal end. The head portion is configured to produce a distinctive sound when the head portion is swung through the air at the distal end of the club shaft at a suitable speed.

A method for analyzing sensor data from baseball swings (or swings in similar sports) that transforms data into a reference frame defined by the bat orientation and velocity at impact. The trajectory of the sweet spot of the bat is tracked through the swing, and is analyzed to generate metrics describing the swing. A two-lever model of the swing may be used to model the effects of body rotation and wrist rotation. Data may be analyzed to identify relevant events during the swing such as start of downswing, commit (wrist release), on-plane, peak bat speed, and impact. Illustrative swing metrics derived from the sweet spot trajectory, the swing plane reference frame, and the two-lever model include: forward bat speed, on-plane rotation, hinge angle at commit, hinge angle at impact, body rotation ratio, body tilt angle, and swing plane tilt angle.

A cavity back iron type club head includes a striking plate having a substantially planar striking surface and a rear surface defining a thickness therebetween. The rear surface defines a striking plate rear cavity region. A perimeter support is coupled to a peripheral portion of the striking plate. The surface area of the striking surface is related to the club head loft angle by the equation SSA14.4(L)+2875, where SSA is the surface area of the striking surface in units of square-millimeters and L is the club head loft angle in units of degrees.

A golf training aid 20 that provides to the user unmistakable positive feedback how to use the hands, wrists and forearms in the golf swing to affect what has been popularly called Ben Hogan's Secret Move, particularly during the transition of the golf swing. Golf training aid 20 also provides the golfer unmistakable feedback as to whether they have executed the correct movement that Hogan explained in his 1955 Life magazine article.

A golf training device with audio and visual/touch cues for independent golf swing training in an absence of a golf instructor includes a tube having a first end and a second end and an outer surface. A hand grip is disposed at least in part about the outer surface of the tube. A sliding mass is disposed slidingly within the tube, the sliding mass including a chamfer on at least one end of the sliding mass. A ball holding rod is mechanically coupled to the second end of the tube has a ball hold rod first end and a ball hold rod second end. A ball is mechanically coupled to the second end of the ball holding rod. A club head stem extends into a club head, the club head stem is mechanically coupled to the first end of the tube to rigidly affix the club head to the tube.

A cavity back iron type club head includes a striking plate having a substantially planar striking surface and a rear surface defining a thickness therebetween. The rear surface defines a striking plate rear cavity region. A perimeter support is coupled to a peripheral portion of the striking plate. The surface area of the striking surface is related to the club head loft angle by the equation SSA14.4(L)+2875, where SSA is the surface area of the striking surface in units of square-millimeters and L is the club head loft angle in units of degrees.

A method for analyzing sensor data from baseball swings (or swings in similar sports) that transforms data into a reference frame defined by the bat orientation and velocity at impact. The trajectory of the sweet spot of the bat is tracked through the swing, and is analyzed to generate metrics describing the swing. A two-lever model of the swing may be used to model the effects of body rotation and wrist rotation. Data may be analyzed to identify relevant events during the swing such as start of downswing, commit (wrist release), on-plane, peak bat speed, and impact. Illustrative swing metrics derived from the sweet spot trajectory, the swing plane reference frame, and the two-lever model include: forward bat speed, on-plane rotation, hinge angle at commit, hinge angle at impact, body rotation ratio, body tilt angle, and swing plane tilt angle.

A golf club head comprises a sole, a recessed sole port in the sole; and a rotatably adjustable sole piece adapted to be at least partially received within the sole port and comprising a central body having a plurality of contact surfaces adapted to contact the sole port and being offset from each other along a central axis extending through the central body of the sole piece. The sole piece can be positioned at least partially within the sole port at five or more rotational and axial positions with respect to the central axis, wherein at each rotational position, at least one of said contact surfaces of the central body contacts the sole port to set the axial position of the sole piece. The sole port and/or the sole piece can be generally pentagonal in shape.