A practice device includes a base, a support tube, a post, an axle, a first ball rod, and a brake. The support tube extends upward from the base and has a support tube longitudinal axis. The post extends from the support tube and has a first portion and a second portion. The first portion is engaged with the support tube and the second portion includes a first arm. The axle is coupled to the first arm and has a rotation axis. The first ball rod is coupled to a first practice ball and extends between the first practice ball and the axle. The first ball rod is coupled to a first practice ball and extends between the first practice ball and the axle. The first ball rod is configured to rotate about the rotation axis of the axle and when the first ball rod rotates about the rotation axis of the axle, the first practice ball contacts the brake to slow rotation of the first ball rod.

A method of manufacturing a string 10 for use in a racket includes: (A) preparing an untreated string; and (B) irradiating the untreated string with radioactive rays. Preferably, the untreated string is irradiated with gamma rays. A preferable irradiation amount of the radioactive rays is greater than or equal to 250 kGy but less than or equal to 2000 kGy. Preferably, a material of the untreated string is polyester. Alternatively, the material of the untreated string may be nylon.

A pulling string apparatus of a stringing machine comprising a string gripper, a sensor, a drive element, a transmission mechanism and a control circuit; the sensor is connected with the string gripper to detect the pull force of the string gripper; the control circuit compares the detected pull force value with a pre-set value, and control the rotation of the drive element; the transmission mechanism comprises a mounting base, a sliding block, a transmission rack and a drive gear; wherein the drive gear is connected to the drive element and is engaged with the transmission rack, the sliding block arranged on the transmission rack is connected with the sensor; when the sensor and the string gripper are driven forward or backward by the sliding block under the act of the transmission rack engaged with the drive gear, the racket string will be tensioned or loosened.

A grip device for a racket includes at least two externally protruding bodies, a primary body and a secondary body, extending from the outer surface of the racket handle and being located circumferentially distanced from each other. The racket handle has a central longitudinal axis A, wherein the primary body is of a quadrilateral or triangular construction.

It is disclosed a method, and a system (30) capable of localizing ball hit events on a sports court. From on acoustics data acquired (22) of ball hit events by individual distributed sensors or microphones, ball hitting patterns are identified (24) in the data from each individual sensor. Based on the identified ball hitting patterns and geometric constraints of a sports court and the distribution of sensors, ball hit events are detected (26). The localization of the detected ball bit events is determined (28) based on the geometrical constraints of the sports court and the sensor distribution. The system has a number of advantages of which some are that it is cheap to install, it is non-invasive, and that it can easily be extended to provide higher precision of ball hit event localization.

Training equipment includes a hollow shaft having a sidewall defining an internal cavity and at least one polymer material filling at least a portion of the internal cavity. The polymer material may fill the entire internal cavity of the hollow shaft. The polymer material may be a visco-elastic polymer material or polyurethane. A spacer or a filler may fill at least a portion of the internal cavity. A method of making weighted training equipment with a hollow shaft having a sidewall defining an internal cavity may include injecting a curable composition into at least a portion of the internal cavity. The method may further include curing the curable composition into a polymer material.

The present invention relates to a ball game racket frame with a head portion and a handle portion, wherein the ball game racket frame comprises a fiber composite with at least one multi-fiber roving that is at least partially twisted.

An apparatus configured to launch balls may include a container configured to hold a plurality of balls; a plurality of launchers, each of the launchers configured to launch balls to a different location; and a controller configured to launch balls according to a pattern.

A racket includes: a grip; an annular frame; and a shaft coupling the grip and the frame together; wherein a projection is provided to an outer peripheral face on a leading end half of the frame in a predetermined range including a location of maximum curvature in a peripheral direction.

A sports training/exercise apparatus attached to a swinging sports apparatus, typically a racquet and most specifically a tennis racquet. The apparatus includes a drag chute with a rigid member disposed therearound and a clamp secured to each side of the drag chute. A transverse support rod is positioned between the clamps and includes an aperture therein. The apparatus further includes brackets at the top and bottom of the racquet head. A longitudinal support rod is positioned between the brackets and extends through the aperture in the transverse support rod. Thus, the transverse support rod, the side clamps, and the drag chute are slidable along the longitudinal support rod to adjust resistance. A locking mechanism can be used to lock the transverse support rod in a position along the longitudinal support rod.