A game ball is instrumented with a transducer to measure the impact forces on the ball andor the decelerations by the ball experienced during an attempted catch by a person. The main envelope has, beneath the shell, a plurality of perforations for placing the main enclosure in communication with the secondary enclosure. A flange is fixed to an end of the shaft. The transmitter can be configured to transmit data related to the mechanical deformation. An axial center position of the beam is shifted from an end face position of the step of the tie rod at least toward an axis center of the tie rod.