Abstract: A racquet sport training device, including a housing with an exterior surface and an attachment portion arranged to engage a plurality of strings of a racquet such that the exterior surface is engaged with at least one string of the racquet The device includes a sensor assembly disposed within the housing and having: a vibration sensor engaged with the exterior surface; a computer electrically connected to the vibration sensor; and a user interface electrically connected to the computer. The vibration sensor is arranged to detect a vibration at the exterior surface. The computer is arranged to record each occurrence of the vibration.