Embodiments of the present invention are directed to devices, systems, and methods for implementing drills and providing coaching instructions to users. Embodiments may load a drill, measure values obtained from one or more sensors installed on a player's tennis racket and/or worn on the player's body, and use those values to detect various parameters, such as the physical impact of a ball at the player's racket. Embodiments may then output a coaching instruction to the user. Embodiments may also include adding customized coaching instructions to a drill.