A body part movement detection system and method, for use in training for a sport in carrying out a swing in a target direction, includes a transmitter configured to transmit signals over the course of the swing, using a form of radiation consisting of acoustic and electromagnetic, a first detector configured to receive the signals from the transmitter and to produce a first output related to a first distance of the body part to a first reference location, a controller configured to receive successive first outputs from the detector and to evaluate the successive first outputs in relation to at least one previous first output, to determine whether the body part has experienced motion having a component in the target direction by an amount in excess of a threshold, and an alert system configured to generate an alert to the user when the body part has experienced such motion.
