Abstract: A system and method for monitoring the running technique of a user undertaking a physical activity is described. The system comprises: a garment worn by the user incorporating a sensor for the detection of a parameter relating to the movement of the pelvis of the user; a processing unit configured to receive information about the parameter from the sensor, to compare the parameter with an aspect of a biomechanical model, and to determine if a feedback response is required; and means for providing the feedback response to the user. The method comprises the steps of: measuring a parameter relating to the movement of the pelvis of the individual; comparing the parameter with a biomechanical model to determine whether a feedback response is required and providing a feedback response if required.