A system for monitoring cyclical movements of the lower body of a user undertaking a physical activity and providing feedback to the user has a first sensor arrangement 14 incorporated within at least one garment which is configured to detect at least one biomechanical parameter relating to the angle of at least one ankle joint of the user. Alternatively or in addition the system has a second sensor arrangement 16 configured to detect at least one biomechanical parameter relating to the motion of the pelvis of the user. The system also includes a processing unit 20 which is configured to receive information on the biomechanical parameters, to calculate a performance metric, and to provide performance-related feedback to the user. The system may detect the orientation of a foot of a user the activity may be cycling, swimming or a resistance exercise.
