Abstract: A golf stroke training apparatus is disclosed, comprising a light source attached to the chest of the golfer. Light shines towards a visible surface whereby observation of the light provides information about the movement of the chest. It can be deduced how the golfer generates movement of the club, with respect to elements such as rotation around the spine or movement at other joints, such as shoulders or hands. The apparatus can be particularly useful for putting but can also guide thoracic movement in other golf strokes. Optionally, a second device having a light source can be secured in relation to the pelvis of the golfer, for use separately or in concert with the chest mounted device.