A device for training the muscles used during a golf club swinging motion. The device includes a connector coupled to the head of the golf club and a resilient and extensible tether having a proximal end for connection to the connector and a distal end for connection to a trainee's body. The device is used by causing the trainee to engage in a golf swing motion so that the tether provides resistance to the trainee's muscles in the sequence used to perform the swing.