An exerciser includes a safety block having two through holes defined through the safety block and two cutouts defined in two opposite sides of the safety block, two elastic strings respectively extending through and securely received the two through holes of the safety block, two safety pads each provided to opposite sides of the safety block to securely connect to one end of the two elastic to allow an operator to work on thigh muscles and two rings connected to a corresponding one of the two safety pads to allow the operator to work on chest muscles.