According to the flight instructor, he and the student pilot flew to a local airport to practice touch and go landings and takeoffs. The student pilot flew the traffic pattern uneventfully, and during the final approach to land, the airspeed was excessive. The airplane touched down, and bounced back into the air; the student pilot regained control of the airplane, and touched down in the proper landing attitude. During the landing roll the airplane began to drift to the right, and the flight instructor called out for left rudder input while engaging the left rudder pedal. According to the student pilot, he initiated more right rudder pedal force and caused the airplane to ground loop. The airplane struck a runway sign and sustained substantial damage to the fuselage. Both pilots reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.