NTSB Factual Report

According to the pilot, at the request of the aircraft's owner, he was flying with the passenger to help him become current as he had not flown any type of aircraft in the last 8 years. He was making a no-flap 3-point full stall landing with the passenger on the controls with him. During the landing roll, as the airplane slowed down, the pilot let some pressure off the rudder pedals to slide his toes up onto the brakes. As soon as the pressure was released from the rudder pedals, the airplane started to swerve "one way then the other." The pilot attempted to correct, but the airplane "spun a 180 degree turn to the left." The left wing tip and the right elevator struck the ground. The pilot reported that the passenger was wearing heavy boots and may have inadvertently "kicked hard right or left rudder and then became briefly entangled in the rudder pedals."

NTSB Probable Cause

the inadvertent use of the rudder by the passenger, which resulted in an inadvertent ground loop.