What happened
The pilot completed the landing under calm wind conditions. While the initial portion of the landing roll proceeded without incident, the aircraft began to drift toward the side of the runway as it decelerated.
In an attempt to correct the drift, the pilot applied corrective actions; however, the soles of his boots became caught on either the rudder pedals or against each other. This prevented the pilot from making necessary corrective rudder inputs for a period of time. By the time the pilot was able to free his feet, the aircraft had entered a ground loop that could not be recovered. During the continued ground loop, the aircraft departed the side of the runway and encountered soft terrain, which caused the aircraft to nose over.