The flight instructor and student pilot were practicing crosswind landings in the traffic pattern. On the first landing attempt, the student pilot crabbed into the wind and as the airplane was over the runway, he applied left aileron in order to straighten the airplane over centerline and the flight instructor called to perform a go around maneuver. While in the traffic pattern, the flight instructor explained that using the rudder was normal practice to straighten out the airplane instead of the aileron and to try again on the second landing. During the second landing attempt, the student applied left rudder to straighten out over runway centerline. Before the airplane touched down, he added more left rudder. Again, the flight instructor called to perform a go around maneuver, however, the wheels touched down and the airplane bounced to the left. The student pilot applied full engine power and the airplane veered to the left. The flight instructor took over the flight controls and attempted to correct the turn by applying right rudder, however the airplane continued to drift to the left. The airplane continued off the side of the runway and impacted the ground, resulting in the nose landing gear collapsing and the empennage partially separating from the airplane. The airplane slid and came to rest on a taxiway. The airplane incurred substantial damage to the empennage. After the accident, the flight instructor remarked that the student pilot might have had his foot on the left rudder, which may have been why the instructor's right rudder input was not sufficient. Furthermore, a Federal Aviation Administration inspector asked the student pilot if he released the left rudder when the flight instructor took control of the airplane and he noted that he was unsure, since the accident sequence happened so quickly. The flight instructor reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation.