The flight instructor and student pilot were conducting a training flight that included touch and go landings. During landing rollout, with about 2,000 ft of runway remaining, the flight instructor directed the student to transition to a soft field takeoff.The student made the takeoff and attempted to climb out of with a high pitch attitude, during which the airplane settled back to the ground off the end of the runway. The airplane subsequently impacted a ditch, which damaged the fuselage. Following the accident, the flight instructor recognized the pitch attitude during the student's climb out was too high and that he should not have directed the student to attempt a soft field takeoff, based on the runway distance remaining. The accident report form indicated that there were mechanical malfunctions or failures that would have precluded normal operation.