The rear-seated student pilot was taking off in the experimental light sport weight-shift control airplane with a flight instructor seated in the front seat. According to the flight instructor, the aircraft lifted off the runway and began to drift to the left toward an airport windsock. He told the student pilot that he was assuming control and attempted to correct the flight path and climb, but the student pilot remained frozen on the control bar. The control bar pressure then reversed, and the aircraft suddenly pitched up rapidly, stalled, and impacted the ground left wing first. The aircraft sustained substantial damage to the left wing. The student pilot stated that he remained on the controls during the entire accident sequence and he was not aware that the flight instructor was attempting to assume control of the aircraft. Neither pilot reported any mechanical malfunctions during the flight. The flight instructor reported 308 hours of total flight experience, which included 17 hours in the same make and model as the accident aircraft. The student pilot reported that he had previously held a private pilot certificate and accumulated about 175 hours in single-engine airplanes, but he had not actively flown for about 24 years. At the time of the accident, he had accumulated about 5 hours in weight-shift control aircraft.