The exercise for the student was to be an engine failure on take off before the decision speed of 88 knots. On take off the engine was failed at 80 knots. The student re-acted incorrectly and lifted the aircraft off, instead of closing the throttles and rejecting the take off. The instructor took control, closed the throttles and landed the aircraft on the runway. As the aircraft slowed an uncontrollable swing right developed and the aircraft came to a stop to the right of the runway. Inspection of the aircraft showed that the right main gear leg had collapsed. The upper section of the gear leg had split and allowed the lower section to detach. The damage was consistent with a heavy touch down on the right gear leg. On abserver reported that the aircraft appeared to descend rapidly to the runway from a height of about 30 feet, touching down on the right gear leg first. Significant Factors The following factors were considered relevant to the development of the accident: 1 Unexpected reaction by the pilot under check in lifting the aircraft off when the speed was below the decision speed. 2 Heavy touch down on right main gear leg, following instructor actions when he took over at a low airspeed.