In preparation for an upcoming private pilot check ride, the student pilot was performing a simulated forced landing with his flight instructor. During the flare, the student abruptly pulled up on the collective and rolled the throttle the wrong way. The engine sputtered, then shut off. The instructor attempted to recover the engine, however insufficient altitude was available. The helicopter landed on the right skid and bounced, breaking off the tail boom. The instructor stated that there was no mechanical malfunction or failure with the helicopter during the accident sequence.