animatinon frustration

as a novice blender(er) i was able to animate a rock flying through the air and then … trouble :no:. I want some one (in my blend) to punch this boulder in two or more pieces …but my rock is only a sphere with fractle being used … the video is not worth posting and sounds like an easy fix to some one who knows what there doing … so any help would be apreciated … thank you…

How about:

From the very beginning, break the rock mesh apart into separate objects (P key) but keep the parts in exactly the same positions so they still look like one rock. Move them all together from the beginning of the animation, keyframing each part and so giving each part its own IPO. At the point where the punch hits, start moving and keying the parts individually so they appear to fly off in different directions?