Interpolate

Use the Spline Interpolation to automatically fill in missing points.  You can limit the size of the "gaps" by specifying the max gap size in frames.

Hint; This is a very useful tool when doing manual digitizing to cut down on the number of frames you need to digitize.  Set the Step Length so you only digitize every 2 to 10 frames depending on the motion.  Once you have digitized the selected frames, simply interpolate the skipped frames and let the spline interpolation do the digitizing for you. 

Spline Interpolation Dialog