Do you want to have both legs mirrored this way?  That is, can the poses simply be flipped, so frames 1-15 are the same as 16-30, but flipped left ro right?  Or just the one leg?

===========================sigline======================================================

Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.