Muscle editor is a macroscript for making a true use of the bone scale/squash options in your rigs.
When running the script you'll recive an interface - here is a sample example of how you work with it:
-Hit the first button and select all the bones' tips (those tips will be freezed and thei parent will become stretchy).
-Select the type of scale you desire - scale/squash.
-Hit the squash it button and you're done.
* the last set of buttons are simple tools for managing your muscles (change from type to type and reset the stretch).
Original script created by Yoni Cohen