Beny bones are quite handy when moving cord-like legs. But you can by bending and stretching make the legs longer. I want to keep the length of the legs of my character constant at all time.
Is there a way to keep the length constant?
So it kan be stretched for bending and moving but no added length?
the handle bones of the bendy bone are not usually used for keying animation . Those are usually a sub-rig to modify the deformations but the animation chain should remain a simple two bones chain.
Then you constraint your handle bones to the Fk chain.