Difference between reciprocal inhibition and regular muscle movement? I was looking into a condition I have, anterior pelvic tilt, quite a bit. I ran into a website describing part of the issue as reciprocal inhibition. This was my confusion: Reciprocal inhibition, defined by just about everyone, is the relaxation of muscles antagonistic to muscles currently contracting, and vice versa. How is this different from regular muscular flex? When we flex a muscle, don't the antagonistic muscles relax to compensate, same as in reciprocal inhibition? Thanks.

> What is the difference between reciprocal inhibition and regular muscle movement?

Reciprocal inhibition is _part_ of regular muscle movement. It is controlled by the stretch reflex controlled by the muscle spindle. It's an important part of a functioning muscle and spinal cord, and not pathologic at all. However, this same reflex, in an excessively tight muscle on one end of a joint, would cause an excessively loose muscle on another end of a joint.

Here is an image showing this reflex, from Brust Practice of Neural Science, Chapter 6. ![enter image description here](

I can't give you any medical advice on this site, so I can't put that in context, but I think that answers your biology question.