thanks.. the vet did do some tests on him, moving his back legs, feeling down his spine etc..so was probably thinking the same thing. Do you think this tightness will go away with time and therapy like you mentioned. I would hate to have him on muscle relaxants indefinitely. He does seem to have weakness in his back legs - walks gently on them and wobbly a bit like before and wants to plop down and sit alot - similar to before surgery. Hopefully it is the muscle thing and he can improve..