Put muscles that are contracting into a stretch position that can be comfortable long term.
For me this is lying down. 
For lower back, I will lie on my side and assume the curled up position with knees close to chest.
In this position the muscle will try to contract as usual but now the muscle will face considerable resistance to pulling due to being in the stretched position.
After some time the muscle will run out of available energy and will slowly release.
This may have to happen several times before the muscle memory is lost and the muscle stops pulling long term.