Joints CONTINUALLY send messages to RECEPTORS (sense organs) that “tell” your brain exactly what is happening at the joint. IF a joint is not functioning IDEALLY, it tells your brain.° Then your brain either recruits or DOES NOT RECRUIT Muscles in a usual (NORMAL) manner, because well, the joint “ain’t right.” Physical therapy is very important for muscles, especially after surgery. HOWEVER, many Surgeons now realize that unless the JOINTS are addressed, their surgical work (on a shoulder for instance) will NOT have IDEAL OUTCOME, as the muscles depend on signals from the JOINTS for IDEAL functioning.
°NOTICE that this does NOT (necessarily) “hurt.” Incorrect function (“dysfunction”) is not always painful, eventually – likely, but often not immediately. 😉