2-Rigid muscles
The musculoskeletal system is one of the most commonly affected in Parkinson’s disease. Muscles become tense and rigid, and patients often report stiffness in their articulations. When they undergo tests, they are all apparently fine and show no alteration because the origin of this alteration is nervous, not a problem in the muscle itself. It is an involuntary resistance against the movement and can be further divided into an oscillating resistance (which continuously comes and goes) or a smooth resistance (maintained with the same intensity throughout time).