“…Of these, the most widely accepted maintains that PPS is the result of the gradual degeneration of motor units and the loss of the precarious balance between denervation and compensatory reinnervation [2,4,13,14,42,49]. In contrast, others hold that it stems from the influence of physiological neuronal loss in aging on a motor unit clinically or subclinically deteriorated by the enterovirus [12,24]; the triggering of a number of immunologic mechanisms [4,6,10,42]; poliovirus action [47,50,51]; or even that the symptoms and functional deterioration of polio survivors are due to orthopedic problems, biomechanical alterations and muscle overuse during the so-called period of stability and to which must be added the effect of additional neurological processes and other acute or chronic processes related to the ages of the victims [8,15,22].…”