Some further precautions are advised. In patients who have known severe
cardiovascular or pulmonary disease, initial supervision by a physical therapist or
nurse may be warranted, using blood pressure, pulse, and saturation by pulse
oximetry (SpO2) monitoring. Patients who have knee pain from severe OA may
benefit from strength training, but weight-bearing exercises may worsen symptoms
where knee malalignment and ligamentous laxity are evident [41]. Non–
weight-bearing exercises or water-based programs may be a better initial prescription
for these patients [42]. Patients with impairments such as cerebrovascular
accident or multiple sclerosis, which affect muscles and motor neurons,
may experience easier fatigue in these distributions. Strengthening is still beneficial
to these patients but may need to be introduced and advanced more slowly.