Pain is an unpleasant reaction to a stimulus that functions as a defense mechanism to prompt the body to react quickly to protect itself. However, the body can activate an analgesic function to reduce pain. KAATSU training is a low-load, short-term exercise method that can induce increased muscle strength and muscle hypertrophy, for which domestic studies have reported pain-relieving effects. In this review, we present a case series of patients with idiopathic osteonecrosis of the femoral head and idiopathic osteonecrosis of the femoral medial condyle, in whom improvements in chronic pain were achieved by KAATSU training. We further introduce the effects of training under blood flow restriction, KAATSU training, on pain relief, in addition to performing a literature review.