The middle calf bone usually refers to the tibia, and the causes of vague pain may include strenuous exercise, tibia fatigue injury, tibia periostitis and so on. 1. Strenuous exercise: it may be caused by too much strenuous exercise, resulting in strains of calf muscles and ligaments, causing vague pain in the middle calf bone. 2. Fatigue injury of tibia: during long time walking and other sports, due to excessive force, it will cause fatigue injury of tibia, which will lead to vague pain in the middle calf bone. 3. Tibial osteochondritis dissecans: Hidden pain in the middle calf bone may be caused by tibial osteochondritis dissecans. As a result of prolonged walking or localized bumps and bruises, it is easy to cause aseptic inflammation of the periosteum, leading to tibial osteochondritis dissecans. There may also be other reasons for the pain in the middle calf bone, it is recommended to go to the hospital in time, complete the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.