This is an inflammation of “posterior tibial” muscle that runs on the inside of the calf along/behind the tibia bone. This muscle supports the arch and prevents over pronation or flattening of the arch. This injury is common in a person that has a pronated foot that rolls inward, weakness in the hip and core muscles which allow the knee and foot to collapse inward and sometimes a tight calf muscle. It will continue to get worse if the running activity continues. If left untreated, this injury may progress into a more serious condition in which the covering of the bone called the periosteum gets inflamed or if it continues into the bone a stress fracture can ensue. Early well rounded care is imperative to complete recovery.