Core muscle injury, often misleadingly called a "sports hernia," is a condition that mainly affects athletes who play soccer, hockey, football, and rugby, and who run track. It is more common in males than females. A full 94% of these injuries occur gradually from unknown causes; the other 6% are caused by a specific traumatic incident

Stress from repetitive twisting, kicking, and turning at high speeds is a likely cause of injury.

Athletic pubalgia and sports hernia, but this injury does not fit the common definition of a "hernia," where an organ or soft tissue protrudes outside its normal cavity. There is no defect in the abdominal wall or herniation of the abdominal contents with a sports hernia. Injury occurs in the form of tears and weakening in the deep layers of the abdominal wall.

Repetitive hip and pelvic motions typical in sports can cause injury to the lower abdominal area. Imbalances between the hip and abdominal muscles can, over time, cause overuse and injury. Weakness and lack of conditioning in the abdominals also might contribute to the injury. Ironically, aggressive and unsafe abdominal exercise programs can also cause or aggravate a core muscle injury. A core muscle injury usually occurs where the abdominal muscles attach in your pelvis. There is no protrusion of organs, but there are tears in tendons and muscles, such as those surrounding the hip. This makes the term "hernia" a misnomer, as the term hernia means when organs from your abdomen come out through spaces, such as the inguinal canal. Nerve irritation can also occur, contributing to the uncomfortable symptoms.

Chronic groin pain is a hallmark symptom of core muscle injury. It occurs in 5% to 18% of athletes, and varies with the sport being played. Sharp groin pain with exertion is also a typical symptom. Pain often occurs exclusively with intense sprinting, kicking, twisting, or "cutting," and subsides rapidly with rest. Significant training and competition time can be lost due to related chronic groin pain.