Content area
Full Text
Introduction
Muscle injury is the most common injury type in football. 1-4 Quadriceps muscle strains frequently occur in sports that require repetitive kicking and sprinting efforts and are common in football in its different forms around the world. 1 5-7 The rectus femoris is the most commonly injured muscle of the quadriceps muscle. 7-11
The mechanism of lower extremity muscle injuries in football remains to be fully elucidated. The incidence of injury varies across the season; a higher risk of posterior thigh muscles exists during the in-season, 1 12 while rectus femoris strains (29%) were more frequent than biceps femoris (11%) muscle injuries in the pre-season of the English Premier League 13 and the Australian Football League. 7 In contrast, Ekstrand et al found that quadriceps muscle strains were fairly constant throughout the season. 1 Quadriceps muscle injuries cause more missed games than do hamstring and groin muscle injuries, 1 and reinjury rates (17%) are high. We reviewed the literature on rectus femoris muscle injuries and discuss the underlying biomechanical mechanisms and risk factors with a view to injury prevention.
Anatomy
Anatomy appears to play an important role in quadriceps muscle prognosis. The rectus femoris is a fusiform and biarticular long muscle located in the anterior aspect of the quadriceps muscle, these types of muscles are designed to execute movements that require significant length change or high shortening velocity. This biarticulate muscle is innervated by the femoral nerve and has two heads of origin: the direct or straight head, which arises from the anterior inferior iliac spine, and the indirect or reflected head, which arises from the superior acetabular ridge ( figure 1 ). 14 15 The two heads form the conjoined tendon slightly below their origin. The direct head contributes mostly to the superficial component of the conjoined tendon and blends anteriorly with the muscle's fascia. 14 The indirect head contributes to the fibres of the deep, intramuscular component of the conjoined tendon and forms a deep myotendinous junction that extends downward approximately two-thirds of the muscle belly of the rectus. 14
The rectus femoris extends the knee, flexes the hip and stabilises the pelvis on the femur in weight-bearing. 15 16 In addition, the rectus femoris has a high demand for eccentric muscle...