Small Multifidus Muscle Size Predicts Football Injuries

BACKGROUND: In Australian football, lower limb injuries have had the highest incidence and prevalence rates. Previous studies have shown that football players with relatively more severe preseason and playing season hip, groin, and thigh injuries had a significantly smaller multifidus muscle compared with players with no lower limb injuries. Rehabilitation of the multifidus muscle, with restoration of its size and function, has been associated with decreased recurrence rates of episodic low back pain and decreased numbers of lower limb injuries in football players. Assessment of multifidus muscle size and function could potentially be incorporated into a model that could be used to predict injuries in football players. PURPOSE: To examine the robustness of multifidus muscle measurements as a predictor of lower limb injuries incurred by professional football players. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Ultrasound examinations were carried out on 259 male elite football players at the start of the preseason and 261 players at the start of the playing season. Injury data were obtained from records collected by the Australian Football League (AFL) club staff during the preseason and the playing season. RESULTS: Decreased size of the multifidus muscle at L5 consistently predicted injury in the preseason and playing season. Asymmetry of the multifidus muscle and low back pain were significantly related to lower limb injuries in the preseason, and having no preferred kicking leg was related to season injuries. Seasonal change in the size of the multifidus muscle indicating a decrease in muscle mass was linked to injury. Sensitivity and specificity of the model were 60.6% and 84.9% for the preseason and 91.8% and 45.8% for the playing season, respectively. CONCLUSION: A model was developed for prediction of lower limb injuries in football players with potential utility for club medical staff. Of particular note is the finding that changes in muscle size from the preseason to the playing season predicted injury. CLINICAL RELEVANCE: As size of the multifidus muscle has been shown to be modifiable with training and has been associated with reduced pain and occurrence of injuries, this information could be incorporated in current programs of injury prevention.