Risk factors for leg injuries in female soccer players: a prospective investigation during one out-door season

The following possible risk factors for leg injuries in female soccer playe rs were studied: age, anatomical alignment, generalized joint laxity, thigh muscle torque, muscle flexibility, ligamentous laxity of the knee and ankl e joints, recent injuries, and duration of soccer exposure. A total of 146 players from 13 teams in the second and third Swedish divisions underwent c linical examination, isokinetic measurements of quadriceps and hamstring to rques, and testing of postural sway of the legs. All soccer-related leg inj uries resulting in absence from at least one scheduled practice session or game were recorded during one outdoor season (April-October). In 50 players there were 61 traumatic injuries, and 17 players sustained 19 overuse inju ries. The overall injury incidence rate (traumatic and overuse) was 5.49/10 00 h of soccer. Variables significantly increasing the risk of traumatic le g injuries included generalized joint laxity, low postural sway of the legs , hyperextension of the knee joint, and a low hamstring-to-quadriceps ratio during concentric action. Multivariate logistic regression showed hyperext ension of the knee joint, a low postural sway, reduced H/Q ratio during con centric action, and a higher exposure to soccer to significantly increase t he risk of traumatic leg injury. All five players who suffered an anterior cruciate ligament injury during the study period had a lower hamstring-to-q uadriceps ratio during concentric action on the injured side than on their noninjured side.