Knee Mechanics, Strength and Flexibility: Assessing Injury Risk in Female Adolescent Soccer Players

Background/Objectives: This study examined the link between the Q angle, knee hyperextension, flexibility, strength profiles and injury occurrence in female adolescent soccer players. Methods: Thirty adolescent female soccer players (age range: 15-17 years; age: 15.47 +/- 0.73 years; weight: 55.91 +/- 7.44 kg; height: 160.01 +/- 5.58 cm) were recruited for the study. The tests were conducted before the pre-season preparation period, and the players were monitored from the beginning to the end of the season. This study included players who sustained non-contact injuries throughout the season as well as those who did not sustain any injuries for comparison purposes. Players underwent an anthropometric assessment (height, weight, body fat, Q angle, knee hyperextension) and completed a sit-and-reach test and an isokinetic assessment at 60 degrees/s. Results: The results showed that 36.67% of players sustained a non-contact injury during the season. Based on the isokinetic assessment at 60 degrees/s, significant differences were observed between the two groups in the torque production of the right and left knee extensors [t(28) = 2.32, p = 0.03, d = 0.81 (large effect)] and the right and left knee flexors [t(28) = 2.04, p = 0.05, d = 0.71 (medium effect)], with the injured group demonstrating significantly greater interlimb asymmetries in torque between the right and left knee extensors, as well as the right and left knee flexors. Also, the injured group demonstrated significantly higher knee hyperextension values for both the right [t(28) = 6.12, p < 0.05, d = 2.22 (large effect)] and left legs [t(28) = 5.72, p < 0.05, d = 2.15 (large effect)]. Conclusions: interlimb asymmetries and knee hyperextension may contribute to the occurrence of lower body non-contact injuries in adolescent female soccer players.