Leg dominance and ACL injuries in soccer players.

Gender influences: the role of leg dominance in ACL injury among soccer players. 
Brophy, R., Silvers, S., Gonzales, T. and Mandelbaum, T. Bristish Journal of Sports Medicine; 2010, 44, 694 – 697. 
http://www.ncbi.nlm.nih.gov/pubmed/20542974


Soccer is the most popular sport in the world and soccer injuries occur most frequently in the knee, ankle and groin. ACL tear is one of the most common injuries sustained by those participating in the sport. It has been suggested that leg dominance might play a role in aetiology of ACL injuries due to different muscle activation patterns seen in kicking vs. supporting leg and therefore different demands put on lower extremity. However there appears to be lack of research studying that. Moreover, one must take into consideration importance of gender discrepancies where ACL tears incidence is reported to be, at least, two times greater in females compared to males. Authors found out lack of literature looking at the potential relationship between leg dominance and ACL injury risk specifically in the soccer athlete. Therefore, purpose of the study was to look at the role of leg dominance in ACL injury risk among soccer athletes, particularly when adjusting for gender.
A total of 93 soccer players (N=41 male, 52 female) who had undergone ACL reconstruction were identified and consented to participate in this study. The mechanism of injury was divided into two categories: contact and non-contact. Results indicated that more than half of the ACL injuries occurred in the dominant lower extremity (53/99). Interesting finding was reported when to look at non – contact injuries specifically. When the data were stratified for gender, there was a significant difference in the distribution of non-contact injury with respect to dominance. Exactly 74.07% of males (20/27) were injured on the dominant kicking leg compared with 32.26% (10/31) of females.
In conclusion, when limited to a non-contact injury mechanism, female soccer athletes are more likely to injure the ACL in their preferred supporting leg whereas male soccer athletes tend to injure the ACL in their preferred kicking leg. Authors proposed some explanation to the phenomena observed. Males might be more prone to injure their kicking leg due to the imbalance that usually exists between the quadriceps and the hamstring in the sagittal plane and the adductor to abductor in the frontal plane. In addition, pelvic positioning can perhaps contribute to this phenomenon. During striking, pelvis tilts anteriorly on preswing, whereas, at the point of initial contact with the ball, pelvis assumes posterior tilt. At this point, the insertion for the biceps femoris musculature migrates caudally, thus alters the length tension relationship of the biceps femoris. The quadriceps has a mechanical advantage—and may impart a significant anterior shear force that precludes the ACL tear. In regards why females might be more prone to sustain an ACL injury in their supporting leg, literature presents several mechanisms including decreased core stability, knee valgus, decreased peak knee flexion angles upon jump – landing, decreased lateral hip control and slower contraction times. Valgus angles at the knee are often coupled with decreased knee and hip flexion, and pronation at the subtalar joint.
Does your clinical experience support these findings? Do you know any other explanations for why lower – limb dominance might play a role in aetiology of ACL injuries?
All rights reserved to the British Journal of Sports Medicine.



1 comment: