Muscle activity patterns in female athletes susceptible to ACL injury.


Identification of Athletes at Future Risk of Anterior Cruciate Ligament Ruptures by Neuromuscular Screening.
Zebis M., Andersen L., Bencke J., Kjær M., Aagaard P. American Journal of Sports Medicine; 2009, 37, 1967 – 1973.

Literature provides evidence that ACL tears occur more frequently in females than males. Early osteoarthritis onset seems to be a major problem for those athletes following ACL injury whether they were treated surgically or conservatively. Thus, recent research work has been greatly focused on determining risk factors predisposing athletes to suffer ACL rupture. Studies suggest that most of the non – contact ACL tears are associated with situations like side – cutting, landing or rapid deceleration. Those mechanisms of injuries are linked with great eccentric knee extensors work and therefore high anterior – directed shear of the tibia. Apart from ACL, hamstrings also play crucial role in counteracting this movement. Authors performed neuromuscular screening to predict ACL injuries among 55 elite female team handball and soccer players. Athletes were screened for the pattern and magnitude of neuromuscular preactivity in relevant lower extremity muscles during side – cutting. ACL ruptures were registered in the following 2 match seasons.
5 players suffered ACL rupture to their preferred push – off lower limb during following 2 match seasons. Results indicated that subsequently injured female athletes had significantly lower preactivity of the semitendinous muscle and higher preactivity of the vastus lateralis muscles compared to uninjured players. Authors concluded that females with decreased activity of ST and increased activity of VL during side – cutting might be at higher risk of sustaining ACL tear. This study suggests the importance of ST muscle in compressing the medial knee joint and therefore limiting excessive knee valgus and external rotation of the knee joint and thus reducing the risk of ACL injury. Moreover, this study has a high clinical relevance highlighting the importance of preventive exercises focusing on strengthening medial hamstring and maintaining appropriate quadriceps to hamstrings ratio. Finally, authors believe that these findings might be relevant in respect to orthopaedic surgery, because ACL is commonly reconstructed using ST – GR graft. Despite there appears to be no evidence in the literature that hamstring autograft increases risk of reinjury, findings of this study suggest that ACL reconstructions with ST graft should be reconsidered. 
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