With his supervisor Tron Krosshaug, PhD student Kristianslund has looked at knee motion patterns in 120 elite female handball players who performed drop jumps and sidestep cutting. The study is now published in the American Journal of Sports Medicine.
Screening tests that identify athletes at increased risk of anterior cruciate ligament (ACL) injury may improve the compliance to preventive training.
Unfortunately, the current screening tests have not been found to reliably identify high-risk athletes.
A new OSTRC study highlights the challenges of drop jump screening tests in ACL injury research.
ACL injuries commonly occur in sidestep cutting, especially in handball. The handball sidestep cut involves a sudden change of direction, with high loading in one leg. This motion pattern is very different from the symmetrical and controlled drop jumps that are used for ACL injury screening (see athlete with poor landing mechanics below).
- If drop jump screening tests are to predict ACL injuries, we expect the same athletes to display high knee valgus angles and high knee abduction moments in drop jumps as in sidestep cutting, the study’s first author Eirik Klami Kristianslund explains.
Knee valgus and knee abduction moments are related to ACL injuries and this form the basis for the use of drop jump screening tests.
Poor correlation of knee loading between drop jumps and sidestep cutting
The present findings have implications for the interpretation of drop jump screening tests. The authors found significant differences between drop jumps and sidestep cutting in the ranking of athletes based on knee abduction moments.
This means: Athletes displaying the highest knee abduction moments in drop jumps were not necessarily among those with the highest knee abduction moments in sidestep cutting.
– Even if we can identify the athletes with inappropriate knee loading in drop jumps, we do not find the athletes with high-risk motion patterns in the situations where injuries occur, Kristianslund concludes.
Knee valgus angles were more consistent across tasks, but there was still only a moderate correlation.
All athletes should do preventive training, regardless of presumed injury risk!
This study shows that it is hard to predict an athlete´s sidestep cutting motion patterns based on his/her drop jump tests.
These findings can explain the lack of predictive value of previously published screening tests. The authors, Eirik Kristianslund and Tron Krosshaug, recommend all athletes to perform preventive training, regardless of their presumed injury risk!
Read the paper in the American Journal of Sports Medicine
ACL prevention program (in Norwegian)