Oslo Sports Trauma Research Center

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Information about project titled 'Determinants for knee valgus in a vertical drop jump'

Determinants for knee valgus in a vertical drop jump

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Project status: Published
Project manager: Agnethe Nilstad
Supervisor(s): Tron Krosshaug, Thor Einar Andersen
Coworker(s): Roald Bahr, Kam Ming Mok


Excessive knee valgus motion has been identified as being contributory to non-contact anterior cruciate ligament (ACL) injuries and is visually associated with a medial collapse of the knee during dynamic tasks. Furthermore, a link has been suggested between high knee valgus angles and abduction moments and ACL injury in female athletes.

Moreover, neuromuscular training programs focusing on improving frontal plane knee control and reducing knee valgus have been proven effective. Given the relationship between knee valgus loads and knee injuries, screening during dynamic tasks, such as the vertical drop jump, has been promoted to identify athletes at risk for knee injury. However, the underlying causes for an athlete to display greater knee valgus is not thoroughly investigated, although they may be important for targeting our injury prevention efforts.



The purpose of this study was to investigate the combined relationship between anatomical and neuromuscular characteristics and peak knee valgus angles in a vertical drop jump landing. We therefore aimed to assess whether greater measures of body height, femur and tibia length, anterior knee laxity and foot pronation, and lower quadriceps-, hamstrings- and hip abductor strength could predict greater peak knee valgus angles.



The current study is part of a larger cohort study aiming to investigate risk factors for ACL injuries in elite female football players (ACL risk factor study). We included elite female football players participating in baseline screening tests from 2009 through 2012.

The tests included marker-based 3D motion analysis of a vertical drop jump to assess peak knee valgus angles, and also tests assessing anatomical characteristics (height, static knee valgus, femur/tibia length, knee joint laxity and foot pronation) and lower extremity muscle strength (quadriceps, hamstrings and hip abductors).

A better understanding of the underlying factors that contribute to high knee valgus could help identifying athletes who may have an increased knee injury risk and thus would benefit from injury prevention training.